Document and Entity Information - USD ($) $ in Billions	12 Months Ended
Document and Entity Information - USD ($) $ in Billions	Dec. 31, 2017	Feb. 21, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	Nasdaq, Inc.
Entity Central Index Key	0001120193
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Trading Symbol	ndaq
Amendment Flag	false
Entity Common Stock, Shares Outstanding		166,560,632
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 8.3

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 377	$ 403
Restricted cash	22	15
Financial investments, at fair value	235	245
Receivables, net	423	429
Default funds and margin deposits	3,988	3,301
Other current assets	187	167
Assets held for sale	297	0
Total current assets	5,529	4,560
Property and equipment, net	400	362
Deferred tax assets	391	717
Goodwill	6,586	6,027
Intangible assets, net	2,468	2,094
Other non-current assets	412	390
Total assets	15,786	14,150
Current liabilities:
Accounts payable and accrued expenses	177	175
Section 31 fees payable to SEC	128	108
Accrued personnel costs	170	207
Deferred revenue	189	162
Other current liabilities	85	129
Default funds and margin deposits	3,988	3,301
Short-term debt	480	0
Liabilities held for sale	45	0
Total current liabilities	5,262	4,082
Long-term debt	3,727	3,603
Deferred tax liabilities	602	720
Non-current deferred revenue	146	171
Other non-current liabilities	162	144
Total liabilities	9,899	8,720
Commitments and contingencies
Nasdaq stockholders’ equity:
Common stock, $0.01 par value, 300,000,000 shares authorized, shares issued: 172,373,432 at December 31, 2017 and 170,501,186 at December 31, 2016; shares outstanding: 167,441,030 at December 31, 2017 and 166,579,468 at December 31, 2016	2	2
Additional paid-in capital	3,024	3,104
Common stock in treasury, at cost: 4,932,402 shares at December 31, 2017 and 3,921,718 shares at December 31, 2016	(247)	(176)
Accumulated other comprehensive loss	(862)	(979)
Retained earnings	3,970	3,479
Total Nasdaq stockholders’ equity	5,887	5,430
Total liabilities and equity	$ 15,786	$ 14,150

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	172,373,432	170,501,186
Common stock, shares outstanding (in shares)	167,441,030	166,579,468
Common stock in treasury (in shares)	4,932,402	3,921,718

Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
Consolidated Statements of Income - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues:
Market Services	$ 2,418	$ 2,255	$ 2,084
Corporate Services	656	635	562
Information Services	588	540	512
Market Technology	303	275	245
Total revenues	3,965	3,705	3,403
Transaction-based expenses:
Transaction rebates	(1,158)	(1,092)	(983)
Brokerage, clearance and exchange fees	(379)	(336)	(330)
Revenues less transaction-based expenses	2,428	2,277	2,090
Operating expenses:
Compensation and benefits	675	664	590
Professional and contract services	156	153	148
Computer operations and data communications	125	111	107
Occupancy	95	86	85
General, administrative and other	82	72	65
Marketing and advertising	31	30	28
Depreciation and amortization	188	170	138
Regulatory	33	35	27
Merger and strategic initiatives	44	76	10
Restructuring charges	0	41	172
Total operating expenses	1,429	1,438	1,370
Operating income	999	839	720
Interest income	7	5	4
Interest expense	(143)	(135)	(111)
Asset impairment charge	0	(578)	0
Other investment income	2	3	0
Net income from unconsolidated investees	15	2	17
Income before income taxes	880	136	630
Income tax provision	146	28	203
Net income	734	108	427
Net loss attributable to noncontrolling interests	0	0	1
Net income attributable to Nasdaq	$ 734	$ 108	$ 428
Per share information:
Basic earnings per share (in dollars per share)	$ 4.41	$ 0.65	$ 2.56
Diluted earnings per share (in dollars per share)	4.33	0.64	2.50
Cash dividends declared per common share (in dollars per share)	$ 1.46	$ 1.21	$ 0.9

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 734	$ 108	$ 427
Foreign currency translation gains (losses):
Net foreign currency translation gains (losses)	214	(183)	(283)
Income tax benefit (expense)	(96)	68	100
Total	118	(115)	(183)
Employee benefit plan gains (losses):
Employee benefit plan adjustment gains (losses)	(2)	0	2
Income tax benefit (expense)	1	0	(1)
Total	(1)	0	1
Total other comprehensive income (loss), net of tax	117	(115)	(182)
Comprehensive income (loss)	851	(7)	245
Comprehensive loss attributable to noncontrolling interests	0	0	1
Comprehensive income (loss) attributable to Nasdaq	$ 851	$ (7)	$ 246

Consolidated Statements of Changes in Equity - USD ($) $ in Millions	Total	Common stock	Additional Paid-in Capital	Common Stock In Treasury, at Cost	Accumulated Other Comprehensive Loss	Retained Earnings	Non- controlling Interests
Balance at Dec. 31, 2014	$ 5,794	$ 2	$ 3,222	$ (41)	$ (682)	$ 3,292	$ 1
Common stock, shares outstanding (in shares) at Dec. 31, 2014		168,795,263
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	427					428	(1)
Foreign currency translation, net of tax	(183)				(183)
Employee benefit plan adjustments, net of tax	1				1
Cash dividends declared per common share	(149)					(149)
Share repurchase program	(377)		(340)	(37)
Share repurchase program (in shares)		(7,191,685)
Share-based compensation	68		68
Share-based compensation (in shares)		1,455,380
Stock option exercises, net	$ 18		18
Stock options exercises, net (in shares)	682,054	682,054
Other issuances of common stock, net	$ 22		55	(33)
Other issuances of common stock, net (in shares)		(408,989)
Purchase of subsidiary shares to noncontrolling interests and other adjustments	(12)		(12)
Issuance of Nasdaq common stock related to a prior acquisition (in shares)		992,247
Common stock, shares outstanding (in shares) at Dec. 31, 2015		164,324,270
Balance at Dec. 31, 2015	5,609	$ 2	3,011	(111)	(864)	3,571	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	108					108
Foreign currency translation, net of tax	(115)				(115)
Employee benefit plan adjustments, net of tax	0
Cash dividends declared per common share	(200)					(200)
Share repurchase program	$ (100)		(100)
Share repurchase program (in shares)	(1,547,778)	(1,547,778)
Share-based compensation	$ 86		86
Share-based compensation (in shares)		2,361,699
Stock option exercises, net	$ 41		41
Stock options exercises, net (in shares)	1,219,820	1,219,820
Other issuances of common stock, net	$ 1		66	(65)
Other issuances of common stock, net (in shares)		(770,790)
Issuance of Nasdaq common stock related to a prior acquisition (in shares)		992,247
Common stock, shares outstanding (in shares) at Dec. 31, 2016		166,579,468
Balance at Dec. 31, 2016	5,430	$ 2	3,104	(176)	(979)	3,479	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	734					734
Foreign currency translation, net of tax	118				118
Employee benefit plan adjustments, net of tax	(1)				(1)
Cash dividends declared per common share	(243)					(243)
Share repurchase program	$ (203)		(203)
Share repurchase program (in shares)	(2,843,519)	(2,843,519)
Share-based compensation	$ 70		70
Share-based compensation (in shares)		2,384,821
Stock option exercises, net	$ 24		24
Stock options exercises, net (in shares)	1,102,830	1,102,830
Other issuances of common stock, net	$ (42)		29	(71)
Other issuances of common stock, net (in shares)		(774,817)
Issuance of Nasdaq common stock related to a prior acquisition (in shares)		992,247
Common stock, shares outstanding (in shares) at Dec. 31, 2017		167,441,030
Balance at Dec. 31, 2017	$ 5,887	$ 2	$ 3,024	$ (247)	$ (862)	$ 3,970	$ 0

Consolidated Statements of Changes in Equity (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Stockholders' Equity [Abstract]
Foreign currency translation, tax	$ 96	$ (68)	$ (100)
Employee benefit plan adjustments, tax	$ 1	$ 0	$ (1)

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Cash Flows [Abstract]
Net income	$ 734	$ 108	$ 427
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	188	170	138
Share-based compensation	70	86	68
Deferred income taxes	10	(136)	(14)
Non-cash restructuring charges	0	8	136
Asset impairment charge	0	578	0
Net income from unconsolidated investees	(15)	(2)	(17)
Other reconciling items included in net income	25	9	7
Net change in operating assets and liabilities, net of effects of acquisitions:
Receivables, net	25	(24)	55
Other assets	261	(18)	(41)
Accounts payable and accrued expenses	(12)	5	(38)
Section 31 fees payable to SEC	20	5	(26)
Accrued personnel costs	(41)	27	33
Deferred revenue	(43)	(15)	(49)
Other liabilities	(61)	(25)	48
Net assets held for sale	(252)	0	0
Net cash provided by operating activities	909	776	727
Cash flows from investing activities:
Purchases of trading securities	(366)	(443)	(346)
Proceeds from sales and redemptions of trading securities	394	392	319
Purchases of available-for-sale investment securities	(26)	(25)	(38)
Proceeds from maturities of available-for-sale investment securities	30	19	29
Capital contribution in equity method investment	0	0	(30)
Acquisition of businesses, net of cash and cash equivalents acquired	(776)	(1,460)	(226)
Purchases of property and equipment	(144)	(134)	(133)
Other investment activities	(2)	(6)	(10)
Net cash used in investing activities	(890)	(1,657)	(435)
Cash flows from financing activities:
Proceeds from commercial paper, net	480	0	0
Repayments of long-term debt	(708)	(1,156)	(369)
Payment of debt extinguishment cost	(9)	0	0
Proceeds from utilization of credit commitment, net of debt issuance costs	150	898	506
Proceeds from issuances of senior unsecured notes, net of debt issuance costs	498	1,159	0
Proceeds from issuance of term loan facility	0	399	0
Cash paid for repurchase of common stock	(203)	(100)	(377)
Cash dividends	(243)	(200)	(149)
Proceeds received from employee stock activity	53	54	29
Payments related to employee shares withheld for taxes	(71)	(65)	(34)
Proceeds (disbursements) of customer funds	0	(38)	13
Other financing activities	0	(3)	(19)
Net cash (used in) provided by financing activities	(53)	948	(400)
Effect of exchange rate changes on cash and cash equivalents and restricted cash	15	(6)	(11)
Net increase (decrease) in cash and cash equivalents and restricted cash	(19)	61	(119)
Cash and cash equivalents and restricted cash at beginning of period	418	357	476
Cash and cash equivalents and restricted cash at end of period	399	418	357
Cash paid for:
Interest	129	119	103
Income taxes, net of refund	$ 154	$ 191	$ 202

Organization and Nature of Operations	12 Months Ended
Organization and Nature of Operations	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Nature of Operations	Organization and Nature of Operations Nasdaq, Inc. is a leading provider of trading, clearing, marketplace technology, regulatory, securities listing, information and public and private company services. Our global offerings are diverse and include trading and clearing across multiple asset classes, trade management services, data products, financial indexes, capital formation solutions, corporate solutions, and market technology products and services. Our technology powers markets across the globe, supporting equity derivative trading, clearing and settlement, cash equity trading, fixed income trading, trading surveillance and many other functions. We manage, operate and provide our products and services in four business segments: Market Services, Corporate Services, Information Services and Market Technology. Market Services Our Market Services segment includes our Equity Derivative Trading and Clearing, Cash Equity Trading, FICC and Trade Management Services businesses. We operate multiple exchanges and other marketplace facilities across several asset classes, including derivatives, commodities, cash equity, debt, structured products and ETPs. In addition, in some countries where we operate exchanges, we also provide broker services, clearing, settlement and central depository services. Our transaction-based platforms provide market participants with the ability to access, process, display and integrate orders and quotes. The platforms allow the routing and execution of buy and sell orders as well as the reporting of transactions, providing fee-based revenues. In the U.S., we operate six electronic options exchanges and three cash equity exchanges. The Nasdaq Stock Market, the largest of our cash equities exchanges, is the largest single venue of liquidity for trading U.S.-listed cash equities. We also operate an electronic platform for trading of U.S. Treasuries and NFX, a U.S. based designated contract market which lists cash-settled energy derivatives based on key energy benchmarks including oil, natural gas and U.S. power. In addition, we also operate three Canadian markets for the trading of Canadian-listed securities. In Europe, we operate exchanges in Stockholm (Sweden), Copenhagen (Denmark), Helsinki (Finland), and Reykjavik (Iceland), as well as the clearing operations of Nasdaq Clearing. We also operate exchanges in Tallinn (Estonia), Riga (Latvia) and Vilnius (Lithuania) as Nasdaq Baltic. Collectively, Nasdaq Nordic and Nasdaq Baltic offer trading in cash equities, depository receipts, warrants, convertibles, rights, fund units and ETFs, as well as trading and clearing of derivatives and clearing of resale and repurchase agreements. Nasdaq Commodities is the brand name for Nasdaq’s worldwide suite of commodity-related products and services. Nasdaq Commodities’ offerings include oil, power, natural gas and carbon emission markets, tanker and dry cargo freight, seafood derivatives, iron ore, electricity certificates and clearing services. These products are listed on two of Nasdaq’s derivatives exchanges, Nasdaq Oslo ASA and NFX. Through our Trade Management Services business, we provide market participants with a wide variety of alternatives for connecting to and accessing our markets via a number of different protocols used for quoting, order entry, trade reporting, DROP functionality and connectivity to various data feeds. We also provide co-location services to market participants, whereby firms may lease cabinet space and power to house their own equipment and servers within our data centers. Our broker services operations offer technology and customized securities administration solutions to financial participants in the Nordic market. Corporate Services Our Corporate Services segment includes our Corporate Solutions and Listing Services businesses. Our Corporate Solutions business serves corporate clients, including companies listed on our exchanges and private companies. We help organizations manage the two-way flow of information with their key constituents, including their board members and investors, and with clients and the public through our suite of advanced technology, analytics, and consultative services. Our Corporate Solutions business currently offers products to serve the following key areas: investor relations, board & leadership, public relations solutions, and digital media services. As of September 30, 2017, our Public Relations Solutions and Digital Media Services businesses have been classified as held for sale. See Note 5, “Assets and Liabilities Held for Sale,” for further discussion. In January 2018, we announced that we entered into a definitive agreement to sell these businesses. See “Definitive Agreement to Sell our Public Relations Solutions and Digital Media Services Businesses,” of Note 21, “Subsequent Events,” for further discussion. Our Listing Services business includes our U.S. and European Listing Services businesses. We operate a variety of listing platforms around the world to provide multiple global capital raising solutions for private and public companies. Our main listing markets are The Nasdaq Stock Market and the Nasdaq Nordic and Nasdaq Baltic exchanges. Through Nasdaq First North, our Nordic and Baltic operations also offer alternative marketplaces for smaller companies and growth companies. Our Listing Services business also includes NPM, which provides liquidity solutions for private companies. As of December 31, 2017, there were 2,949 total listings on The Nasdaq Stock Market, including 373 ETPs. The combined market capitalization was approximately $11.6 trillion. In Europe, the Nasdaq Nordic and Nasdaq Baltic exchanges, together with Nasdaq First North, were home to 984 listed companies with a combined market capitalization of approximately $1.5 trillion. Information Services Our Information Services segment includes our Data Products and our Index Licensing and Services businesses. Our Data Products business sells and distributes historical and real-time quote and trade information to the sell-side, the buy-side, retail online brokers, proprietary trading shops, other venues, internet portals and data distributors. Our data products enhance transparency of market activity within our exchanges and provide critical information to professional and non-professional investors globally. Our Index Licensing and Services business develops and licenses Nasdaq branded indexes, associated derivatives, and financial products and also provides custom calculation services for third-party clients. As of December 31, 2017, we had 324 ETPs licensed to Nasdaq’s indexes which had $167 billion of assets under management. Market Technology Our Market Technology segment is a leading global technology solutions provider and partner to exchanges, clearing organizations, central securities depositories, regulators, banks, brokers and corporate businesses. Our Market Technology business is the sales channel for our complete global offering to other marketplaces. Market Technology provides technology solutions for trading, clearing, settlement, surveillance and information dissemination to markets with wide-ranging requirements, from the leading markets in the U.S., Europe and Asia to emerging markets in the Middle East, Latin America, and Africa. Our marketplace solutions can handle a wide array of assets, including cash equities, equity derivatives, currencies, various interest-bearing securities, commodities and energy products, and are currently powering more than 90 marketplaces in 50 countries. Market Technology also provides market surveillance services to broker-dealer firms worldwide, as well as enterprise governance, risk management and compliance software solutions.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

The consolidated financial statements are prepared in accordance with U.S. GAAP and include the accounts of Nasdaq, its wholly-owned subsidiaries and other entities in which Nasdaq has a controlling financial interest. When we do not have a controlling interest in an entity but exercise significant influence over the entity’s operating and financial policies, such investment is accounted for under the equity method of accounting. We recognize our share of earnings or losses of an equity method investee based on our ownership percentage. See “Equity Method Investments,” of Note 7, “Investments,” for further discussion of our equity method investments.

The accompanying consolidated financial statements reflect all adjustments which are, in the opinion of management, necessary for a fair statement of the results. These adjustments are of a normal recurring nature. All significant intercompany accounts and transactions have been eliminated in consolidation.

Certain prior year amounts have been reclassified to conform to the current year presentation.

Use of Estimates

The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts and the disclosure of contingent amounts in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates.

Foreign Currency

Foreign denominated assets and liabilities are remeasured into the functional currency at exchange rates in effect at the balance sheet date and recorded through the income statement. Gains or losses resulting from foreign currency transactions are remeasured using the rates on the dates on which those elements are recognized during the period, and are included in general, administrative and other expense in the Consolidated Statements of Income.

Translation gains or losses resulting from translating our subsidiaries’ financial statements from the local functional currency to the reporting currency, net of tax, are included in accumulated other comprehensive loss within stockholders’ equity in the Consolidated Balance Sheets. Assets and liabilities are translated at the balance sheet date while revenues and expenses are translated at the date the transaction occurs or at an applicable average rate.

Deferred taxes are not recorded on cumulative translation adjustments where we expect earnings of a foreign subsidiary to be indefinitely reinvested. The income tax effect of currency translation adjustments related to foreign subsidiaries that are not considered indefinitely reinvested is recorded as a component of deferred taxes with an offset to accumulated other comprehensive loss within stockholders’ equity in the Consolidated Balance Sheets.

Cash and Cash Equivalents

Cash and cash equivalents include all non-restricted cash in banks and highly liquid investments with original maturities of 90 days or less at the time of purchase. Such equivalent investments included in cash and cash equivalents in the Consolidated Balance Sheets were $183 million as of December 31, 2017 and $251 million as of December 31, 2016. Cash equivalents are carried at cost plus accrued interest, which approximates fair value due to the short maturities of these investments.

Restricted Cash

Current restricted cash, which was $22 million as of December 31, 2017 and $15 million as of December 31, 2016, is restricted from withdrawal due to a contractual or regulatory requirement or not available for general use and is classified as restricted cash in the Consolidated Balance Sheets. As of December 31, 2017 and 2016, current restricted cash primarily includes restricted cash held for our trading and clearing businesses.

Financial Investments

Financial investments, at fair value are primarily comprised of trading securities, mainly highly rated European government debt securities. Trading securities are bought principally to meet regulatory capital requirements for Nasdaq Clearing’s operations and are generally sold in the near term. Changes in fair value of trading securities are included in dividend and investment income. Financial investments that are classified as available-for-sale investment securities are carried at fair value with unrealized gains and losses, net of tax, reported in accumulated other comprehensive loss within stockholders’ equity in the Consolidated Balance Sheets. Realized gains and losses on these securities are included in earnings upon disposition of the securities using the specific identification method. In addition, realized losses are recognized when management determines that a decline in value is other than temporary, which requires judgment regarding the amount and timing of recovery. For financial investments that are classified as available-for-sale securities, we also consider the extent to which cost exceeds fair value, the duration of that difference, management’s judgment about the issuer’s current and prospective financial condition, as well as our intent and ability to hold the security until recovery of the unrealized losses.

Fair value of both trading and available-for-sale investment securities is generally obtained from third party pricing sources. When available, quoted market prices are used to determine fair value. If quoted market prices are not available, fair values are estimated using pricing models with observable market inputs. The inputs to the valuation models vary by the type of security being priced but are typically benchmark yields, reported trades, broker-dealer quotes, and prices of similar assets. Pricing models generally do not entail material subjectivity because the methodologies employed use inputs observed from active markets. See “Fair Value Measurements,” below for further discussion of fair value measures.

Receivables, net

Our receivables are concentrated with our member firms, market data distributors, listed companies, corporate solutions and market technology customers. Receivables are shown net of a reserve for uncollectible accounts. The reserve for bad debts is maintained at a level that management believes to be sufficient to absorb estimated losses in the accounts receivable portfolio. The reserve is increased by the provision for bad debts which is charged against operating results and decreased by the amount of charge-offs, net of recoveries. The provision for bad debts is included in general, administrative and other expense in the Consolidated Statements of Income. The amount charged against operating results is based on several factors including, but not limited to, a continuous assessment of the collectability of each account, the length of time a receivable is past due and our historical experience with the particular customer. In circumstances where a specific customer’s inability to meet its financial obligations is known (i.e., bankruptcy filings), we record a specific provision for bad debts against amounts due to reduce the receivable to the amount we reasonably believe will be collected. Due to changing economic, business and market conditions, we review the reserve for bad debts monthly and make changes to the reserve through the provision for bad debts as appropriate. If circumstances change (i.e., higher than expected defaults or an unexpected material adverse change in a major customer’s ability to pay), our estimates of recoverability could be reduced by a material amount. The total reserve netted against receivables in the Consolidated Balance Sheets was $9 million as of December 31, 2017, $13 million as of December 31, 2016 and $14 million as of December 31, 2015. The changes in the balance between periods was immaterial.

Default Funds and Margin Deposits

Nasdaq Clearing members’ cash contributions are included in default funds and margin deposits in the Consolidated Balance Sheets as both a current asset and a current liability. These balances may fluctuate over time due to changes in the amount of deposits required and whether members choose to provide cash or non-cash contributions. Non-cash contributions include highly rated government debt securities that must meet specific criteria approved by Nasdaq Clearing. Non-cash contributions are pledged assets that are not recorded in the Consolidated Balance Sheets as Nasdaq Clearing does not take legal ownership of these assets and the risks and rewards remain with the clearing members.

Derivative Financial Instruments and Hedging Activities

Non-Designated Derivatives

We use derivatives as economic hedges that are not designed as accounting hedges or do not qualify for hedge accounting treatment. For such derivative financial instruments, changes in fair value are reported in current period earnings.

We use foreign exchange forward contracts to manage foreign currency exposure of intercompany loans. These contracts are not designated as hedges for financial reporting purposes. The change in fair value of these contracts is recognized in general, administrative and other expense in the Consolidated Statements of Income and offsets the foreign currency impact recognized on the intercompany loans.

As of December 31, 2017 and 2016, the fair value amounts of our derivative instruments were immaterial.

Net Investment Hedges

Net assets of our foreign subsidiaries are exposed to volatility in foreign currency exchange rates. We may utilize net investment hedges to offset the translation adjustment arising from re-measuring our investment in foreign subsidiaries.

Our 2021 and 2023 Notes have been designated as a hedge of our net investment in certain foreign subsidiaries to mitigate the foreign exchange risk associated with certain investments in these subsidiaries. Any increase or decrease related to the remeasurement of the 2021 and 2023 Notes into U.S. dollars is recorded within accumulated other comprehensive loss in the Consolidated Balance Sheets. See “3.875% Senior Unsecured Notes,” and “1.75% Senior Unsecured Notes,” of Note 10, “Debt Obligations,” for further discussion.

Property and Equipment, net

Property and equipment, including leasehold improvements, are carried at cost less accumulated depreciation and amortization. Depreciation and amortization are recognized using the straight-line method over the estimated useful lives of the related assets, which range from 10 to 40 years for buildings and improvements, 2 to 5 years for data processing equipment, and 5 to 10 years for furniture and equipment.

We develop systems solutions for both internal and external use. Certain costs incurred in connection with developing or obtaining internal use software are capitalized. In addition, certain costs of computer software to be sold, leased, or otherwise marketed as a separate product or as part of a product or process are capitalized beginning when a product’s technological feasibility has been established and ending when a product is available for general release. Technological feasibility is established upon completion of a detailed program design or, in its absence, completion. Prior to reaching technological feasibility, all costs are charged to expense. Unamortized capitalized costs are included in data processing equipment and software, within property and equipment, net in the Consolidated Balance Sheets. Capitalized software costs are amortized on a straight-line basis over the estimated useful lives of the software, generally 3 to 5 years. Amortization of these costs is included in depreciation and amortization expense in the Consolidated Statements of Income.

Leasehold improvements are amortized using the straight-line method over the shorter of their estimated useful lives or the remaining term of the related lease.

See Note 8, “Property and Equipment, net,” for further discussion.

Goodwill and Indefinite-Lived Intangible Assets

Goodwill represents the excess of purchase price over the value assigned to the net assets, including identifiable intangible assets, of a business acquired. Goodwill is assessed for impairment annually in the fourth quarter of our fiscal year using an October 1 measurement date, or more frequently if conditions exist that indicate that the asset may be impaired, such as changes in the business climate, poor indicators of operating performance or the sale or disposition of a significant portion of a reporting unit. When testing goodwill for impairment, we have the option of first performing a qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount as the basis to determine if it is necessary to perform a quantitative goodwill impairment test. In performing a qualitative assessment, we consider the extent to which unfavorable events or circumstances identified, such as changes in economic conditions, industry and market conditions or company specific events, could affect the comparison of the reporting unit’s fair value with its carrying amount. If we choose not to complete a qualitative assessment for a given reporting unit, or if the initial assessment indicates that it is more likely than not that the carrying amount of a reporting unit exceeds its estimated fair value, a quantitative test is required.

When assessing goodwill for impairment, our decision to perform a qualitative impairment assessment for a reporting unit in a given year is influenced by a number of factors, including but not limited to, the size of the reporting unit’s goodwill, the significance of the excess of the reporting unit’s estimated fair value over its carrying amount at the last quantitative assessment date, and the amount of time in between quantitative fair value assessments.

The quantitative goodwill test consists of two steps:


•	The first step compares the fair value of each reporting unit with its carrying amount, including goodwill. If the reporting unit’s fair value exceeds its carrying amount, goodwill is not impaired.


•	If the fair value of a reporting unit is less than its carrying amount, the second step of the goodwill test is performed to measure the amount of impairment, if any. An impairment is equal to the excess of the carrying amount of goodwill over its fair value.

We also evaluate indefinite-lived intangible assets for impairment annually in the fourth quarter of our fiscal year using an October 1 measurement date, or more frequently whenever events or changes in circumstances indicate that the fair value of the asset may be less than its carrying amount. Such evaluation includes determining the fair value of the asset and comparing the fair value of the asset with its carrying amount. If the fair value of the indefinite-lived intangible asset is less than its carrying amount, an impairment charge is recognized in an amount equal to the difference.

For indefinite-lived intangible assets impairment testing, we also have the option to first perform a qualitative assessment to determine whether it is more likely than not that the fair value of an indefinite-lived intangible asset is less than the carrying amount. If, after assessing the totality of events or circumstances, we determine that it is more likely than not that the fair value of an indefinite-lived intangible asset is less than its carrying amount, then we must perform additional testing of the asset. Otherwise, we conclude that no impairment is indicated and further testing is not performed.

There was no impairment of goodwill for the years ended December 31, 2017, 2016 and 2015 and there were no indefinite-lived intangible asset impairment charges in 2017. As discussed in “Intangible Asset Impairment Charges,” of Note 6, “Goodwill and Acquired Intangible Assets,” we recorded pre-tax, non-cash indefinite-lived intangible asset impairment charges of $578 million in 2016 and $119 million in 2015. There was no other impairment of indefinite-lived intangible assets for the years ended December 31, 2016 and 2015. Disruptions to our business and events, such as economic weakness or unexpected significant declines in the operating results of any of our reporting units or businesses, may result in goodwill or indefinite-lived intangible asset impairment charges in the future.

Valuation of Other Long-Lived Assets

We review our other long-lived assets, such as finite-lived intangible assets and property and equipment, for potential impairment when there is evidence that events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The carrying amount of an asset is not recoverable if it exceeds the sum of the undiscounted cash flows expected to result from the use and eventual disposition of the asset. Any required impairment loss is measured as the amount by which the carrying amount of the asset exceeds its fair value and is recorded as a reduction in the carrying amount of the related asset and a charge to operating results. See Note 8, “Property and Equipment, net,” for further discussion of property and equipment asset impairment charges recorded in 2017, 2016 and 2015.

Equity Method Investments

In general, the equity method of accounting is used when we own 20% to 50% of the outstanding voting stock of a company and when we are able to exercise significant influence over the operating and financial policies of a company. We have certain investments in which we have determined that we have significant influence and as such account for the investments under the equity method of accounting. We record our pro-rata share of earnings or losses each period and record any dividends as a reduction in the investment balance. We evaluate our equity method investments for other-than-temporary declines in value by considering a variety of factors such as the earnings capacity of the investment and the fair value of the investment compared to its carrying amount. In addition, for investments where the market value is readily determinable, we consider the underlying stock price. If the estimated fair value of the investment is less than the carrying amount and management considers the decline in value to be other than temporary, the excess of the carrying amount over the estimated fair value is recognized in the financial statements as an impairment. See “Equity Method Investments,” of Note 7, “Investments,” for further discussion of an other-than-temporary charge recorded in 2016 on an equity method investment.

Cost Method Investments

In general, the cost method of accounting is used when we own less than 20% of the outstanding voting stock of a company which does not have a readily determinable fair value and when we are not able to exercise significant influence over the operating and financial policies of a company. Under the cost method of accounting, investments are carried at cost and are adjusted only for other-than-temporary declines in fair value, certain distributions, and additional investments. We evaluate our cost method investments for other-than-temporary declines in value by considering a variety of factors such as the earnings capacity of the investment.

Revenue Recognition and Transaction-Based Expenses

Market Services Revenues

Market services revenues include equity derivative trading and clearing revenues, cash equity trading revenues, FICC revenues, and trade management services revenues.

Equity Derivative Trading and Clearing and Cash Equity Trading Revenues

Equity Derivative Trading and Clearing Revenues

In our equity derivative markets, we earn trading and clearing revenues which are variable. In the U.S., trading revenues are based on traded volumes, and recognized when executed. The principal types of equity derivative contracts traded are equity options, ETF options, index options and foreign currency options. In the U.S., we record execution revenues from transactions on a gross basis as revenues and record related expenses as transaction-based expenses, as we have certain risk associated with trade execution. See “Equity Derivative Trading and Clearing and Cash Equity Trading Transaction-Based Expenses” below for further discussion.

In Europe, equity derivative trading and clearing revenues are based on the volume and value of traded and cleared contracts, and recognized when executed or when contracts are cleared. The principal types of equity derivative contracts traded and cleared are stock options and futures and index options and futures.

Cash Equity Trading Revenues

U.S. cash equity trading revenues are variable, based on individual customer share volumes, and recognized as transactions occur. We charge transaction fees for executing cash equity trades in Nasdaq-listed and other listed securities on our U.S. cash equity exchanges, as well as on orders that are routed to and executed on other market venues for execution. Similar to U.S. equity derivative trading and clearing, we record cash equity trading revenues from transactions on a gross basis as revenues and record related expenses as transaction-based expenses, as we have certain risk associated with trade execution. For further discussion see “Equity Derivative Trading and Clearing and Cash Equity Trading Transaction-Based Expenses” below.

In our European cash equity markets, we charge transaction fees for executing trades on the exchanges that comprise Nasdaq Nordic and Nasdaq Baltic. These transaction fees are charged per executed order and as per value traded.

Equity Derivative Trading and Clearing and Cash Equity Trading Transaction-Based Expenses

For U.S. equity derivative trading, we credit a portion of the per share execution charge to the market participant that provides the liquidity. For U.S. cash equity trading, for Nasdaq and Nasdaq PSX, we credit a portion of the per share execution charge to the market participant that provides the liquidity and for Nasdaq BX, we credit a portion of the per share execution charge to the market participant that takes the liquidity. We record these credits as transaction rebates that are included in transaction-based expense in the Consolidated Statements of Income. These transaction rebates are paid on a monthly basis and the amounts due are included in accounts payable and accrued expenses in the Consolidated Balance Sheets.

In the U.S., we pay Section 31 fees to the SEC for supervision and regulation of securities markets. We pass these costs along to our customers through our equity derivative trading and clearing fees and our cash equity trading fees. We collect the fees as a pass-through charge from organizations executing eligible trades on our options exchanges and our cash equity platforms and we recognize these amounts in transaction-based expenses when incurred. Section 31 fees received are included in cash and cash equivalents in the Consolidated Balance Sheets at the time of receipt and, as required by law, the amount due to the SEC is remitted semiannually and recorded as Section 31 fees payable to the SEC in the Consolidated Balance Sheets until paid. Since the amount recorded as revenues is equal to the amount recorded as transaction-based expenses, there is no impact on our revenues less transaction-based expenses. As we hold the cash received until payment to the SEC, we earn interest income on the related cash balances.

Under our Limitation of Liability Rule and procedures, we may, subject to certain caps, provide compensation for losses directly resulting from the systems’ actual failure to correctly process an order, quote, message or other data into our platform. We do not record a liability for any potential claims that may be submitted under the Limitation of Liability Rule unless they meet the provisions required in accordance with U.S. GAAP. As such, losses arising as a result of the rule are accrued and charged to expense only if the loss is probable and estimable.

The exchanges that comprise Nasdaq Nordic and Nasdaq Baltic do not have any revenue sharing agreements or transaction-based expenses, such as transaction rebates and brokerage, clearance and exchange fees.

FICC Revenues

Fixed income trading revenues are primarily earned from trading of U.S. Treasury securities and other fixed income products. Customer contracts may be on a fixed or variable rate basis. Revenues from customer contracts with a fixed rate basis are recognized ratably over the contract period. Revenues from customer contracts with a variable rate basis are based upon individual customer share volume and are recognized as revenues as the transaction occurs. Commodities trading and clearing revenues are primarily earned from trading and clearing of energy, emission allowance, freight, seafood and other commodity products. Trading and clearing revenues are based on the volume and value of traded and cleared contracts, and recognized when executed or when contracts are cleared. In addition, Nasdaq Commodities members are billed an annual fee which is recognized ratably over the following 12-month period.

We also generate clearing revenues for OTC traded derivatives, interest rate swaps, and resale and repurchase agreements. These clearing revenues are based on the value and length of the contract and are recognized when cleared. In connection with our collateral management process in our Nasdaq Clearing operations, we recognize interest income on cash contributions that we manage when earned.

Trade Management Services Revenues

Access Services

We generate revenues by providing market participants with several alternatives for connecting to and accessing our markets for a fee. The type of connectivity is determined by the level of functionality a customer needs. As a result, access services revenues vary depending on the type of connection provided to customers. We provide co-location services to market participants, whereby firms may lease cabinet space and power to house their own equipment and servers within our data centers. These participants are charged monthly fees for cabinet space, connectivity and support. Additionally, we offer a number of wireless connectivity routes between select data centers using millimeter wave and microwave technology. We also earn revenues from annual and monthly exchange membership and registration fees. Revenues for providing access to our markets, co-location services and monthly exchange membership and registration fees are recognized on a monthly basis as the service is provided. Revenues from annual fees for exchange membership and registration fees are recognized ratably over the following 12-month period.

Broker Services

Our broker services operations offer technology and customized securities administration solutions to financial participants in the Nordic market. The primary services offered are flexible back-office systems, which allow customers to entirely or partly outsource their company’s back-office functions. Revenues from broker services are based on a fixed basic fee for administration or licensing, maintenance and operations, and a variable portion that depends on the number of transactions completed. Broker services revenues are recognized on a continuous basis as services are rendered.

Corporate Services Revenues

Corporate services revenues include corporate solutions revenues and listing services revenues.

Corporate Solutions Revenues

Corporate solutions revenues primarily include subscription and transaction-based income from our investor relations, board & leadership, public relations solutions, and digital media services products. Subscription-based revenues earned are recognized ratably over the contract period, generally one to two years in length. As part of the subscription agreements, customers can also be charged usage fees based upon actual usage of the services provided. Revenues from usage fees and other services are recognized when earned. Revenues from transaction-based services, such as webcasting and wire distribution, are recorded as the services are provided and delivered.

Listing Services Revenues

Listing services revenues primarily include annual renewal fees, initial listing fees and listing of additional shares fees.

Annual Renewal Fees

In the U.S., annual renewal fees are charged based on the number of outstanding shares of companies listed in the U.S. at the end of the prior year and are recognized ratably over the following 12-month period. European annual renewal fees, which are received from companies listed on our Nasdaq Nordic and Nasdaq Baltic exchanges and Nasdaq First North, are directly related to the listed companies’ market capitalization on a trailing 12-month basis.

Initial Listing Fees

Initial listing fees are generally based on the number of shares that a company initially lists and are recognized on a straight-line basis over estimated service periods of six years, based on our historical listing experience and projected future listing duration.

Listing of Additional Shares Fees

Listing of additional shares fees are paid by listed companies in connection with corporate actions involving the issuance of new shares to be listed, such as stock splits and sales of additional securities. These fees are recognized on a straight-line basis over estimated service periods of four years, based on our historical listing experience and projected future listing duration.

Listing of additional share fees have been phased out effective January 2018 as a result of our all-inclusive annual listing fee program for our U.S. markets. See “All-Inclusive Annual Listing Fee Program” below for further discussion.

All-Inclusive Annual Listing Fee Program

Nasdaq announced an all-inclusive annual listing fee program for companies listed in the U.S. which became effective in 2015. Under this program, listed companies pay an annual fee which includes all listing-related activities, including listing of additional shares. All listed companies are subject to the all-inclusive program effective January 2018. These revenues are recognized ratably over the following 12-month period.

Revenue recognition for our Listing Services business was impacted due to the adoption of ASU 2014-09, “Revenue from Contracts with Customers.” See “Recent Accounting Pronouncements,” of Note 2, “Summary of Significant Accounting Policies,” for further discussion.

Information Services Revenues

Information services revenues include data products revenues and index licensing and services revenues.

Data Products Revenues

Data products revenues are earned from U.S. and European proprietary data products and index data products. In the U.S., we also earn revenues from U.S. tape plans.

We collect, process and create information from our exchanges and earn revenues as a distributor of our own data, as well as select, third-party content. We provide varying levels of quote and trade information to our customers, who in turn sell subscriptions for this information. In 2017, we expanded our offering through the acquisition of eVestment, a leading data and analytics provider to the asset management industry. We earn revenues primarily based on the number of data subscribers and distributors of our data. Data products revenues are subscription-based and are recognized on a monthly basis net of amounts due under revenue sharing arrangements with market participants.

We also generate revenues from our Nasdaq indexes that consist of Global Index Data Services, which delivers real-time index values throughout the trading day, and Global Index Watch/Global Index File Delivery Service, which delivers weightings and components data, corporate actions and a breadth of additional data. We earn revenues primarily based on the number of data subscribers and distributors of our data. These revenues, which are subscription based, are recognized on a monthly basis.

Revenues from U.S. tape plans include eligible UTP Plan revenues that are shared among UTP Plan participants and are presented on a net basis. The Nasdaq Stock Market acts as the processor and administrator for the UTP Plan. The UTP Plan administrator sells quotation and last sale information for all transactions in Nasdaq-listed securities, whether traded on The Nasdaq Stock Market or other exchanges, to market participants and to data distributors, who then provide the information to subscribers. After deducting costs, as permitted under the revenue sharing provision of the UTP Plan, the UTP Plan administrator distributes the tape revenues to the respective UTP Plan participants, including The Nasdaq Stock Market, Nasdaq BX and Nasdaq PSX, based on a formula required by Regulation NMS that takes into account both trading and quoting activity. In addition, much like Nasdaq-listed securities, all quotes and trades in NYSE- and NYSE American-listed securities are reported and disseminated in real-time, and as such, we share in the tape revenues for information on NYSE- and NYSE American-listed securities. Revenues from net U.S. tape plans are recognized on a monthly basis.

Data Products Revenue Sharing

The most significant component of data products revenues recorded on a net basis is the UTP Plan revenue sharing in the U.S. All indicators of gross versus net reporting under U.S. GAAP have been considered in analyzing the appropriate presentation of UTP Plan revenue sharing. However, the following are the primary indicators of net reporting:


•	Primary Obligor: We are the administrator for the UTP Plan, in addition to being a participant in the UTP Plan. In our unique role as administrator, we facilitate the collection and dissemination of revenues on behalf of the UTP Plan participants. As a participant, we share in the net distribution of revenues according to the plan on the same terms as all other plan participants.


•	Risk of Loss/Credit Risk: Risk of loss on the revenue is shared equally among plan participants according to the UTP Plan.


•	Price Latitude: The operating committee of the UTP Plan, which is comprised of representatives from each of the participants, including us solely in our capacity as a UTP Plan participant, is responsible for setting the level of fees to be paid by distributors and subscribers and taking action in accordance with the provisions of the UTP Plan, subject to SEC approval.

The exchanges that comprise Nasdaq Nordic and Nasdaq Baltic do not have any data products revenue sharing agreements.

Index Licensing and Services Revenues

We develop and license Nasdaq branded indexes, associated derivatives and financial products as part of our Global Index Family. We also provide custom calculation services for third-party clients. Revenues primarily include license fees from these branded indexes, associated derivatives and financial products in the U.S. and abroad. We primarily have two types of license agreements: transaction-based licenses and asset-based licenses. Transaction-based licenses are generally renewable long-term agreements. Customers are charged based on transaction volume or a minimum contract amount, or both. If a customer is charged based on transaction volume, we recognize revenue when the transaction occurs. If a customer is charged based on a minimum contract amount, we recognize revenue on a pro-rata basis over the licensing term. Asset-based licenses are also generally long-term agreements. Customers are charged based on a percentage of assets under management for licensed products, per the agreement, on a monthly or quarterly basis. These revenues are recognized over the term of the license agreement.

Market Technology Revenues

Market Technology provides technology solutions for trading, clearing, settlement, surveillance and information dissemination, as well as enterprise governance, risk management and compliance software solutions. Revenues primarily consist of software, license and support revenues, change request and advisory revenues, and software as a service revenues.

For most solutions, we enter into multiple-element sales arrangements to develop technology solutions, license the right to use software, and provide post-contract support and other services to our customers. In order to recognize revenues associated with each individual element of a multiple-element sales arrangement separately, we are required to establish the existence of VSOE of fair value for each element. When VSOE for individual elements of an arrangement cannot be established, revenue is generally deferred and recognized over either the final element of the arrangement or the entire term of the arrangement for which the services will be delivered.

We enter into agreements to modify the system solutions sold by Nasdaq after delivery has occurred. These revenues are recognized when earned.

In addition, we enter into revolving subscription agreements which allow customers to connect to our servers to access certain services. These revenues are recognized ratably over the subscription term.

Revenue recognition for our Market Technology business was impacted due to the adoption of ASU 2014-09, “Revenue from Contracts with Customers.” See “Recent Accounting Pronouncements,” of Note 2, “Summary of Significant Accounting Policies,” for further discussion.

Earnings Per Share

We present both basic and diluted earnings per share. Basic earnings per share is computed by dividing net income attributable to Nasdaq by the weighted-average number of common shares outstanding for the period. Diluted earnings per share is computed by dividing net income attributable to Nasdaq by the weighted-average number of common shares and common share equivalents outstanding during the period and reflects the assumed conversion of all dilutive securities, which primarily consist of employee stock options, restricted stock, and PSUs. Common share equivalents are excluded from the computation in periods for which they have an anti-dilutive effect. Stock options for which the exercise price exceeds the average market price over the period are anti-dilutive and, accordingly, are excluded from the calculation. See Note 15, “Earnings Per Share,” for further discussion.

Pension and Post-Retirement Benefits

Pension and other post-retirement benefit plan information for financial reporting purposes is developed using actuarial valuations. We assess our pension and other post-retirement benefit plan assumptions on a regular basis. In evaluating these assumptions, we consider many factors, including evaluation of the discount rate, expected rate of return on plan assets, mortality rate, healthcare cost trend rate, retirement age assumption, our historical assumptions compared with actual results and analysis of current market conditions and asset allocations. See Note 12, “Retirement Plans,” for further discussion.

Discount rates used for pension and other post-retirement benefit plan calculations are evaluated annually and modified to reflect the prevailing market rates at the measurement date of a high-quality fixed-income debt instrument portfolio that would provide the future cash flows needed to pay the benefits included in the benefit obligations as they come due. Actuarial assumptions are based upon management’s best estimates and judgment.

The expected rate of return on plan assets for our U.S. pension plans represents our long-term assessment of return expectations which may change based on significant shifts in economic and financial market conditions. The long-term rate of return on plan assets is derived from return assumptions based on targeted allocations for various asset classes. While we consider the pension plans’ recent performance and other economic growth and inflation factors, which are supported by long-term historical data, the return expectations for the targeted asset categories represent a long-term prospective return.

Share-Based Compensation

Nasdaq uses the fair value method of accounting for share-based awards. Share-based awards, or equity awards, include stock options, restricted stock, and PSUs. The fair value of stock options are estimated using the Black-Scholes option-pricing model. The fair value of restricted stock awards and PSUs, other than PSUs granted with market conditions, is determined based on the grant date closing stock price less the present value of future cash dividends. We estimate the fair value of PSUs granted with market conditions using a Monte Carlo simulation model at the date of grant.

We generally recognize compensation expense for equity awards on a straight-line basis over the requisite service period of the award, taking into account an estimated forfeiture rate.

Excess tax benefits or expense related to employee share-based payments, if any, are recognized as income tax benefit or expense in the Consolidated Statements of Income when the awards vest or are settled.

Nasdaq also has an ESPP that allows eligible employees to purchase a limited number of shares of our common stock at six-month intervals, called offering periods, at 85.0% of the lower of the fair market value on the first or the last day of each offering period. The 15.0% discount given to our employees is included in compensation and benefits expense in the Consolidated Statements of Income.

See Note 13, “Share-Based Compensation,” for further discussion of our share-based compensation plans.

Leases

We expense rent from non-cancellable operating leases, net of sublease income, on a straight line basis, based on future minimum lease payments. The net costs are included in occupancy expense in the Consolidated Statements of Income. See Note 18, “Leases,” for further discussion.

Fair Value Measurements

Fair value is defined as the price that would be received from selling an asset or paid to transfer a liability, or the exit price, in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be either recorded or disclosed at fair value, we consider the principal or most advantageous market in which we would transact, and we also consider assumptions that market participants would use when pricing the asset or liability. Fair value measurement establishes a hierarchy of valuation techniques based on whether the inputs to those valuation techniques are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect Nasdaq’s market assumptions. These two types of inputs create the following fair value hierarchy:


•	Level 1—Quoted prices for identical instruments in active markets.


•	Level 2—Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable.


•	Level 3—Instruments whose significant value drivers are unobservable.

This hierarchy requires the use of observable market data when available.

See Note 16, “Fair Value of Financial Instruments,” for further discussion.

Tax Matters

We use the asset and liability method to determine income taxes on all transactions recorded in the consolidated financial statements. Deferred tax assets and liabilities are determined based on differences between the financial statement carrying amounts and the tax basis of existing assets and liabilities (i.e., temporary differences) and are measured at the enacted rates that will be in effect when these differences are realized. If necessary, a valuation allowance is established to reduce deferred tax assets to the amount that is more likely than not to be realized.

In order to recognize and measure our unrecognized tax benefits, management determines whether a tax position is more likely than not to be sustained upon examination, including resolution of any related appeals or litigation processes, based on the technical merits of the position. Once it is determined that a position meets the recognition thresholds, the position is measured to determine the amount of benefit to be recognized in the consolidated financial statements. Interest and/or penalties related to income tax matters are recognized in income tax expense.

The Tax Cuts and Jobs Act was enacted on December 22, 2017. We are required to recognize the effect of the tax law changes in the period of enactment, such as remeasuring our U.S. deferred tax assets and liabilities, reassessing the net realizability of deferred tax assets and liabilities, and determining the applicability of the one-time mandatory transition tax on accumulated foreign earnings. SAB 118 has provided guidance which allows us to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. As of December 31, 2017, we have recorded a provisional estimate of the effects of the new legislation. We will continue to analyze the Tax Cuts and Jobs Act and related accounting guidance and interpretations in order to finalize any impacts within the measurement period.

See Note 11, “Income Taxes,” for further discussion.

Recent Accounting Pronouncements



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Compensation - Stock Compensation In March 2016, the FASB issued ASU 2016-09, “Improvements to Employee Share-Based Payment Accounting.”	This ASU involves several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This guidance requires all income tax effects of awards to be recognized as income tax expense or benefit in the income statement when the awards vest or are settled, as opposed to additional paid-in-capital where it was previously recorded. This guidance impacts the calculation of our total diluted share count for the earnings per share calculation, as calculated under the treasury stock method. It also allows an employer to repurchase more of an employee’s shares for tax withholding purposes without triggering liability accounting. All tax-related cash flows resulting from share-based payments are reported as operating activities on the statement of cash flows. In regards to forfeitures, a policy election is required to either estimate the number of awards that are expected to vest or account for forfeitures as they occur.	We adopted this standard on January 1, 2017 on a prospective basis for the impacts on the accounting for income taxes and the effect on earnings per share. We adopted the changes for the cash flow statement classification retrospectively.	The adoption resulted in the recognition of excess tax benefits in our provision for income taxes rather than additional paid-in capital of $40 million for the year ended December 31, 2017.
Compensation - Stock Compensation In May 2017, the FASB issued ASU 2017-09, “Scope of Modification Accounting.”	This ASU clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) change as a result of the change in terms or conditions.	We adopted this standard on June 30, 2017 on a prospective basis.	Adopting this standard had no impact on our consolidated financial statements. The future impact will depend on the extent and nature of future changes to the terms of our share-based payment awards. Historically, we have not had significant changes to our share-based payment awards and therefore do not expect adoption of this guidance to have a material impact on our consolidated financial statements.
Business Combination In January 2017, the FASB issued ASU 2017-01, “Clarifying the Definition of a Business.”	This ASU clarifies the definition of a business with the objective of adding guidance to assist companies with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The new guidance is expected to reduce the number of transactions that need to be further evaluated as businesses. Early adoption is permitted for certain types of transactions.	We adopted this standard on January 1, 2018 on a prospective basis.	None. However, this standard may impact how we account for future acquisitions.



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Goodwill In January 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment.”	This ASU simplifies how an entity is required to test goodwill for impairment and removes the second step of the goodwill impairment test, which required a hypothetical purchase price allocation if the fair value of a reporting unit is less than its carrying amount. Goodwill impairment will now be measured using the difference between the carrying amount and the fair value of the reporting unit and the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The amendments in this ASU should be applied on a prospective basis. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017.	January 1, 2020, with early adoption as of January 1, 2017 permitted.	We do not anticipate a material impact on our consolidated financial statements at the time of adoption of this new standard as the carrying amounts of our reporting units have been less than their corresponding fair values in recent years. Therefore, the second step of the goodwill impairment test was not required. However, changes in future projections, market conditions and other factors may cause a change in the excess of fair value of our reporting units over their corresponding carrying amounts. We do not anticipate early adoption of this standard.
Financial Instruments - Credit Losses In June 2016, the FASB issued ASU 2016-13, “Measurement of Credit Losses on Financial Instruments.”	This ASU changes the impairment model for certain financial instruments. The new model is a forward looking expected loss model and will apply to financial assets subject to credit losses and measured at amortized cost and certain off-balance sheet credit exposures. This includes loans, held-to-maturity debt securities, loan commitments, financial guarantees and net investments in leases, as well as trade receivables. For available-for-sale debt securities with unrealized losses, credit losses will be measured in a manner similar to today, except that the losses will be recognized as allowances rather than reductions in the amortized cost of the securities.	January 1, 2020, with early adoption permitted as of January 1, 2019.	We are currently assessing the impact that this standard will have on our consolidated financial statements. We do not anticipate early adoption of this standard.



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Leases In February 2016, the FASB issued ASU 2016-02, “Leases.”	Under this ASU, at the commencement date, lessees will be required to recognize a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. This guidance is not applicable for leases with a term of 12 months or less. Lessor accounting is largely unchanged.	January 1, 2019, with early adoption permitted.	When adopted, ASU 2016-02 will result in an increase in the assets and liabilities reflected on our consolidated balance sheets. In addition, we will be required to disclose key information about our leases. We are currently assessing the significance that this standard will have on our consolidated financial statements. We do not anticipate early adoption of this standard.
Financial Instruments - Overall In January 2016, the FASB issued ASU 2016-01, “Recognition and Measurement of Financial Assets and Financial Liabilities.”	This ASU requires that most equity investments be measured at fair value, with subsequent changes in fair value recognized in net income. Under this new guidance, Nasdaq will no longer be able to recognize unrealized holding gains and losses on equity securities classified today as available-for-sale in accumulated other comprehensive income within stockholders’ equity. For certain equity investments that do not have readily determinable fair values, there is a new measurement alternative where those investments are measured at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. This new standard does not change the guidance for classifying and measuring investments in debt securities and loans. This new guidance also impacts financial liabilities accounted for under the fair value option and affects the presentation and disclosure requirements for financial assets and liabilities.	We adopted this standard on January 1, 2018 on a prospective basis.	Since we do not have a significant investment in financial instruments impacted by this standard at the time of adoption, there was no material impact on our consolidated financial statements. We have elected the measurement alternative for equity investments which were historically accounted for under the cost method of accounting. This could result in volatility in earnings.



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Income Statement - Reporting Comprehensive Income In February 2018, the FASB issued ASU 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.”	This ASU provides an election to reclassify tax effects that are stranded in accumulated other comprehensive income as a result of tax reform to retained earnings. An election is also available to reclassify other stranded tax effects that relate to the Tax Cuts and Jobs Act but do not directly relate to the change in the federal rate. Tax effects that are stranded in accumulated other comprehensive income for other reasons (e.g., prior changes in tax law, a change in valuation allowance) may not be reclassified. Previously, the effects of changes in tax rates and laws on deferred tax balances were required to be recorded as a component of tax expense related to continuing operations for the period in which the law was enacted, even if the assets and liabilities related to items of accumulated other comprehensive income. In other words, backward tracing of the income tax effects of items originally recognized through accumulated other comprehensive income was prohibited.	January 1, 2019, with early adoption permitted.	We are currently assessing the impact that this standard will have on our consolidated financial statements.
Revenue From Contracts With Customers In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes the revenue recognition guidance in Accounting Standards Codification, “Revenue Recognition.”	The new revenue recognition standard sets forth a five-step revenue recognition model to determine when and how revenue is recognized. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration it expects to receive in exchange for those goods or services. The standard also requires more detailed disclosures. The standard provides alternative methods of initial adoption.	We adopted this standard on January 1, 2018 using the full retrospective method.	See discussion below.

Revenue From Contracts With Customers

Revenue and expense recognition for our Market Technology business and revenue recognition for our Listing Services business were impacted due to the adoption of Topic 606; however, the impact on our consolidated financial statements at the time of adoption was not material. There was no impact to revenue and expense recognition for our other businesses.

Market Technology. In our Market Technology business, we enter into contracts with customers to develop technology solutions, license the right to use software, and provide post-contract support and other services to our customers. Under accounting

policies prior to the adoption of Topic 606, we did not recognize revenue or expense until we began the final stage of the contract as we are not able to establish VSOE for individual elements of the contract. Under Topic 606, we no longer defer recognition of revenue and expense until the final stage of the contract. For each of our contracts, we have identified multiple performance obligations, allocated the transaction price to these obligations and are recognizing revenue for each of these obligations as they are satisfied. Expenses are no longer deferred, with the exception of certain commission expense, but are recognized as incurred. Since revenue and expense are recognized in earlier stages of the contract, the balance sheet accounts for deferred revenue and costs have declined upon adoption of Topic 606. Due to the complexity of certain contracts, the revenue recognition treatment under Topic 606 is dependent on contract-specific terms and may vary in some instances.

Listing Services. Under accounting policies prior to the adoption of Topic 606, amounts received for initial listing fees and listing of additional shares fees were generally deferred and revenue was recognized over estimated service periods of six and four years, respectively. Under Topic 606, we have identified the performance obligations associated with these services and are recording revenue upon satisfaction of each performance obligation. Under Topic 606, we recognize initial listing fees over a shorter period on average than the prior estimated service period. Since we recognize revenues earlier under Topic 606, the balance sheet account for deferred revenue has declined upon adoption.

The following are key items to note regarding the accounting for our Market Technology and Listing Services businesses under Topic 606:


•	revenue recognition for existing and new contracts is recognized in earlier stages under the new standard;


•	expense recognition for Market Technology contracts is recognized in earlier stages under the new standard;


•	a portion of revenues and expenses that were previously deferred were recognized either in prior period revenues, through restatement, or as an adjustment to retained earnings upon adoption of the new standard; and


•	the overall value of our contracts and the timing of cash flows from customers did not change.

The following tables present the expected effect of the adoption of Topic 606 on our Consolidated Statements of Income for the years ended December 31, 2017 and 2016:



	Year Ended December 31, 2017							Year Ended December 31, 2016
	As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted		As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted
	(in millions)							(in millions)
Revenues less transaction-based expenses:
Market Services	$	881	$	—		$	881	$	827	$	—		$	827
Corporate Services	656		(3		)	653		635		(3		)	632
Information Services	588		—			588		540		—			540
Market Technology	303		(14		)	289		275		2			277
Total revenues less transaction-based expenses	2,428		(17		)	2,411		2,277		(1		)	2,276

Total operating expenses ⁽¹⁾	1,429		(9		)	1,420		1,438		2			1,440

Income before income taxes	880		(8		)	872		136		(3		)	133
Income tax provision (benefit)	146		(3		)	143		28		(1		)	27
Net income attributable to Nasdaq	$	734	$	(5	)	$	729	$	108	$	(2	)	$	106
Diluted earnings per share	$	4.33	$	(0.03	)	$	4.30	$	0.64	$	(0.01	)	$	0.63

____________

⁽¹⁾ Adjustment to reflect the adoption of Topic 606 for the year ended December 31, 2017 and 2016 primarily pertains to our Market Technology business.

As of January 1, 2016, as the result of the adoption of Topic 606, the impact to retained earnings was immaterial. The following table presents the effect of the adoption on our Consolidated Balance Sheets as of December 31, 2017 and 2016:



	December 31, 2017							December 31, 2016
	As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted		As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted
	(in millions)							(in millions)
Assets:
Other current assets	$	187	$	(19	)	$	168	$	167	$	(15	)	$	152
Other non-current assets	412		(38		)	374		390		(46		)	344
Deferred tax assets	391		2			393		717		(1		)	716
Total assets	$	15,786	$	(55	)	$	15,731	$	14,150	$	(62	)	$	14,088

Liabilities:
Deferred revenue	$	189	$	(28	)	$	161	$	162	$	(24	)	$	138
Non-current deferred revenue	146		(20		)	126		171		(36		)	135
Total liabilities	$	9,899	$	(48	)	$	9,851	$	8,720	$	(60	)	$	8,660

Nasdaq stockholders' equity:
Retained earnings	$	3,970	$	(7	)	$	3,963	$	3,479	$	(2	)	$	3,477
Total Nasdaq stockholders' equity	5,887		(7		)	5,880		5,430		(2		)	5,428
Total liabilities and equity	$	15,786	$	(55	)	$	15,731	$	14,150	$	(62	)	$	14,088

Restructuring Charges

12 Months Ended

Dec. 31, 2017

Restructuring and Related Activities [Abstract]

Restructuring Charges

2015 Restructuring Plan

During the first quarter of 2015, we performed a comprehensive review of our processes, businesses and systems in a company-wide effort to improve performance, cut costs, and reduce spending. In June 2016, we completed our 2015 restructuring plan and recognized total net pre-tax charges of $213 million for the period March 2015 through June 2016.

The following table presents a summary of restructuring plan charges in the Consolidated Statements of Income:



	Year Ended December 31,
	2016		2015
	(in millions)
Rebranding of trade name	$	—	$	119
Severance	22		25
Facilities-related	1		—
Asset impairments	8		18
Other	10		10
Total restructuring charges	$	41	$	172

For the year ended December 31, 2016, we recognized restructuring charges totaling $41 million, including severance costs of $22 million related to workforce reductions of 201 positions across our organization, $8 million for asset impairments, primarily related to fixed assets and capitalized software that were retired, and $10 million of other charges. For the year ended December 31, 2015, we recorded restructuring charges totaling $172 million, including rebranding of our trade name of $119 million, severance costs of $25 million related to workforce reductions of 230 positions across our organization, $18 million for asset impairments, primarily related to fixed assets and capitalized software that were retired, and $10 million of other charges.

Restructuring Reserve

Severance

As of December 31, 2016, an accrued severance balance of $17 million was included in other current liabilities in the Consolidated Balance Sheets and was paid during 2017.

Acquisitions

12 Months Ended

Dec. 31, 2017

Business Combinations [Abstract]

Acquisitions

We completed the following acquisitions in 2017, 2016 and 2015. Financial results of each transaction are included in our Consolidated Statements of Income from the date of each acquisition.

2017 Acquisitions



	Purchase Consideration		Total Net Liabilities Acquired			Total Net Deferred Tax Liability			Acquired Intangible Assets		Goodwill
	(in millions)
eVestment	$	744	$	(10	)	$	(104	)	$	405	$	453

The amounts in the table above represent the preliminary allocation of purchase price as of December 31, 2017 and are subject to revision during the remainder of the measurement period, a period not to exceed 12 months from the acquisition date. Adjustments to the provisional values, which may include tax and other estimates, during the measurement period will be recorded in the reporting period in which the adjustment amounts are determined. Changes to amounts recorded as assets and liabilities may result in a corresponding adjustment to goodwill.

See “Intangible Assets” below for further discussion of intangible assets acquired in the eVestment acquisition.

Acquisition of eVestment

In October 2017, we acquired eVestment for $705 million. The aggregate cash consideration of $744 million, which is net of cash acquired of $22 million, included $39 million of estimated tax benefits associated with the transaction. We acquired net liabilities, at fair value, totaling $10 million and we recorded a net deferred tax liability of $104 million, which is net of the $39 million in estimated tax benefits associated with the transaction. The deferred tax liability recorded of $143 million relates to differences in the U.S. GAAP and tax basis of our investment in eVestment. eVestment is part of our Information Services segment.

Nasdaq used cash on hand and issuances of commercial paper to fund this acquisition.

Acquisition of Sybenetix

In September 2017, we acquired Sybenetix for an immaterial amount. Sybenetix is part of our Market Technology segment.

2016 Acquisitions



	Purchase Consideration		Total Net Assets (Liabilities) Acquired			Total Net Deferred Tax Liability			Acquired Intangible Assets		Goodwill
	(in millions)
ISE	$	1,070	$	83		$	(185	)	$	623	$	549
Boardvantage	242		28			(38		)	111		141
Marketwired	111		(1		)	(5		)	31		86
Nasdaq Canada	116		6			(20		)	76		54

The amounts in the table above represent the final allocation of purchase price for each acquisition. The allocations of the purchase price were subject to revision during the measurement period, a period not to exceed 12 months from the acquisition date. Adjustments to the provisional values, which may include tax and other estimates, during the measurement period are recorded in the reporting period in which the adjustment amounts are determined. We finalized the allocation of the purchase price for Marketwired and Nasdaq Canada in February 2017. In the second quarter of 2017, we finalized the allocation of the purchase price for Boardvantage and ISE. There were no adjustments to the provisional values during the 12-month measurement period for Nasdaq Canada and ISE. In the second quarter of 2016, we recorded a measurement period adjustment of $5 million related to our acquisition of Marketwired which is discussed below under “Acquisition of Marketwired.” In the second quarter of 2017, we recorded a measurement period adjustment of $7 million related to our acquisition of Boardvantage which is discussed below under “Acquisition of Boardvantage.”

See “Intangible Assets” below for further discussion of intangible assets acquired through our 2016 acquisitions.

Acquisition of ISE

In June 2016, we acquired ISE for $1,070 million. We acquired net assets, at fair value, totaling $83 million and recorded a net deferred tax liability of $185 million, comprised of a deferred tax liability of $266 million and a deferred tax asset of $81 million, related to differences in the U.S. GAAP and tax basis of our investment in ISE. ISE is part of our Market Services, Information Services and Market Technology segments.

In May 2016, we issued the 2023 Notes and in June 2016, we issued the 2026 Notes to fund this acquisition. See “1.75% Senior Unsecured Notes,” and “3.85% Senior Unsecured Notes,” of Note 10, “Debt Obligations,” for further discussion.

Acquisition of Boardvantage

In May 2016, we acquired Boardvantage for $242 million ($197 million in cash paid plus $45 million in working capital adjustments, which primarily includes cash acquired). We acquired net assets, at fair value, totaling $28 million and recorded a net deferred tax liability of $45 million, comprised of a deferred tax liability of $46 million and a deferred tax asset of $1 million, related to differences in the U.S. GAAP and tax basis of our investment in Boardvantage. In the second quarter of 2017, we recorded a measurement period adjustment of $7 million to the estimated fair value of deferred tax assets to reflect a revised assessment following the receipt of new information. The adjustment resulted in an increase to deferred tax assets recorded and a decrease to goodwill. The adjustment did not result in an impact to our Consolidated Statements of Income. Boardvantage is part of our Corporate Solutions business within our Corporate Services segment.

Nasdaq borrowed $197 million under the revolving credit commitment of a previous credit facility to fund this acquisition.

Acquisition of Marketwired

In February 2016, we acquired Marketwired for $111 million ($109 million in cash paid plus $2 million in working capital adjustments). We acquired net liabilities, at fair value, totaling $1 million and recorded a deferred tax liability of $10 million related to differences in the U.S. GAAP and tax basis of our investment in Marketwired. In the second quarter of 2016, we recorded a measurement period adjustment of $5 million to the estimated fair value of deferred tax liabilities to reflect a revised assessment following the receipt of new information. The adjustment resulted in a decrease to both deferred tax liabilities recorded and goodwill. The adjustment did not result in an impact to our Consolidated Statements of Income. Marketwired is part of our Corporate Solutions business within our Corporate Services segment.

Nasdaq borrowed $109 million under the revolving credit commitment of a previous credit facility to fund this acquisition.

Acquisition of Nasdaq Canada

In February 2016, we acquired Nasdaq Canada for $116 million ($115 million in cash paid plus $1 million in working capital adjustments). We acquired net assets, at fair value, totaling $6 million and recorded a deferred tax liability of $20 million related to differences in the U.S. GAAP and tax basis of our investment in Nasdaq Canada. Nasdaq Canada is part of our Market Services segment and our Data Products business within our Information Services segment.

Nasdaq used cash on hand and borrowed $55 million under the revolving credit commitment of a previous credit facility to fund this acquisition.

2015 Acquisitions



	Purchase Consideration		Total Net Assets Acquired		Total Net Deferred Tax Liability			Acquired Intangible Assets		Goodwill
	(in millions)
DWA	$	226	$	8	$	(34	)	$	141	$	111

We finalized the allocation of the purchase price for DWA in January 2016. There were no adjustments to the provisional values for this acquisition during the 12-month measurement period.

See “Intangible Assets” below for further discussion of intangible assets acquired in the DWA acquisition.

Acquisition of DWA

In January 2015, we completed the acquisition of DWA for $226 million ($225 million cash paid plus $1 million in working capital adjustments). We acquired net assets, at fair value, totaling $8 million and recorded a deferred tax liability of $34 million related to differences in the U.S. GAAP and tax basis of our investment in DWA. DWA is part of our Data Products and Index Licensing and Services businesses within our Information Services segment.

Nasdaq used cash on hand and borrowed $100 million under the revolving credit commitment of a previous credit facility to fund this acquisition.

Acquisition of Full Ownership of NPM and Acquisition of SecondMarket

In October 2015, we acquired full ownership of NPM following the acquisition of the minority stake that was previously held by a third party. In addition, through NPM, we acquired SecondMarket. The additional ownership interest in NPM and SecondMarket were purchased for an immaterial amount. NPM and SecondMarket are part of our Listing Services business within our Corporate Services segment.

* * * * * *

Intangible Assets

The following table presents the details of acquired intangible assets at the date of each acquisition. All acquired intangible assets with finite lives are amortized using the straight-line method.



	2017			2016												2015
	eVestment			ISE			Boardvantage			Marketwired			Nasdaq Canada			DWA
				($ in millions)
Intangible Assets
Exchange registrations	$	—		$	467		$	—		$	—		$	—		$	—
Discount rate used	—			8.6		%	—			—			—			—
Estimated average useful life	—			Indefinite			—			—			—			—
Customer relationships	$	378		$	148		$	103		$	29		$	76		$	29
Discount rate used	9.3		%	9.1		%	15.5		%	16.4		%	10.3		%	17.5		%
Estimated average useful life	14 years			13 years			14 years			6 years			17 years			15 years
Trade name	$	13		$	8		$	2		$	2		$	—		$	108
Discount rate used	9.2		%	8.6		%	15.0		%	15.8		%	—			17.0		%
Estimated average useful life	8 years			Indefinite			1 year			2 years			—			Indefinite
Technology	$	14		$	—		$	6		$	—		$	—		$	4
Discount rate used	9.2		%	—			15.5		%	—			—			17.0		%
Estimated average useful life	8 years			—			5 years			—			—			5 years
Total intangible assets	$	405		$	623		$	111		$	31		$	76		$	141

Exchange Registrations

As part of our acquisition of ISE we acquired exchange registrations. The exchange registrations represent licenses that provide ISE with the ability to operate its options exchanges. Nasdaq views these intangible assets as a perpetual license to operate the exchanges so long as ISE meets its regulatory requirements. Nasdaq selected a variation of the income approach called the Greenfield Approach to value the exchange registrations. The Greenfield Approach refers to a discounted cash flow analysis that assumes the buyer is building the exchange from a start-up business to a normalized level of operations as of the acquisition date. This discounted cash flow model considers the required resources and eventual returns from the build-out of operational exchanges and the acquisition of customers, once the exchange registrations are obtained. The advantage of this approach is that it reflects the actual expectations that will arise from an investment in the registrations and it directly values the registrations. The Greenfield Approach relies on assumptions regarding projected revenues, margins, capital expenditures, depreciation, and working capital during the two year pre-trade phase, the 10 year ramp-up period, as well as the terminal period.

In developing a discount rate for the exchange registrations, we estimated a weighted-average cost of capital for the overall business and we employed this rate when discounting the cash flows. The resulting discounted cash flows were then tax-effected at the applicable statutory rate.

Customer Relationships

As part of all of our 2017, 2016 and 2015 acquisitions, we acquired customer relationships. Customer relationships represent the non-contractual and contractual relationships with customers.

Methodology

For our acquisitions of eVestment, ISE, Boardvantage, Marketwired and Nasdaq Canada, customer relationships were valued using the income approach, specifically an excess earnings method. The excess earnings method examines the economic returns contributed by the identified tangible and intangible assets of a company, and then isolates the excess return that is attributable to the intangible asset being valued.

The DWA customer relationships were valued individually for each of DWA’s businesses using the income approach, specifically the with-and-without method. The with-and-without method is commonly used when the cash flows of a business can be estimated with and without the asset in place. The premise associated with this valuation technique is that the value of an asset is represented by the differences in the subject business’ cash flows under scenarios where (a) the asset is present and is used in operations (with); and (b) the asset is absent and not used in operations (without). Cash flow differentials are then discounted to present value to arrive at an estimate of fair value for the asset.

We estimated that without current customer relationships, it would take approximately 3-6 years, depending on the business, for the customer base to grow to 100.0% of current projected revenues. We also made estimates related to compensation levels and other expenses such as sales and marketing that would be incurred as the business was ramped up through the year in which the customer base would be expected to reach the level that currently exists.

Discount rate

The discount rates used reflect the amount of risk associated with the hypothetical cash flows for the customer relationships relative to the overall business. In developing a discount rate for the customer relationships, we estimated a weighted-average cost of capital for the overall business and we employed this rate when discounting the cash flows. The resulting discounted cash flows were then tax-effected at the applicable statutory rate.

For our acquisitions of eVestment, Marketwired, Nasdaq Canada, and DWA a discounted tax amortization benefit was added to the fair value of the assets under the assumption that the customer relationships would be amortized for tax purposes over a period of 15 years.

Estimated Useful Life

We estimate the useful life based on the historical behavior of the customers and a parallel analysis of the customers using the excess earnings method.

Trade Names

As part of our acquisitions of eVestment, ISE, and DWA, we acquired trade names. These trade names are recognized in their respective industries and carry a reputation for quality. As such, the reputation and positive recognition embodied in these trade names are valuable assets to Nasdaq.

eVestment and ISE Trade Names

The eVestment and ISE trade names were valued using the income approach, specifically the relief-from-royalty method, or RFRM. The RFRM is used to estimate the cost savings that accrue to the owner of an intangible asset who would otherwise have to pay royalties or license fees on revenues earned through the use of the asset. The royalty rate is applied to the projected revenue over the expected remaining life of the intangible asset to estimate royalty savings. The net after-tax royalty savings are calculated for each year in the remaining economic life of the trade name and discounted to present value.

The discount rates used reflect the amount of risk associated with the hypothetical cash flows for each trade name relative to the overall business as discussed above in “Customer Relationships.”

We have estimated the useful life of the eVestment trade name to be 8 years and the estimated useful life of the ISE trade name to be indefinite based on the number of years the name has been in service, its popularity within the industry, and our intention to continue to use it in the branding of products.

DWA Trade Name

The DWA trade name was considered the primary asset acquired in the DWA transaction. In valuing the acquired trade name, we used the income approach, specifically the excess earnings method. The excess earnings method examines the economic returns contributed by the identified tangible and intangible assets of a company, and then isolates the excess return that is attributable to the intangible asset being valued.

The discount rate used reflects the amount of risk associated with the hypothetical cash flows generated by the DWA trade name in the future. In developing a discount rate for the trade name, we estimated a weighted average cost of capital for the overall business and we employed this rate when discounting the cash flows. The resulting discounted cash flows were then tax-effected at the applicable statutory rate, and a discounted tax amortization benefit was added to the fair value of the asset under the assumption that the trade name would be amortized for tax purposes over a period of 15 years.

We estimated the useful life of the trade name to be indefinite. The useful life was based on several factors including the number of years the name has been in service, its popularity within the industry, and our intention to continue its use in the branding of products.

Technology

As part of our acquisitions of eVestment, Boardvantage, and DWA, we acquired developed technology.

Methodology

The developed technologies were valued using the income approach, specifically the RFRM as discussed above in “Trade Names.”

Discount rate

The discount rates used reflect the amount of risk associated with the hypothetical cash flows for each developed technology relative to the overall business as discussed above in “Customer Relationships.”

Estimated Useful Life

We have estimated the useful life of the eVestment technology to be 8 years and the estimated useful life of the Boardvantage technology and DWA technology to be 5 years.

Pro Forma Results and Acquisition-related Costs

The consolidated financial statements for the years ended December 31, 2017, 2016 and 2015 include the financial results of the above 2017, 2016 and 2015 acquisitions from the date of each acquisition. Pro forma financial results for acquisitions completed in 2017, 2016 and 2015 have not been presented since these acquisitions both individually and in the aggregate were not material to our financial results.

Acquisition-related costs for the transactions described above were expensed as incurred and are included in merger and strategic initiatives expense in the Consolidated Statements of Income.

Assets and Liabilities Held For Sale Assets and Liabilities Held For Sale

12 Months Ended

Dec. 31, 2017

Discontinued Operations and Disposal Groups [Abstract]

Assets and Liabilities Held For Sale

We classify assets and liabilities as held for sale (disposal group) when management, having the authority to approve the action, commits to a plan to sell the disposal group, the sale is probable within one year, and the disposal group is available for immediate sale in its present condition. We also consider whether an active program to locate a buyer has been initiated, whether the disposal group is marketed actively for sale at a price that is reasonable in relation to its current fair value, and whether actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. We initially measure a disposal group that is classified as held for sale at the lower of its carrying amount or fair value less costs to sell. Any loss resulting from this measurement is recognized in the period in which the held for sale criteria are met. Conversely, gains are not recognized until the date of sale. We assess the fair value of a disposal group less costs to sell each reporting period it remains classified as held for sale and report any subsequent changes as an adjustment to the carrying amount of the disposal group, as long as the new carrying amount does not exceed the carrying amount of the disposal group at the time it was initially classified as held for sale. Assets are not depreciated or amortized while they are classified as held for sale. Upon determining that a disposal group meets the criteria to be classified as held for sale, we report the assets and liabilities of the disposal group as assets held for sale and liabilities held for sale in our Consolidated Balance Sheets.

In September 2017, we commenced a process to evaluate strategic alternatives for our Public Relations Solutions and Digital Media Services businesses within our Corporate Solutions business as part of our strategic refinement. The Corporate Solutions business is part of our Corporate Services segment. The Public Relations Solutions and Digital Media Services businesses include the following products and services:


•	Nasdaq GlobeNewswire;


•	Nasdaq Influencers;


•	Nasdaq Media Intelligence;


•	Nasdaq IR Websites and Newsrooms; and


•	Nasdaq Webcasts.

As a result of the above, we determined that we met all of the criteria to classify the assets and liabilities of these businesses as held for sale as of September 30, 2017. The disposal of these businesses did not represent a strategic shift that would have a major effect on our operations and financial results and is, therefore, not classified as discontinued operations. No impairment charge was recorded for the year ended December 31, 2017 as the carrying amount of the net assets was less than the fair value less costs to sell. Fair value was determined based upon the anticipated sales price of these businesses based on current market conditions and assumptions made by management, which may differ from actual results and may result in an impairment if market conditions deteriorate. In January 2018, we announced that we entered into a definitive agreement to sell our Public Relations Solutions and Digital Media Services businesses. Based on the sales price in the agreement, no impairment charge was recorded. See “Definitive Agreement to Sell our Public Relations Solutions and Digital Media Services Businesses,” of Note 21, “Subsequent Events,” for further discussion.

The following table presents the carrying amounts of the major classes of assets and liabilities classified as held for sale in the Consolidated Balance Sheets:



	December 31, 2017
	(in millions)
Receivables, net	$	27
Property and equipment, net	21
Goodwill⁽¹⁾	202
Intangible assets, net	38
Other assets	9
Total assets held for sale	$	297

Deferred tax liabilities	$	16
Other current liabilities	29
Total liabilities held for sale	$	45

____________

⁽¹⁾ The assignment of goodwill was based on the relative fair value of the disposal group and the portion of the remaining reporting unit.

Goodwill and Acquired Intangible Assets

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Acquired Intangible Assets

Goodwill

The following table presents the changes in goodwill by business segment during the year ended December 31, 2017:



	Market Services		Corporate Services			Information Services		Market Technology		Total
	(in millions)
Balance at December 31, 2016	$	3,390	$	674		$	1,806	$	157	$	6,027
Goodwill acquired	—		—			453		13		466
Measurement period adjustment	—		(7		)	—		—		(7		)
Foreign currency translation adjustment	156		25			103		18		302
Goodwill reclassified as held for sale⁽¹⁾	—		(202		)	—		—		(202		)
Balance at December 31, 2017	$	3,546	$	490		$	2,362	$	188	$	6,586

____________

⁽¹⁾ See Note 5, “Assets and Liabilities Held for Sale,” for further discussion.

The goodwill acquired for Information Services shown above relates to our acquisition of eVestment, and the goodwill acquired for Market Technology shown above relates to our acquisition of Sybenetix. See “2017 Acquisitions,” of Note 4, “Acquisitions,” for further discussion.

In the second quarter of 2017, we recorded a measurement period adjustment of $7 million to the estimated fair value of deferred tax assets related to our acquisition of Boardvantage. See “Acquisition of Boardvantage,” of Note 4, “Acquisitions,” for further discussion of the Boardvantage acquisition. The adjustment was made to reflect a revised assessment of deferred tax assets following the receipt of new information. The adjustment resulted in an increase to deferred tax assets recorded and a decrease to goodwill and is reflected in the above table. The measurement period adjustment is included in our Consolidated Balance Sheets as of December 31, 2017. The adjustment did not result in an impact to our Consolidated Statements of Income.

As of December 31, 2017, the amount of goodwill that is expected to be deductible for tax purposes in future periods is $864 million.

Goodwill represents the excess of purchase price over the value assigned to the net assets, including identifiable intangible assets, of a business acquired. Goodwill is allocated to our reporting units based on the assignment of the fair values of each reporting unit of the acquired company. We test goodwill for impairment at the reporting unit level annually, or in interim periods if certain events occur indicating that the carrying amount may be impaired, such as changes in the business climate, poor indicators of operating performance or the sale or disposition of a significant portion of a reporting unit. There was no impairment of goodwill for the years ended December 31, 2017, 2016 and 2015; however, events such as extended economic weakness or unexpected significant declines in operating results of a reporting unit may result in goodwill impairment charges in the future.

Acquired Intangible Assets

The following table presents details of our total acquired intangible assets, both finite- and indefinite-lived:



	December 31, 2017										December 31, 2016
	Gross Amount			Accumulated Amortization			Net Amount			Weighted-Average Useful Life (in Years)	Gross Amount			Accumulated Amortization			Net Amount			Weighted-Average Useful Life (in Years)
	(in millions)										(in millions)
Finite-Lived Intangible Assets
Technology	$	65		$	(22	)	$	43		8	$	38		$	(24	)	$	14		5
Customer relationships	1,708			(526		)	1,182			18	1,394			(464		)	930			18
Other	17			(4		)	13			8	7			(6		)	1			6
Foreign currency translation adjustment	(111		)	46			(65		)		(160		)	58			(102		)
Total finite-lived intangible assets	$	1,679		$	(506	)	$	1,173			$	1,279		$	(436	)	$	843
Indefinite-Lived Intangible Assets
Exchange and clearing registrations	$	1,257		$	—		$	1,257			$	1,257		$	—		$	1,257
Trade names	129			—			129				130			—			130
Licenses	52			—			52				52			—			52
Foreign currency translation adjustment	(143		)	—			(143		)		(188		)	—			(188		)
Total indefinite-lived intangible assets	$	1,295		$	—		$	1,295			$	1,251		$	—		$	1,251
Total intangible assets	$	2,974		$	(506	)	$	2,468			$	2,530		$	(436	)	$	2,094

As a result of our decision to evaluate strategic alternatives for our Public Relations Solutions and Digital Media Services businesses within our Corporate Solutions business, we reclassified certain intangibles assets to held for sale. The following table presents the gross amount, accumulated amortization and net amount of finite-lived and indefinite-lived intangible assets that have been reclassified as assets held for sale as of December 31, 2017. See Note 5, “Assets and Liabilities Held for Sale,” for further discussion.



	Gross Amount		Accumulated Amortization			Net Amount
	(in millions)
Finite-lived intangible assets reclassified as held for sale:
Customer relationships	$	54	$	(17	)	$	37
Other	2		(1		)	1
Total finite-lived intangible assets held for sale	$	56	$	(18	)	$	38

In January 2018, we announced that we entered into a definitive agreement to sell our Public Relations Solutions and Digital Media Services businesses. See “Definitive Agreement to Sell our Public Relations Solutions and Digital Media Services Businesses,” of Note 21, “Subsequent Events,” for further discussion.

Amortization expense for acquired finite-lived intangible assets was $92 million for the year ended December 31, 2017, $82 million for the year ended December 31, 2016, and $62 million for the year ended December 31, 2015. Amortization expense increased in 2017 and 2016 primarily due to additional amortization expense associated with acquired intangible assets. The increase in 2017 was associated with our 2017 and 2016 acquisitions and the increase in 2016 was primarily associated with our 2016 acquisitions. These amounts are included in depreciation and amortization expense in the Consolidated Statements of Income.

The estimated future amortization expense (excluding the impact of foreign currency translation adjustments of $65 million as of December 31, 2017) of acquired finite-lived intangible assets as of December 31, 2017 is as follows:



	(in millions)
2018	$	114
2019	99
2020	99
2021	97
2022	94
2023 and thereafter	735
Total	$	1,238

Intangible Asset Impairment Charges

We recorded pre-tax, non-cash intangible asset impairment charges described below during 2016 and 2015.

During 2016, the eSpeed business operated in a challenging environment and, as a result, experienced a decline in operating performance. In late 2016, the management team conducted an extensive business review of the eSpeed business. Based upon this review, management changed the strategic direction of our Fixed Income business and more closely integrated the U.S. and European Fixed Income businesses under a single brand called Nasdaq Fixed Income. As part of this effort, we decided to no longer utilize the eSpeed trade name. In connection with these triggering events, following board approval in January 2017, we recorded a pre-tax, non-cash intangible asset impairment charge of $578 million to write off the full value of the eSpeed trade name as we no longer attributed any material value to the trade name. This charge is recorded in asset impairment charge in the Consolidated Statements of Income for 2016.

In 2015, in connection with our global rebranding initiative, we decided to change our company name from The NASDAQ OMX Group, Inc. to Nasdaq, Inc., which became effective in the third quarter of 2015. In connection with this action, we decided to discontinue the use of the OMX trade name and recorded a pre-tax, non-cash impairment charge of $119 million because we no longer attributed any material value to the trade name. This charge is recorded in restructuring charges in the Consolidated Statements of Income for 2015.

These intangible asset impairment charges did not impact the company’s consolidated cash flows, liquidity, or capital resources and related primarily to our Market Services segment. However, for segment reporting purposes, these charges were allocated to corporate items based on the decision that these charges should not be used to evaluate any particular segment’s operating performance.

Significant judgments and unobservable inputs categorized as Level III in the fair value hierarchy are inherent in impairment tests performed and include assumptions about the amount and timing of expected future cash flows, growth rates and the determination of appropriate discount rates. We believe that the assumptions used in our impairment tests are reasonable, but variations in any of the assumptions could result in different calculations of fair value.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Investments

12 Months Ended

Dec. 31, 2017

Investments, Debt and Equity Securities [Abstract]

Investments

The following table presents the details of our investments:



	December 31, 2017		December 31, 2016
	(in millions)
Trading securities	$	221	$	228
Available-for-sale investment securities	14		17
Equity method investments	131		124
Cost method investments	$	152	$	144

Trading Securities

Trading securities, which are included in financial investments, at fair value in the Consolidated Balance Sheets, are primarily comprised of highly rated European government debt securities, of which $160 million as of December 31, 2017 and $172 million as of December 31, 2016, are assets utilized to meet regulatory capital requirements, primarily for our clearing operations at Nasdaq Clearing.

Available-for-Sale Investment Securities

As of December 31, 2017, available-for-sale investment securities, which are included in financial investments, at fair value in the Consolidated Balance Sheets, are primarily comprised of commercial paper. As of December 31, 2016, available-for-sale investment securities were primarily comprised of short-term certificates of deposit and commercial paper. As of December 31, 2017 and December 31, 2016, the cumulative unrealized gains and losses on these securities were immaterial.

Equity Method Investments

As of December 31, 2017 and December 31, 2016, our equity method investments primarily included equity interests in OCC and EuroCCP N.V.

The carrying amounts of our equity method investments are included in other non-current assets in the Consolidated Balance Sheets.

Net income recognized from our equity interest in the earnings and losses of these equity method investments was $15 million for the year ended December 31, 2017, $2 million for the year ended December 31, 2016 and $17 million for the year ended December 31, 2015. The change in the year ended December 31, 2017 compared with the same period in 2016 relates to our additional 20.0% ownership interest in OCC, which we acquired in connection with our acquisition of ISE in June 2016, bringing our total ownership interest in OCC to 40.0%, partially offset by $2 million of wind down costs associated with an equity method investment that was previously written off. The change in the year ended December 31, 2016 compared with the same period in 2015 is primarily due to income recognized from our equity method investment in OCC, partially offset by the write-off of our equity method investment in The Order Machine. We were not able to determine what our share of OCC’s income was for the year ended December 31, 2014 until the first quarter of 2015, when financial statements were made available to us. As a result, we recorded other income of $13 million in the first quarter of 2015 relating to our share of OCC’s income for the year ended December 31, 2014.

As of December 31, 2016, the estimated fair value of our investment in The Order Machine was less than the carrying value and management considered the decline in value to be other-than-temporary. As a result, we recorded a pre-tax, non-cash impairment charge of $7 million to write off the full value of this investment. This charge is partially offset by a gain resulting from the sale of a percentage of a separate equity method investment and is recorded in net income from unconsolidated investees in the Consolidated Statements of Income for 2016. No other impairments of equity method investments were recorded in 2017, 2016 or 2015.

Capital Contribution to OCC

In March 2015, in connection with being designated systemically important by the Financial Stability Oversight Council, OCC implemented a capital plan under which the options exchanges that are OCC’s stockholders made new capital contributions to OCC, committed to make further capital contributions in the future under certain specified circumstances, and received certain commitments from OCC with respect to future dividend payments and related matters. Under the OCC capital plan, OCC’s existing exchange stockholders, including Nasdaq and ISE, each contributed a pro-rata share of $150 million in new equity capital. Nasdaq’s and ISE’s capital contributions were each $30 million. OCC’s exchange stockholders also committed to provide, as may become necessary from time to time, additional replenishment capital on a pro-rata basis if certain capital thresholds are triggered. For its part, OCC adopted specific policies with respect to fees, customer refunds and stockholder dividends, which envision an annual dividend payment to its stockholders equal to the portion of OCC’s after-tax income that exceeds OCC’s capital requirements after payment of refunds to OCC’s clearing members (with such customer refunds generally to constitute 50% of the portion of OCC’s pre-tax income that exceeds OCC’s capital requirements).

After the SEC staff approved the OCC capital plan and the stockholders made their capital contributions, the plan’s further effectiveness was suspended under the applicable SEC rules because certain parties petitioned the full Commission to reconsider the capital plan’s approval. This stay was lifted by the SEC in September 2015, allowing OCC to implement the plan and in February 2016, the SEC issued an order approving the OCC capital plan as previously implemented and dismissed the petitions challenging that plan. The petitioners filed for a stay of the SEC’s order, which would have blocked OCC from paying a dividend under the OCC capital plan. The Federal Court of Appeals for the District of Columbia Circuit, or the Court of Appeals, denied the requested stay, permitting OCC to pay a dividend which Nasdaq received in February 2016.

The petitioners also appealed the SEC’s order to the Court of Appeals. The Court of Appeals heard arguments on the case in March 2017 and decided the case in August 2017. The Court of Appeals remanded the case to the SEC for further examination of the record and an independent assessment by the SEC of the evidence OCC submitted. The Court directed that the SEC approval of the OCC capital plan remain in place during the SEC’s examination unless the SEC determined not to preserve it. The SEC has allowed OCC to preserve the capital plan, and in September 2017, OCC disbursed an annual dividend of $5 million per ownership share. Nasdaq, as the owner of two shares, received $10 million. The SEC provided OCC and the appellants with an opportunity to submit further briefs and evidence for the administrative record. It appears from public filings that the SEC record is complete and that the matter is now under consideration by the agency. There has been no ruling at this time, and there is no deadline for the SEC to issue its ruling.

Cost Method Investments

The carrying amounts of our cost method investments are included in other non-current assets in the Consolidated Balance Sheets. As of December 31, 2017 and December 31, 2016, our cost method investments primarily represented our 5% ownership interest in Borsa İstanbul, and our 5% ownership interest in LCH.Clearnet Group Limited.

The Borsa Istanbul shares, which were issued to us in the first quarter of 2014, are part of the consideration received under a market technology agreement. This investment has a cost basis of $75 million which is guaranteed to us via a put option negotiated as part of the market technology agreement.

Property and Equipment, net

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Property and Equipment, net

The following table presents our major categories of property and equipment, net:



	Year Ended December 31,
	2017			2016
	(in millions)
Data processing equipment and software	$	626		$	665
Furniture, equipment and leasehold improvements	279			254
Total property and equipment	905			919
Less: accumulated depreciation and amortization	(505		)	(557		)
Total property and equipment, net	$	400		$	362

Depreciation and amortization expense for property and equipment was $96 million for the year ended December 31, 2017, $88 million for the year ended December 31, 2016 and $76 million for the year ended December 31, 2015. The increase in depreciation and amortization expense in 2017 and 2016 was primarily due to additional expense associated with assets and software placed in service. These amounts are included in depreciation and amortization expense in the Consolidated Statements of Income.

We recorded asset impairment charges of $9 million for the year ended December 31, 2017, $8 million for the year ended December 31, 2016 and $18 million for the year ended December 31, 2015. The asset impairment charge in 2017 primarily related to the write-off of capitalized software and hardware equipment associated with our 2017 and 2016 acquisitions and is included in merger and strategic initiatives expense in the Consolidated Statements of Income. The asset impairment charges in 2016 and 2015 primarily related to fixed assets and capitalized software that were retired. The 2016 and 2015 asset impairment charges are included in restructuring charges in the Consolidated Statements of Income for the respective periods.

As of December 31, 2017 and 2016, we did not own any real estate properties.

Deferred Revenue

12 Months Ended

Dec. 31, 2017

Deferred Revenue Disclosure [Abstract]

Deferred Revenue

Deferred revenue represents consideration received that is yet to be recognized as revenue. The changes in our deferred revenue during the year ended December 31, 2017 and 2016 are reflected in the following table:



	Initial Listing Revenues			Listing of Additional Shares Revenues			Annual Renewal and Other Revenues			Market Technology Revenues			Total
	(in millions)
Balance at January 1, 2017	$	54		$	37		$	57		$	185		$	333
Additions	18			11			569			208			806
Revenue recognized	(17		)	(22		)	(544		)	(240		)	(823		)
Translation adjustment	—			—			1			20			21
Deferred revenue reclassified as held for sale⁽¹⁾	—			—			(2		)	—			(2		)
Balance at December 31, 2017	$	55		$	26		$	81		$	173		$	335

Balance at January 1, 2016	$	59		$	53		$	28		$	187		$	327
Additions	13			12			606			233			864
Revenue recognized	(18		)	(28		)	(576		)	(227		)	(849		)
Translation adjustment	—			—			(1		)	(8		)	(9		)
Balance at December 31, 2016	$	54		$	37		$	57		$	185		$	333

____________

⁽¹⁾ See Note 5, “Assets and Liabilities Held for Sale,” for further discussion.

The additions and revenue recognized for initial listing revenues, listing of additional shares revenues and annual renewal and other revenues primarily reflect revenues from our Listing Services business within our Corporate Services segment.

For our market technology contracts, total revenues, as well as costs incurred, are deferred until significant customizations are completed and delivered. Once delivered, deferred revenue and the related deferred costs are recognized over the post-contract support period. For these market technology contracts, we have included the deferral of costs in other current assets and other non-current assets in the Consolidated Balance Sheets.

As of December 31, 2017, we estimate that our deferred revenue, which is primarily corporate services and market technology revenues, will be recognized in the following years:



	Initial Listing Revenues		Listing of Additional Shares Revenues		Annual Renewal and Other Revenues		Market Technology Revenues		Total
	(in millions)
Fiscal year ended:
2018	$	17	$	13	$	79	$	80	$	189
2019	15		7		2		35		59
2020	11		5		—		33		49
2021	7		1		—		15		23
2022	4		—		—		3		7
2023 and thereafter	1		—		—		7		8
	$	55	$	26	$	81	$	173	$	335

The timing of recognition of our deferred market technology revenues is primarily dependent upon the completion of customization and any significant modifications made pursuant to existing market technology contracts. As such, as it relates to market technology revenues, the timing represents our best estimate.

On January 1, 2018, we adopted ASU 2014-09, “Revenue from Contracts with Customers.” As a result, a portion of revenues that were previously deferred were recognized either in prior period revenues, through restatement, or as an adjustment to retained earnings upon adoption of the new standard. See “Recent Accounting Pronouncements,” of Note 2, “Summary of Significant Accounting Policies,” for further discussion and the impact to the deferred revenue balance.

Debt Obligations

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Debt Obligations

The following table presents the changes in the carrying amount of our debt obligations during the year ended December 31, 2017:



	December 31, 2016		Additions		Payments, Accretion and Other			December 31, 2017
	(in millions)
Short-term debt - commercial paper	$	—	$	2,514	$	(2,034	)	$	480
Long-term debt:
5.55% senior unsecured notes due January 15, 2020	598		—		1			599
5.25% senior unsecured notes repaid on May 26, 2017	369		—		(369		)	—
3.875% senior unsecured notes due June 7, 2021	625		—		91			716
4.25% senior unsecured notes due June 1, 2024	495		—		1			496
1.75% senior unsecured notes due May 19, 2023	622		—		90			712
3.85% senior unsecured notes due June 30, 2026	495		—		1			496
Senior unsecured floating rate notes due March 22, 2019	—		498		—			498
$400 million senior unsecured term loan facility due November 25, 2019 (average interest rate of 2.47% for the period January 1, 2017 through December 31, 2017)	399		—		(299		)	100
$1 billion revolving credit commitment due April 25, 2022 (average interest rate of 2.66% for the period April 25, 2017 through December 31, 2017)	—		155		(45		)	110
Total long-term debt	3,603		653		(529		)	3,727
Total debt obligations	$	3,603	$	3,167	$	(2,563	)	$	4,207

Commercial Paper Program

In April 2017, we entered into a U.S. dollar commercial paper program. The commercial paper program is supported by our 2017 Credit Facility which provides liquidity support for the repayment of commercial paper issued through the commercial paper program. See “2017 Credit Facility” below for further discussion of our 2017 Credit Facility. The effective interest rate of commercial paper issuances fluctuate as short term interest rates and demand fluctuate. The fluctuation of these rates due to market conditions may impact our interest expense.

In May 2017, we used a combination of cash on hand and net proceeds from the sale of commercial paper to redeem all of our 2018 Notes. In addition, in June 2017, we used net proceeds from the sale of commercial paper to repay $300 million of the amount outstanding on the 2016 Credit Facility. See “Early Extinguishment of 2018 Notes” and “2016 Credit Facility” below for further discussion.

In connection with our agreement to acquire eVestment, we issued the 2019 Notes. Since the proposed acquisition of eVestment was not immediately expected to close, $276 million of the net proceeds from the 2019 Notes was used to partially pay down our outstanding commercial paper balance. See “Senior Unsecured Floating Rate Notes” below for further discussion of our 2019 Notes.

As of December 31, 2017, commercial paper notes in the table above reflect the aggregate principal amount, less the unamortized discount which is being accreted through interest expense over the life of the applicable notes. The original maturities of these notes range from 12 days to 119 days and the weighted-average maturity is 22 days. The weighted-average effective interest rate is 1.70% per annum.

Senior Unsecured Notes

Our senior unsecured notes were all issued at a discount. As a result of the discount, the proceeds received from each issuance were less than the aggregate principal amount. As of December 31, 2017, the amounts in the table above reflect the aggregate principal amount, less the unamortized debt discount and the unamortized debt issuance costs which are being accreted through interest expense over the life of the applicable notes. Our senior unsecured notes are general unsecured obligations of ours and rank equally with all of our existing and future unsubordinated obligations and they are not guaranteed by any of our subsidiaries. The senior unsecured notes were issued under indentures that, among other things, limit our ability to consolidate, merge or sell all or substantially all of our assets, create liens, and enter into sale and leaseback transactions.

With the exception of the 2020 Notes, upon a change of control triggering event (as defined in the various note indentures), the terms require us to repurchase all or part of each holder’s notes for cash equal to 101% of the aggregate principal amount purchased plus accrued and unpaid interest, if any.

5.55% Senior Unsecured Notes

In January 2010, Nasdaq issued the 2020 Notes. The 2020 Notes pay interest semiannually at a rate of 5.55% per annum until January 15, 2020.

Early Extinguishment of 2018 Notes

In December 2010, Nasdaq issued the 2018 Notes. The 2018 Notes paid interest semiannually at a rate of 5.25% per annum.

In May 2017, we redeemed all of our 2018 Notes using a combination of cash on hand and net proceeds from the sale of commercial paper issued through the commercial paper program. See “Commercial Paper Program” above for further discussion of our commercial paper program. In connection with the early extinguishment of the 2018 Notes, we recorded a pre-tax charge of $9 million, which primarily included a make-whole redemption price premium. This charge is included in general, administrative and other expense in the Consolidated Statements of Income for the year ended December 31, 2017.

3.875% Senior Unsecured Notes

In June 2013, Nasdaq issued the 2021 Notes. The 2021 Notes pay interest annually at a rate of 3.875% per annum until June 7, 2021 and such rate may vary with Nasdaq’s debt rating up to a rate not to exceed 5.875%.

The 2021 Notes have been designated as a hedge of our net investment in certain foreign subsidiaries to mitigate the foreign exchange risk associated with certain investments in these subsidiaries. The increase in the carrying amount of $91 million noted in the “Payments, Accretion and Other” column in the table above primarily reflects the translation of the 2021 Notes into U.S. dollars and is recorded in accumulated other comprehensive loss within stockholders’ equity in the Consolidated Balance Sheets as of December 31, 2017.

4.25% Senior Unsecured Notes

In May 2014, Nasdaq issued the 2024 Notes. The 2024 Notes pay interest semiannually at a rate of 4.25% per annum until June 1, 2024 and such rate may vary with Nasdaq’s debt rating up to a rate not to exceed 6.25%.

1.75% Senior Unsecured Notes

In May 2016, Nasdaq issued the 2023 Notes. We used the net proceeds from the 2023 Notes and the 2026 Notes to fund our acquisition of ISE. See “Acquisition of ISE,” of Note 4, “Acquisitions,” for further discussion of the ISE acquisition.

The 2023 Notes pay interest annually at a rate of 1.75% per annum until May 19, 2023 and such rate may vary with Nasdaq’s debt rating up to a rate not to exceed 3.75%.

The 2023 Notes have been designated as a hedge of our net investment in certain foreign subsidiaries to mitigate the foreign exchange rate risk associated with certain investments in these subsidiaries. The increase in the carrying amount of $90 million noted in the “Payments, Accretion and Other” column in the table above reflects the translation of the 2023 Notes into U.S. dollars and is recorded in accumulated other comprehensive loss within stockholders’ equity in the Consolidated Balance Sheets as of December 31, 2017.

3.85% Senior Unsecured Notes

In June 2016, Nasdaq issued the 2026 Notes. We used the net proceeds from the 2023 Notes and the 2026 Notes to fund our acquisition of ISE. See “Acquisition of ISE,” of Note 4, “Acquisitions,” for further discussion of the ISE acquisition.

The 2026 Notes pay interest semiannually at a rate of 3.85% per annum until June 30, 2026 and such rate may vary with Nasdaq’s debt rating up to a rate not to exceed 5.85%.

Senior Unsecured Floating Rate Notes

In September 2017, Nasdaq issued the 2019 Notes. We used the net proceeds from the 2019 Notes to partially pay down our outstanding commercial paper balance and the remainder of the net proceeds was used to partially fund our acquisition of eVestment. See “Acquisition of eVestment,” of Note 4, “Acquisitions,” for further discussion of the eVestment acquisition.

The 2019 Notes pay interest quarterly in arrears at a rate equal to the three-month U.S. dollar LIBOR as determined at the beginning of each quarterly period plus 0.39% per annum until March 22, 2019.

Credit Facilities

As of December 31, 2017, the amounts in the table above reflect the aggregate principal amount, less the unamortized debt issuance costs which are being accreted through interest expense over the life of the applicable credit facility. Nasdaq is permitted to repay borrowings under our credit facilities at any time in whole or in part, without penalty.

Our credit facilities contain financial and operating covenants. Financial covenants include a minimum interest expense coverage ratio and a maximum leverage ratio. Operating covenants include, among other things, limitations on Nasdaq’s ability to incur additional indebtedness, grant liens on assets, dispose of assets and pay dividends. Our credit facilities allow us to pay cash dividends on our common stock. The facilities also contain customary affirmative covenants, including access to financial statements, notice of defaults and certain other material events, maintenance of properties and insurance, and events of default, including cross-defaults to our material indebtedness.

2017 Credit Facility

In April 2017, Nasdaq entered into the 2017 Credit Facility. The 2017 Credit Facility consists of a $1 billion five-year revolving credit facility (with sublimits for non-dollar borrowings, swingline borrowings and letters of credit), which replaced our 2014 credit facility. See “2014 Credit Facility” below for further discussion. Nasdaq intends to use funds available under the 2017 Credit Facility for general corporate purposes and to provide liquidity support for the repayment of commercial paper issued through the commercial paper program.

As of December 31, 2017, the balance of $110 million reflects the outstanding amount under the 2017 Credit Facility, less unamortized debt issuance costs of $5 million. Of the $885 million that is available for borrowing as of December 31, 2017, $480 million provides liquidity support for the principal amount outstanding under the commercial paper program. In addition, $1 million has been utilized for a letter of credit. As such, as of December 31, 2017, the total remaining amount available under the 2017 Credit Facility was $404 million. See “Commercial Paper Program” above for further discussion of our commercial paper program.

Under our 2017 Credit Facility, borrowings under the revolving credit facility and swingline borrowings bear interest on the principal amount outstanding at a variable interest rate based on either the LIBOR or the base rate (as defined in the credit agreement) (or other applicable rate with respect to non-dollar borrowings), plus an applicable margin that varies with Nasdaq’s debt rating.

The 2017 Credit Facility includes an option for Nasdaq to increase the available aggregate amount by up to $500 million, subject to the consent of the lenders funding the increase and certain other conditions.

2016 Credit Facility

In March 2016, Nasdaq entered into the 2016 Credit Facility. In March 2016, loans in an aggregate principal amount of $400 million were drawn under the 2016 Credit Facility and the net proceeds were used to partially repay amounts outstanding under the revolving credit commitment of the 2014 credit facility. See “2014 Credit Facility” below for further discussion of our 2014 credit facility.

Under our 2016 Credit Facility, borrowings bear interest on the principal amount outstanding at a variable interest rate based on either the LIBOR or the base rate (or other applicable rate with respect to non-dollar borrowings), plus an applicable margin that varies with Nasdaq’s debt rating.

In June 2017, we used net proceeds from the sale of commercial paper issued through the commercial paper program to repay $300 million of the amount outstanding on the 2016 Credit Facility. The remaining amount outstanding of $100 million is due upon maturity at November 25, 2019. See “Commercial Paper Program” above for further discussion of our commercial paper program. In connection with the partial repayment of the amount outstanding on the 2016 Credit Facility, we recorded a pre-tax charge of $1 million which related to the write-off of unamortized debt issuance costs related to the $300 million payment. This charge is included in general, administrative and other expense in the Consolidated Statements of Income for the year ended December 31, 2017.

2014 Credit Facility

In November 2014, Nasdaq entered into the 2014 credit facility. The 2014 credit facility consisted of a $750 million revolving credit commitment (with sublimits for non-dollar borrowings, swingline borrowings and letters of credit).

Loans under the 2014 credit facility had a variable interest rate based on either the LIBOR or the base rate (as defined in the credit agreement) (or other applicable rate with respect to non-dollar borrowings), plus an applicable margin that varied with Nasdaq’s debt rating.

In April 2017, Nasdaq entered into the 2017 Credit Facility which replaced the 2014 credit facility. As a result, our 2014 credit facility has been terminated. No amounts were outstanding on the 2014 credit facility during 2017. See “2017 Credit Facility” above for further discussion of our 2017 Credit Facility.

Other Credit Facilities

We also have credit facilities related to our Nasdaq Clearing operations in order to provide further liquidity. Credit facilities, which are available in multiple currencies, totaled $187 million as of December 31, 2017 and $170 million as of December 31, 2016 in available liquidity, none of which was utilized.

Debt Covenants

As of December 31, 2017, we were in compliance with the covenants of all of our debt obligations.

Income Taxes

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Income Taxes

The income tax provision consists of the following amounts:



	Year Ended December 31,
	2017			2016			2015
	(in millions)
Current income taxes:
Federal	$	51		$	37		$	139
State	17			21			42
Foreign	68			106			36
Total current income taxes	136			164			217
Deferred income taxes:
Federal	(14		)	(97		)	(18		)
State	24			(35		)	(1		)
Foreign	—			(4		)	5
Total deferred income taxes	10			(136		)	(14		)
Total income tax provision	$	146		$	28		$	203

We have determined that undistributed earnings of certain non-U.S. subsidiaries will be reinvested for an indefinite period of time. We have both the intent and ability to indefinitely reinvest these earnings. As of December 31, 2017, the cumulative amount of undistributed earnings in these subsidiaries is approximately $131 million. Given our intent to reinvest these earnings for an indefinite period of time, we have not accrued a deferred tax liability on these earnings. A determination of an unrecognized deferred tax liability related to these earnings is not practicable.

A reconciliation of the income tax provision, based on the U.S. federal statutory rate, to our actual income tax provision for the years ended December 31, 2017, 2016 and 2015 is as follows:



	Year Ended December 31,
	2017		2016		2015
Federal income tax provision at the statutory rate	35.0	%	35.0	%	35.0	%
State income tax provision, net of federal effect	2.6	%	(6.7	)%	3.9	%
Change in deferred taxes due to change in law	(9.9	)%	(1.2	)%	0.2	%
Excess tax benefits related to employee share-based compensation	(4.0	)%	—	%	—	%
Non-U.S. subsidiary earnings	(6.0	)%	(7.3	)%	(6.4	)%
Tax credits and deductions	(1.0	)%	(5.1	)%	(0.8	)%
Change in unrecognized tax benefits	(0.8	)%	4.2	%	0.3	%
Other, net	0.7	%	1.7	%	—	%
Actual income tax provision	16.6	%	20.6	%	32.2	%

The lower effective tax rate in 2017 when compared to 2016 is primarily due to a decrease to tax expense associated with the remeasurement of our net U.S. deferred tax liability as a result of enactment of the Tax Cuts and Jobs Act. The decrease in the effective tax rate in 2017 is also due to the recognition of excess tax benefits associated with the vesting of employee share-based compensation arrangements. See “Recent Accounting Pronouncements” of Note 2, “Summary of Significant Accounting Policies” for further discussion. The lower effective tax rate in 2016 when compared to 2015 is primarily due to a shift in the geographic mix of earnings, largely driven by the write-off of the eSpeed trade name, partially offset by an unfavorable ruling from the Finnish Supreme Administrative Court.

The effective tax rate may vary from period to period depending on, among other factors, the geographic and business mix of earnings and losses. These same and other factors, including the history of pre-tax earnings and losses, are taken into account in assessing the ability to realize deferred tax assets.

The temporary differences, which give rise to our deferred tax assets and (liabilities), consisted of the following:



	December 31,
	2017			2016
	(in millions)
Deferred tax assets:
Deferred revenues	$	25		$	39
U.S. federal net operating loss	1			2
Foreign net operating loss	30			37
State net operating loss	4			1
Compensation and benefits	42			99
Foreign currency translation	292			528
Tax credits	7			7
Other	20			34
Gross deferred tax assets	$	421		$	747

Deferred tax liabilities:
Amortization of software development costs and depreciation	$	(47	)	$	(63	)
Amortization of acquired intangible assets	(510		)	(596		)
Investments	(26		)	(37		)
Other	(19		)	(24		)
Gross deferred tax liabilities	(602		)	(720		)
Net deferred tax assets before valuation allowance	(181		)	27
Less: valuation allowance	(30		)	(30		)
Net deferred tax assets (liabilities)	$	(211	)	$	(3	)

A valuation allowance has been established with regards to the tax benefits primarily associated with certain net operating losses, or NOLs, as it is more likely than not that these benefits will not be realized in the foreseeable future.

As of December 31, 2017, the expiration dates for the NOLs, and credits are as follows:



Jurisdiction	Amount		Expiration Date
	(in millions)
U.S. Federal NOL	$	1	2033-2035
Foreign NOL	4		2018-2026
Foreign NOL	26		No expiration date
State NOL	4		2025-2036
U.S. Federal Tax credits	7		2018-2027

The following represents the domestic and foreign components of income before income tax provision:



	Year Ended December 31,
	2017		2016			2015
	(in millions)
Domestic	$	556	$	(155	)	$	393
Foreign	324		291			237
Income before income tax provision	$	880	$	136		$	630

We recorded income tax benefits of $40 million in 2017, $41 million in 2016 and $34 million in 2015, primarily related to share-based compensation. In 2017, the benefit was included in income tax expense. In 2016 and 2015, the amounts were recorded as additional paid-in-capital in the Consolidated Balance Sheets. See “Recent Accounting Pronouncements,” of Note 2, “Summary of Significant Accounting Policies,” for further discussion.

We are subject to examination by federal, state and local, and foreign tax authorities. We regularly assess the likelihood of additional assessments by each jurisdiction and have established tax reserves that we believe are adequate in relation to the potential for additional assessments. We believe that the resolution of tax matters will not have a material effect on our financial condition but may be material to our operating results for a particular period and the effective tax rate for that period.

There are $45 million as of December 31, 2017 and $48 million as of December 31, 2016 of unrecognized tax benefits that if recognized would affect our effective tax rate.

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:



	Year Ended December 31,
	2017			2016
	(in millions)
Beginning balance	$	48		$	40
Additions as a result of tax positions taken in prior periods	2			9
Additions as a result of tax positions taken in the current period	5			3
Reductions related to settlements with taxing authorities	—			(4		)
Reductions as a result of lapses of the applicable statute of limitations	(10		)	—
Ending balance	$	45		$	48

Our policy is to recognize interest and/or penalties related to income tax matters in income tax expense. We have accrued $9 million as of December 31, 2017 and $8 million as of December 31, 2016 for interest and penalties, net of tax effect.

Nasdaq and its eligible subsidiaries file a consolidated U.S. federal income tax return and applicable state and local income tax returns and non-U.S. income tax returns. Federal income tax returns for the years 2012 through 2015 are currently under examination by the Internal Revenue Services and we are subject to examination by the Internal Revenue Service for 2016. Several state tax returns are currently under examination by the respective tax authorities for the years 2005 through 2015 and we are subject to examination for 2016. Non-U.S. tax returns are subject to examination by the respective tax authorities for the years 2009 through 2016. Although the results of such examinations may have an impact on our unrecognized tax benefits, we do not anticipate that such impact will be material to our consolidated financial position or results of operations. Based on the expiration of the statute of limitations in the third quarter of 2017, we recognized $8 million in previously unrecognized tax benefits associated with positions taken in prior years. In addition, we anticipate that the amount of unrecognized tax benefits as of December 31, 2017 will decrease in the next twelve months as we expect to settle certain tax audits.

The Swedish Tax Agency has disallowed certain interest expense deductions for the years 2013 - 2015. We have appealed to the Lower Administrative Court. Despite a prior negative decision from the Council for Advance Rulings and the Supreme Administrative Court's refusal to hear our appeal at that time, we continue to expect a favorable decision from the Swedish Courts. Since January 1, 2013, we have recorded tax benefits of $56 million associated with this matter. We continue to pay all assessments from the Swedish Tax Agency while this matter is pending. If the Swedish Courts agree with our position we will receive a refund of all paid assessments; if the Swedish Courts disagree with our position, we will record tax expense of $48 million or $0.28 per diluted share, which is gross of any related U.S. tax benefits and reflects the impact of foreign currency translation. We record quarterly tax benefits of $1 million to $2 million related to this matter.

The Tax Cuts and Jobs Act was enacted on December 22, 2017 and is effective January 1, 2018. The new legislation contains several key provisions, including a reduction of the U.S. corporate income tax rate from 35% to 21%. We are required to remeasure all our U.S. deferred tax assets and liabilities as of December 22, 2017 and record the impact of such remeasurement in our 2017 financial statements. For the year ended December 31, 2017, we recorded a decrease to tax expense of $87 million, substantially all of which reflects the estimated impact associated with the remeasurement of our net U.S. deferred tax liability at the lower U.S. federal corporate income tax rate. The Tax Cuts and Jobs Act also imposes a transition tax on unremitted aggregate accumulated earnings of non-U.S. subsidiaries, which did not impact us.

SAB 118 has provided guidance which allows us to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. As of December 31, 2017, we have recorded a provisional estimate of the effects of the new legislation. We will continue to analyze the Tax Cuts and Jobs Act and related accounting guidance and interpretations in order to finalize any impacts within the measurement period.

Retirement Plans

12 Months Ended

Dec. 31, 2017

Retirement Benefits [Abstract]

Retirement Plans

Defined Contribution Savings Plan

We sponsor a 401(k) Plan for U.S. employees. Employees are immediately eligible to make contributions to the plan and are also eligible for an employer contribution match at an amount equal to 100.0% of the first 6.0% of eligible employee contributions. Savings plan expense included in compensation and benefits expense in the Consolidated Statements of Income was $13 million for 2017, $11 million for 2016 and $10 million for 2015.

Pension and Supplemental Executive Retirement Plans

We maintain non-contributory, defined-benefit pension plans, non-qualified SERPs for certain senior executives and other post-retirement benefit plans for eligible employees in the U.S., collectively referred to as the Nasdaq Benefit Plans. Our pension plans and SERPs are frozen. Future service and salary for all participants do not count toward an accrual of benefits under the pension plans and SERPs. Most employees outside the U.S. are covered by local retirement plans or by applicable social laws. Benefits under social laws are generally expensed in the periods in which the costs are incurred. The total expense for these plans is included in compensation and benefits expense in the Consolidated Statements of Income and was $21 million in 2017, $23 million in 2016 and $22 million in 2015.

Nasdaq recognizes the funded status of the Nasdaq Benefit Plans, measured as the difference between the fair value of the plan assets and the benefit obligation, in the Consolidated Balance Sheets. The funded status related to the Nasdaq Benefit Plans was underfunded by $60 million as of December 31, 2017, $59 million as of December 31, 2016 and $64 million as of December 31, 2015 and is included in accrued personnel costs and other non-current liabilities in the Consolidated Balance Sheets. The fair value of the plan assets was $79 million as of December 31, 2017 and $74 million as of December 31, 2016 and the benefit obligation was $139 million as of December 31, 2017 and $133 million as of December 31, 2016. The plan assets of the Nasdaq Benefit Plans are invested in securities per target allocations adopted by Nasdaq’s Pension and 401(k) Committee and are primarily invested in equity and fixed income securities, which are primarily categorized as Level 2 in the fair value hierarchy.

Accumulated Other Comprehensive Loss

As of December 31, 2017, accumulated other comprehensive loss for the Nasdaq Benefit Plans was $22 million reflecting an unrecognized net loss of $37 million, partially offset by an income tax benefit of $15 million, primarily due to our pension plans.

Estimated Future Benefit Payments

We expect to make the following benefit payments to participants in the next ten fiscal years under the Nasdaq Benefit Plans:



	Pension		SERP		Post-retirement		Total
Fiscal Year Ended:	(in millions)
2018	$	5	$	2	$	—	$	7
2019	5		7		—		12
2020	5		2		—		7
2021	5		2		—		7
2022	6		2		—		8
2023 through 2027	29		10		1		40
	$	55	$	25	$	1	$	81

Share-Based Compensation

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Share-Based Compensation

We have a share-based compensation program that provides our board of directors broad discretion in creating employee equity incentives. Share-based awards granted under this program include stock options, restricted stock (consisting of restricted stock units), and PSUs. For accounting purposes, we consider PSUs to be a form of restricted stock.

Summary of Share-Based Compensation Expense

The following table shows the total share-based compensation expense resulting from equity awards and the 15.0% discount for the ESPP for the years ended December 31, 2017, 2016 and 2015 in the Consolidated Statements of Income:



	Year Ended December 31,
	2017			2016			2015
	(in millions)
Share-based compensation expense before income taxes	$	70		$	86		$	68
Income tax benefit	(29		)	(35		)	(28		)
Share-based compensation expense after income taxes	$	41		$	51		$	40

Common Shares Available Under Our Equity Plan

As of December 31, 2017, we had approximately 5.8 million shares of common stock authorized for future issuance under our Equity Plan.

Restricted Stock

We grant restricted stock to most active employees. The grant date fair value of restricted stock awards is based on the closing price at the date of grant less the present value of future cash dividends. Restricted stock awards granted generally vest 25.0% on the second anniversary of the grant date, 25.0% on the third anniversary of the grant date, and 50.0% on the fourth anniversary of the grant date. We generally recognize compensation expense for restricted stock awards on a straight-line basis over the requisite service period of the award, taking into account an estimated forfeiture rate.

Summary of Restricted Stock Activity

The following table summarizes our restricted stock activity for the years ended December 31, 2017, 2016 and 2015:



	Restricted Stock
	Number of Awards		Weighted-Average Grant Date Fair Value
Unvested balances at December 31, 2014	3,193,230		$	30.99
Granted	823,950		$	49.26
Vested	(370,998	)	$	29.90
Forfeited	(302,444	)	$	34.34
Unvested balances at December 31, 2015	3,343,738		$	35.36
Granted	724,200		$	62.91
Vested	(1,238,980	)	$	27.91
Forfeited	(268,380	)	$	43.29
Unvested balances at December 31, 2016	2,560,578		$	45.92
Granted	737,864		$	67.48
Vested	(1,102,823	)	$	38.56
Forfeited	(207,119	)	$	52.29
Unvested balances at December 31, 2017	1,988,500		$	57.34

As of December 31, 2017, $54 million of total unrecognized compensation cost related to restricted stock is expected to be recognized over a weighted-average period of 1.8 years.

PSUs

The grant date fair value of PSUs is based on the closing price at the date of grant less the present value of future cash dividends. PSUs are based on performance measures that impact the amount of shares that each recipient will receive upon vesting. We report the target number of PSUs granted, unless we have determined that it is more likely than not, based on the actual achievement of performance measures, that an employee will receive a different amount of shares underlying the PSUs, in which case we report the amount of shares the employee is likely to receive. We have two performance-based long-term PSU programs for certain officers, a one-year performance-based program and a three-year cumulative performance-based program that focuses on TSR.

One-Year PSU Program

Under the one-year performance-based program, an employee may receive from 0.0% to 150.0% of the target amount granted, depending on the achievement of performance measures. These awards vest ratably on an annual basis over a three-year period commencing with the end of the performance period. Compensation cost is recognized over the performance period and the three-year vesting period, taking into account an estimated forfeiture rate.

During 2017, certain grants of PSUs with a one-year performance period exceeded the applicable performance parameters. As a result, an additional 14,497 units above target were considered granted in the first quarter of 2018.

Three-Year PSU Program

Under the three-year performance-based program, each individual receives PSUs with a three-year cumulative performance period that vest at the end of the performance period. Compensation cost is recognized over the three-year vesting period. Performance will be determined by comparing Nasdaq’s TSR to two peer groups, each weighted 50.0%. The first peer group consists of exchange companies, and the second peer group consists of all companies in the S&P 500. Nasdaq’s relative performance ranking against each of these groups will determine the final number of shares delivered to each individual under the program. The payout under this program will be between 0.0% and 200.0% of the number of PSUs granted and will be determined by Nasdaq’s overall performance against both peer groups. However, if Nasdaq’s TSR is negative for the three-year performance period, regardless of TSR ranking, the payout will not exceed 100.0% of the number of PSUs granted. We estimate the fair value of PSUs granted under the three-year PSU program using the Monte Carlo simulation model, as these awards contain a market condition.

Certain grants of PSUs that were issued in 2015 with a three-year performance period exceeded the applicable performance parameters. As a result, an additional 237,876 units above target were considered granted in the first quarter of 2018.

The following weighted-average assumptions were used to determine the weighted-average fair values of the PSU awards granted under the three-year PSU program for the years ended December 31, 2017 and 2016:



	Year Ended December 31,
	2017		2016
Weighted-average risk free interest rate⁽¹⁾	1.44	%	0.84	%
Expected volatility⁽²⁾	19.2	%	21.0	%
Weighted-average grant date share price	$69.45		$66.36
Weighted-average fair value at grant date	$81.57		$93.25

____________


⁽¹⁾	The risk-free interest rate for periods within the expected life of the award is based on the U.S. Treasury yield curve in effect at the time of grant.


⁽²⁾	We use historic volatility for PSU awards issued under the three-year PSU program, as implied volatility data could not be obtained for all the companies in the peer groups used for relative performance measurement within the program.

In addition, the annual dividend assumption utilized in the Monte Carlo simulation model is based on Nasdaq’s dividend yield at the date of grant.

Summary of PSU Activity

The following table summarizes our PSU activity for the years ended December 31, 2017, 2016 and 2015:



	PSUs
	One-Year Program				Three-Year Program
	Number of Awards		Weighted-Average Grant Date Fair Value		Number of Awards		Weighted-Average Grant Date Fair Value
Unvested balances at December 31, 2014	558,040		$	24.17	1,654,567		$	35.57
Granted	206,199		$	48.16	649,626		$	49.69
Vested	(247,273	)	$	30.51	(837,109	)	$	22.50
Forfeited	(92,999	)	$	34.74	(27,366	)	$	43.49
Unvested balances at December 31, 2015	423,967		$	41.34	1,439,718		$	49.41
Granted	242,642		$	58.33	761,501		$	66.89
Vested	(242,793	)	$	39.63	(879,926	)	$	43.81
Forfeited	(45,050	)	$	47.72	(6,625	)	$	69.11
Unvested balances at December 31, 2016	378,766		$	52.55	1,314,668		$	63.18
Granted	197,075		$	65.51	803,712		$	55.57
Vested	(202,073	)	$	49.93	(1,079,925	)	$	42.83
Forfeited	(40,764	)	$	55.92	(28,497	)	$	87.86
Unvested balances at December 31, 2017	333,004		$	61.39	1,009,958		$	78.18

As of December 31, 2017, $9 million of total unrecognized compensation cost related to the one-year PSU program is expected to be recognized over a weighted-average period of 1.4 years. For the three-year PSU program, $21 million of total unrecognized compensation cost is expected to be recognized over a weighted-average period of 1.4 years.

Stock Options

The fair value of stock options is estimated using the Black-Scholes option-pricing model. Each grant has a 10-year life. In January 2017, our CEO received 268,817 performance-based non-qualified stock options which will vest annually over a three-year period, with each vesting contingent upon the achievement of annual performance parameters. On January 30, 2018, Nasdaq's management compensation committee and board of directors determined that the performance goal for 2017 was met, resulting in the settlement of the first one-third of the grant. There were no stock option awards granted during the years ended December 31, 2016 and 2015.

Summary of Stock Option Activity

A summary of stock option activity for the year ended December 31, 2017 is as follows:



	Number of Stock Options		Weighted-Average Exercise Price

Outstanding at December 31, 2014	3,316,782		$	27.56
Exercised	(682,054	)	26.84
Forfeited	(8,241	)	28.53
Outstanding at December 31, 2015	2,626,487		$	27.74
Exercised	(1,219,820	)	34.00
Forfeited	(296	)	23.31
Outstanding at December 31, 2016	1,406,371		$	22.32
Granted	268,817		66.68
Exercised	(1,102,830	)	21.98
Forfeited	(978	)	21.33
Outstanding at December 31, 2017	571,380		$	43.84
Exercisable at December 31, 2017	302,563		$	23.55

We received net cash proceeds of $24 million from the exercise of 1,102,830 stock options for the year ended December 31, 2017, received net cash proceeds of $41 million from the exercise of 1,219,820 stock options for the year ended December 31, 2016 and received net cash proceeds of $18 million from the exercise of 682,054 stock options for the year ended December 31, 2015.

The following table summarizes significant ranges of outstanding and exercisable stock options as of December 31, 2017:



			Outstanding						Exercisable
Range of Exercise Prices			Number of Stock Options	Weighted-Average Remaining Contractual Term (in years)	Weighted-Average Exercise Price		Aggregate Intrinsic Value (in millions)		Number Exercisable	Weighted-Average Remaining Contractual Term (in years)	Weighted-Average Exercise Price		Aggregate Intrinsic Value (in millions)
$17.36	-	$19.99	94,265	2.14	$	19.73	$	5	94,265	2.14	$	19.73	$	5
$20.00	-	$25.75	206,980	2.39	25.20		11		206,980	2.39	25.20		11
$25.76	-	$66.68	270,135	8.84	66.53		3		1,318	0.48	36.40		—
Total			571,380	5.40	$	43.84	$	19	302,563	2.30	$	23.55	$	16

The aggregate intrinsic value in the above table represents the total pre-tax intrinsic value (i.e., the difference between our closing stock price on December 29, 2017 of $76.83 and the exercise price, times the number of shares) based on stock options with an exercise price less than Nasdaq’s closing price of $76.83 as of December 29, 2017, which would have been received by the option holders had the option holders exercised their stock options on that date. This amount can change based on the fair market value of our common stock. The total number of in-the-money stock options exercisable as of December 31, 2017 was 0.3 million and the weighted-average exercise price was $23.55. As of December 31, 2016, 1.4 million outstanding stock options were exercisable and the weighted-average exercise price was $22.32.

The total pre-tax intrinsic value of stock options exercised was $54 million during 2017, $40 million during 2016 and $17 million during 2015.

ESPP

We have an ESPP under which approximately 2.1 million shares of our common stock have been reserved for future issuance as of December 31, 2017. Under our ESPP, employees may purchase shares having a value not exceeding 10.0% of their annual compensation, subject to applicable annual Internal Revenue Service limitations. We record compensation expense related to the 15.0% discount that is given to our employees. The following table summarizes employee activity and expense associated with the ESPP for the years ended December 31, 2017, 2016 and 2015.



	Year Ended December 31,
	2017		2016		2015
Number of shares purchased by employees	235,859		233,464		247,444
Weighted-average price of shares purchased	$	58.26	$	50.39	$	40.95
Compensation expense (in millions)	$	3	$	4	$	4

Nasdaq Stockholders’ Equity

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Nasdaq Stockholders' Equity

Nasdaq Stockholders’ Equity

Common Stock

As of December 31, 2017, 300,000,000 shares of our common stock were authorized, 172,373,432 shares were issued and 167,441,030 shares were outstanding. The holders of common stock are entitled to one vote per share, except that our certificate of incorporation limits the ability of any person to vote in excess of 5.0% of the then-outstanding shares of Nasdaq common stock.

Common Stock in Treasury, at Cost

We account for the purchase of treasury stock under the cost method with the shares of stock repurchased reflected as a reduction to Nasdaq stockholders’ equity and included in common stock in treasury, at cost in the Consolidated Balance Sheets. Shares repurchased under our share repurchase program are currently retired and canceled. When treasury shares are reissued, they are recorded at the average cost of the treasury shares acquired. We held 4,932,402 shares of common stock in treasury as of December 31, 2017 and 3,921,718 shares as of December 31, 2016, most of which are related to shares of our common stock repurchased for the settlement of employee tax withholding obligations arising from the vesting of restricted stock.

Share Repurchase Program

In the fourth quarter of 2014, our board of directors authorized the repurchase of up to $500 million of our outstanding common stock and in the first quarter of 2016, our board of directors authorized the repurchase of an additional $370 million of our outstanding common stock under our share repurchase program.

These purchases may be made from time to time at prevailing market prices in open market purchases, privately-negotiated transactions, block purchase techniques or otherwise, as determined by our management. The purchases are primarily funded from existing cash balances. The share repurchase program may be suspended, modified or discontinued at any time.

The following table summarizes our share repurchase activity:



	Year Ended December 31,
	2017		2016
Number of shares of common stock repurchased	2,843,519		1,547,778
Average price paid per share	$	71.56	$	64.42
Total purchase price (in millions)	$	203	$	100

As discussed above in “Common Stock in Treasury, at Cost,” shares repurchased under our share repurchase program are currently retired and cancelled. As of December 31, 2017, the remaining amount authorized for share repurchases under the program was $226 million. In January 2018, the board of directors authorized an additional $500 million for the share repurchase program bringing the total capacity to $726 million. See “Definitive Agreement to Sell our Public Relations Solutions and Digital Media Services Businesses,” of Note 21, “Subsequent Events,” for further discussion.

Other Repurchases of Common Stock

For the year ended December 31, 2017, we repurchased 1,008,882 shares of our common stock in settlement of employee tax withholding obligations arising from the vesting of restricted stock.

Preferred Stock

Our certificate of incorporation authorizes the issuance of 30,000,000 shares of preferred stock, par value $0.01 per share, issuable from time to time in one or more series. As of December 31, 2017 and December 31, 2016, no shares of preferred stock were issued or outstanding.

* * * * * *

Cash Dividends on Common Stock

During 2017, our board of directors declared the following cash dividends:



Declaration Date	Dividend Per Common Share		Record Date	Total Amount Paid		Payment Date
				(in millions)
January 30, 2017	$	0.32	March 17, 2017	$	53	March 31, 2017
April 25, 2017	0.38		June 16, 2017	63		June 30, 2017
July 25, 2017	0.38		September 15, 2017	64		September 29, 2017
October 24, 2017	0.38		December 15, 2017	63		December 29, 2017
				$	243

The total amount paid of $243 million was recorded in retained earnings in the Consolidated Balance Sheets as of December 31, 2017.

In April 2017, the board of directors declared a regular quarterly cash dividend of $0.38 per share on our outstanding common stock which reflected a 19.0% increase from our prior quarterly cash dividend of $0.32. In addition, in April 2017, our board of directors adopted a dividend policy with the intention to provide shareholders with regular and growing dividends over the long term as earnings and cash flow grow.

In January 2018, the board of directors declared a regular quarterly cash dividend of $0.38 per share on our outstanding common stock. The dividend is payable on March 30, 2018 to shareholders of record at the close of business on March 16, 2018. The estimated amount of this dividend is $64 million. Future declarations of quarterly dividends and the establishment of future record and payment dates are subject to approval by the board of directors.

Accumulated Other Comprehensive Loss

The following table outlines the components of accumulated other comprehensive loss:



	Foreign Currency Translation Adjustments			Employee Benefit Plan Adjustments			Accumulated Other Comprehensive Loss
	(in millions)
Gross balance, December 31, 2016	$	(1,481	)	$	(35	)	$	(1,516	)
Income taxes	523			14			537
Net balance, December 31, 2016	$	(958	)	$	(21	)	$	(979	)

Gross balance, December 31, 2017	$	(1,268	)	$	(37	)	$	(1,305	)
Income taxes	428			15			443
Net balance, December 31, 2017	$	(840	)	$	(22	)	$	(862	)

Foreign currency translation adjustments include cumulative gains (losses) on foreign currency translation adjustments from non-U.S. subsidiaries for which the functional currency is other than the U.S. dollar.

Employee benefit plan adjustments represent unrecognized net actuarial gains (losses) related to the Nasdaq Benefit Plans.

Earnings Per Share

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Earnings Per Share

The following table sets forth the computation of basic and diluted earnings per share:



	Year Ended December 31,
	2017		2016		2015
	(in millions, except share and per share amounts)
Numerator:
Net income attributable to common shareholders	$	734	$	108	$	428
Denominator:
Weighted-average common shares outstanding for basic earnings per share	166,364,299		165,182,290		167,285,450
Weighted-average effect of dilutive securities:
Employee equity awards	2,861,892		3,258,136		3,638,981
Contingent issuance of common stock	358,840		360,571		358,840
Weighted-average common shares outstanding for diluted earnings per share	169,585,031		168,800,997		171,283,271
Basic and diluted earnings per share:
Basic earnings per share	$	4.41	$	0.65	$	2.56
Diluted earnings per share	$	4.33	$	0.64	$	2.50

Stock options to purchase 571,380 shares of common stock and 3,331,462 shares of restricted stock and PSUs were outstanding as of December 31, 2017. For the year ended December 31, 2017, we included 302,563 of the outstanding stock options and 2,978,856 shares of restricted stock and PSUs in the computation of diluted earnings per share, on a weighted-average basis, as their inclusion was dilutive. The remaining stock options, shares of restricted stock and PSUs are antidilutive, and as such, they were properly excluded.

Stock options to purchase 1,406,371 shares of common stock and 4,254,012 shares of restricted stock and PSUs were outstanding as of December 31, 2016. For the year ended December 31, 2016, we included all of the outstanding stock options and 3,663,919 shares of restricted stock and PSUs in the computation of diluted earnings per share, on a weighted-average basis, as their inclusion was dilutive. The remaining shares of restricted stock and PSUs are antidilutive, and as such, they were properly excluded.

Stock options to purchase 2,626,487 shares of common stock and 5,207,423 shares of restricted stock and PSUs were outstanding as of December 31, 2015. For the year ended December 31, 2015, we included all of the outstanding stock options and 4,842,383 shares of restricted stock and PSUs in the computation of diluted earnings per share, on a weighted-average basis, as their inclusion was dilutive. The remaining shares of restricted stock and PSUs are antidilutive, and as such, they were properly excluded.

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments

The following table presents our financial assets that are measured at fair value on a recurring basis as of December 31, 2017 and December 31, 2016. We did not have any financial liabilities measured at fair value on a recurring basis as of December 31, 2017 and December 31, 2016.



	December 31, 2017
	Total		Level 1		Level 2		Level 3
	(in millions)
Financial investments, at fair value	$	235	$	135	$	100	$	—
Default fund and margin deposit investments	2,129		371		1,758		—
Total	$	2,364	$	506	$	1,858	$	—



	December 31, 2016
	Total		Level 1		Level 2		Level 3
	(in millions)
Financial investments, at fair value	$	245	$	151	$	94	$	—
Default fund and margin deposit investments	1,900		614		1,286		—
Total	$	2,145	$	765	$	1,380	$	—

Our Level 1 financial investments, at fair value were comprised of trading securities, mainly highly rated European government debt securities. Level 2 financial investments, at fair value were primarily comprised of trading securities, mainly European mortgage and corporate bonds, as of December 31, 2017 and were primarily comprised of available-for-sale investment securities in short-term commercial paper and trading securities, mainly European mortgage and corporate bonds, as of December 31, 2016. Of the Level 1 and Level 2 financial investments, at fair value, $160 million as of December 31, 2017 and $172 million as of December 31, 2016 are assets utilized to meet regulatory capital requirements, primarily for our clearing operations at Nasdaq Clearing.

Our default fund and margin deposit investments include cash contributions invested by Nasdaq Clearing, in accordance with its investment policy. Of the total balance of $3,988 million recorded in the Consolidated Balance Sheets as of December 31, 2017, $1,909 million of cash contributions have been invested in highly rated European and U.S. government debt securities or central bank certificates and $220 million in reverse repurchase agreements. The remainder of this balance is held in cash. Of the total balance of $3,301 million recorded in the Consolidated Balance Sheets as of December 31, 2016, $1,763 million of cash contributions have been invested in highly rated European and U.S. government debt securities and central bank certificates and $137 million of cash contributions have been invested in reverse repurchase agreements. The remainder of this balance is held in cash. See Note 17, “Clearing Operations,” for further discussion of default fund contributions and margin deposits.

There were no transfers between Level 1 and Level 2 of the fair value hierarchy as of December 31, 2017 and December 31, 2016.

Financial Instruments Not Measured at Fair Value on a Recurring Basis

Some of our financial instruments are not measured at fair value on a recurring basis but are recorded at amounts that approximate fair value due to their liquid or short-term nature. Such financial assets and financial liabilities include: cash and cash equivalents, restricted cash, receivables, net, certain other current assets, accounts payable and accrued expenses, Section 31 fees payable to SEC, accrued personnel costs, commercial paper and certain other current liabilities.

In addition, our investments in OCC and EuroCCP N.V. are accounted for under the equity method of accounting and our investments in Borsa Istanbul and LCH.Clearnet Group Limited are carried at cost. See “Equity Method Investments,” and “Cost Method Investments,” of Note 7, “Investments,” for further discussion.

We also consider our debt obligations to be financial instruments. The fair value of our debt obligations, utilizing discounted cash flow analyses for our floating rate debt and prevailing market rates for our fixed rate debt, was $4.4 billion as of December 31, 2017 and $3.8 billion as of December 31, 2016. The discounted cash flow analyses are based on borrowing rates currently available to us for debt with similar terms and maturities. The fair value of our commercial paper approximates the carrying value since the rates of interest on this short-term debt approximate market rates as of December 31, 2017. Our commercial paper and our fixed rate and floating rate debt are categorized as Level 2 in the fair value hierarchy.

For further discussion of our debt obligations, see Note 10, “Debt Obligations.”

Non-Financial Assets Measured at Fair Value on a Non-Recurring Basis

Our non-financial assets, which include goodwill, intangible assets, and other long-lived assets, are not required to be carried at fair value on a recurring basis. Fair value measures of non-financial assets are primarily used in the impairment analysis of these assets. Any resulting asset impairment would require that the non-financial asset be recorded at its fair value. Nasdaq uses Level 3 inputs to measure the fair value of the above assets on a non-recurring basis. As of December 31, 2017 and December 31, 2016, there were no non-financial assets measured at fair value on a non-recurring basis.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Clearing Operations

12 Months Ended

Dec. 31, 2017

Due to and from Broker-Dealers and Clearing Organizations [Abstract]

Clearing Operations

Nasdaq Clearing

Nasdaq Clearing is authorized and supervised under EMIR as a multi-asset clearinghouse by the SFSA and is authorized to conduct clearing operations in Norway by the Norwegian Ministry of Finance. The clearinghouse acts as the CCP for exchange and OTC trades in equity derivatives, fixed income derivatives, resale and repurchase contracts, power derivatives, emission allowance derivatives, freight and fuel oil derivatives, iron ore derivatives and seafood derivatives.

Through our clearing operations in the financial markets, which include the resale and repurchase market, the commodities markets, and the seafood market, Nasdaq Clearing is the legal counterparty for, and guarantees the fulfillment of, each contract cleared. These contracts are not used by Nasdaq Clearing for the purpose of trading on its own behalf. As the legal counterparty of each transaction, Nasdaq Clearing bears the counterparty risk between the purchaser and seller in the contract. In its guarantor role, Nasdaq Clearing has precisely equal and offsetting claims to and from clearing members on opposite sides of each contract, standing as the CCP on every contract cleared. In accordance with the rules and regulations of Nasdaq Clearing, clearing members’ open positions are aggregated to create a single portfolio for which default fund and margin collateral requirements are calculated. See “Default Fund Contributions and Margin Deposits” below for further discussion of Nasdaq Clearing’s default fund and margin requirements.

Nasdaq Clearing maintains four member sponsored default funds: one related to financial markets, one related to commodities markets, one related to the seafood market, and a mutualized fund. Under this structure, Nasdaq Clearing and its clearing members must contribute to the total regulatory capital related to the clearing operations of Nasdaq Clearing. This structure applies an initial separation of default fund contributions for the financial, commodities and seafood markets in order to create a buffer for each market’s counterparty risks. Simultaneously, a mutualized default fund provides capital efficiencies to Nasdaq Clearing’s members with regard to total regulatory capital required. See “Default Fund Contributions” below for further discussion of Nasdaq Clearing’s default fund. Power of assessment and a liability waterfall also have been implemented. See “Power of Assessment” and “Liability Waterfall” below for further discussion. These requirements ensure the alignment of risk between Nasdaq Clearing and its clearing members.

Default Fund Contributions and Margin Deposits

As of December 31, 2017, clearing member default fund contributions and margin deposits were as follows:



	December 31, 2017
	Cash Contributions		Non-Cash Contributions		Total Contributions
	(in millions)
Default fund contributions	$	360	$	130	$	490
Margin deposits	3,628		4,047		7,675
Total	$	3,988	$	4,177	$	8,165

In accordance with its investment policy, of the total cash contributions of $3,988 million, Nasdaq Clearing has invested $1,909 million in highly rated European and U.S. government debt securities or central bank certificates and $220 million in reverse repurchase agreements. The remainder of this balance is held in cash. Of the total default fund contributions of $490 million, Nasdaq Clearing can utilize $454 million as capital resources in the event of a counterparty default. The remaining balance of $36 million pertains to member posted surplus balances.

Default Fund Contributions

Contributions made to the default funds are proportional to the exposures of each clearing member. When a clearing member is active in more than one market, contributions must be made to all markets’ default funds in which the member is active. Clearing members’ eligible contributions may include cash and non-cash contributions. Cash contributions received are held in cash or invested by Nasdaq Clearing, in accordance with its investment policy, either in highly rated government debt securities, time deposits, central bank certificates or reverse repurchase agreements with highly rated government debt securities as collateral. Nasdaq Clearing maintains and manages all cash deposits related to margin collateral. All risks and rewards of collateral ownership, including interest, belong to Nasdaq Clearing. Clearing members’ cash contributions are included in default funds and margin deposits in the Consolidated Balance Sheets as both a current asset and a current liability. Non-cash contributions include highly rated government debt securities that must meet specific criteria approved by Nasdaq Clearing. Non-cash contributions are pledged assets that are not recorded in the Consolidated Balance Sheets as Nasdaq Clearing does not take legal ownership of these assets and the risks and rewards remain with the clearing members. These balances may fluctuate over time due to changes in the amount of deposits required and whether members choose to provide cash or non-cash contributions. Assets pledged are held at a nominee account in Nasdaq Clearing’s name for the benefit of the clearing members and are immediately accessible by Nasdaq Clearing in the event of a default. In addition to clearing members’ required contributions to the liability waterfall, Nasdaq Clearing is also required to contribute capital to the liability waterfall and overall regulatory capital as specified under its clearinghouse rules. As of December 31, 2017, Nasdaq Clearing committed capital totaling $114 million to the liability waterfall and overall regulatory capital, in the form of government debt securities, which are recorded as financial investments, at fair value in the Consolidated Balance Sheets. The combined regulatory capital of the clearing members and Nasdaq Clearing will serve to secure the obligations of a clearing member and may be used to cover losses sustained by a clearing member in the event of a default.

Margin Deposits

Nasdaq Clearing requires all clearing members to provide collateral, which may consist of cash and non-cash contributions, to guarantee performance on the clearing members’ open positions, or initial margin. In addition, clearing members must also provide collateral to cover the daily margin call if needed. See “Default Fund Contributions” above for further discussion of cash and non-cash contributions.

Similar to default fund contributions, Nasdaq Clearing maintains and manages all cash deposits related to margin collateral. All risks and rewards of collateral ownership, including interest, belong to Nasdaq Clearing. These cash deposits are recorded in default funds and margin deposits in the Consolidated Balance Sheets as both a current asset and current liability. Pledged margin collateral is not recorded in our Consolidated Balance Sheets as all risks and rewards of collateral ownership, including interest, belong to the counterparty. Assets pledged are held at a nominee account in Nasdaq Clearing’s name for the benefit of the clearing members and are immediately accessible by Nasdaq Clearing in the event of a default.

Nasdaq Clearing marks to market all outstanding contracts and requires payment from clearing members whose positions have lost value. The mark-to-market process helps identify any clearing members that may not be able to satisfy their financial obligations in a timely manner allowing Nasdaq Clearing the ability to mitigate the risk of a clearing member defaulting due to exceptionally large losses. In the event of a default, Nasdaq Clearing can access the defaulting member’s margin deposits to cover the defaulting member’s losses.

Regulatory Capital and Risk Management Calculations

Nasdaq Clearing manages risk through a comprehensive counterparty risk management framework, which is comprised of policies, procedures, standards and financial resources. The level of regulatory capital is determined in accordance with Nasdaq Clearing’s regulatory capital policy, as approved by the SFSA. Regulatory capital calculations are continuously updated through a proprietary capital-at-risk calculation model that establishes the appropriate level of capital.

As mentioned above, Nasdaq Clearing is the legal counterparty for each contract traded and thereby guarantees the fulfillment of each contract. Nasdaq Clearing accounts for this guarantee as a performance guarantee. We determine the fair value of the performance guarantee by considering daily settlement of contracts and other margining and default fund requirements, the risk management program, historical evidence of default payments, and the estimated probability of potential default payouts. The calculation is determined using proprietary risk management software that simulates gains and losses based on historical market prices, extreme but plausible market scenarios, volatility and other factors present at that point in time for those particular unsettled contracts. Based on this analysis, the estimated liability was nominal and no liability was recorded as of December 31, 2017.

The market value of derivative contracts outstanding prior to netting was as follows:



	December 31, 2017
	(in millions)
Commodity and seafood options, futures and forwards^(1)(2)(3)	$	524
Fixed-income options and futures⁽¹⁾⁽²⁾	729
Stock options and futures⁽¹⁾⁽²⁾	132
Index options and futures⁽¹⁾⁽²⁾	111
Total	$	1,496

____________


⁽¹⁾	We determined the fair value of our option contracts using standard valuation models that were based on market-based observable inputs including implied volatility, interest rates and the spot price of the underlying instrument.


⁽²⁾	We determined the fair value of our futures contracts based upon quoted market prices and average quoted market yields.


⁽³⁾	We determined the fair value of our forward contracts using standard valuation models that were based on market-based observable inputs including LIBOR rates and the spot price of the underlying instrument.

The total number of derivative contracts cleared through Nasdaq Clearing for the years ended December 31, 2017 and 2016 was as follows:



	December 31, 2017	December 31, 2016
Commodity and seafood options, futures and forwards⁽¹⁾	2,824,188	3,530,746
Fixed-income options and futures	20,376,383	14,639,065
Stock options and futures	26,023,816	28,496,143
Index options and futures	44,928,284	50,636,527
Total	94,152,671	97,302,481

____________


(1)	The total volume in cleared power related to commodity contracts was 1,199 Terawatt hours (TWh) for the year ended December 31, 2017 and 1,658 TWh for the year ended December 31, 2016.

The outstanding contract value of resale and repurchase agreements was $2.3 billion as of December 31, 2017 and $1.9 billion as of December 31, 2016. The total number of contracts cleared was 8,534,986 for the year ended December 31, 2017 and was 7,941,666 for the year ended December 31, 2016.

Power of Assessment

To further strengthen the contingent financial resources of the clearinghouse, Nasdaq Clearing has power of assessment that provides the ability to collect additional funds from its clearing members to cover a defaulting member’s remaining obligations up to the limits established under the terms of the clearinghouse rules. The power of assessment corresponds to 100.0% of the clearing member’s aggregate contribution to the financial, commodities and seafood markets’ default funds.

Liability Waterfall

The liability waterfall is the priority order in which the capital resources would be utilized in the event of a default where the defaulting clearing member’s collateral would not be sufficient to cover the cost to settle its portfolio. If a default occurs and the defaulting clearing member’s collateral, including cash deposits and pledged assets, is depleted, then capital is utilized in the following amount and order:


•	junior capital contributed by Nasdaq Clearing, which totaled $18 million as of December 31, 2017;


•	a loss sharing pool related only to the financial market that is contributed to by clearing members and only applies if the defaulting member’s portfolio includes interest rate swap products;


•	specific market default fund where the loss occurred (i.e., the financial, commodities, or seafood market), which includes capital contributions of the clearing members on a pro-rata basis;


•	senior capital contributed to each specific market by Nasdaq Clearing, calculated in accordance with clearinghouse rules, which totaled $24 million as of December 31, 2017; and


•	mutualized default fund, which includes capital contributions of the clearing members on a pro-rata basis.

If additional funds are needed after utilization of the mutualized default fund, then Nasdaq Clearing will utilize its power of assessment and additional capital contributions will be required by non-defaulting members up to the limits established under the terms of the clearinghouse rules.

Leases

12 Months Ended

Dec. 31, 2017

Leases [Abstract]

Leases

We lease some of our office space under non-cancelable operating leases with third parties and sublease office space to third parties. Some of our lease agreements contain renewal options and escalation clauses based on increases in property taxes and building operating costs.

As of December 31, 2017, future minimum lease payments under non-cancelable operating leases (net of sublease income) are as follows:



	Gross Lease Commitments		Sublease Income		Net Lease Commitments
	(in millions)
Year ending December 31:
2018	$	90	$	3	$	87
2019	76		3		73
2020	70		3		67
2021	57		3		54
2022	51		3		48
Thereafter	113		3		110
Total future minimum lease payments	$	457	$	18	$	439

Rent expense for operating leases (net of sublease income of $3 million in 2017, $4 million in 2016, and $5 million in 2015) was $83 million in 2017, $78 million in 2016, and $88 million in 2015.

Commitments, Contingencies and Guarantees	12 Months Ended
Commitments, Contingencies and Guarantees	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Guarantees	Commitments, Contingencies and Guarantees Guarantees Issued and Credit Facilities Available In addition to the default fund contributions and margin collateral pledged by clearing members discussed in Note 17, “Clearing Operations,” we have obtained financial guarantees and credit facilities which are guaranteed by us through counter indemnities, to provide further liquidity related to our clearing businesses. Financial guarantees issued to us totaled $14 million as of December 31, 2017 and $13 million as of December 31, 2016. As discussed in “Other Credit Facilities,” of Note 10, “Debt Obligations,” clearing-related credit facilities, which are available in multiple currencies, totaled $187 million as of December 31, 2017 and $170 million as of December 31, 2016, in available liquidity, none of which was utilized. Execution Access is an introducing broker which operates the trading platform for our Fixed Income business to trade in U.S. Treasury securities. Execution Access has a clearing arrangement with Cantor Fitzgerald. As of December 31, 2017, we have contributed $19 million of clearing deposits to Cantor Fitzgerald in connection with this clearing arrangement. These deposits are recorded in other current assets in our Consolidated Balance Sheets. This clearing agreement will end on July 31, 2018, and will be replaced by a clearing agreement with ICBC. Some of the trading activity in Execution Access is cleared by Cantor Fitzgerald (and similarly will be by ICBC after July 31, 2018) through the Fixed Income Clearing Corporation. Execution Access assumes the counterparty risk of clients that do not clear through the Fixed Income Clearing Corporation. Counterparty risk of clients exists for Execution Access between the trade date and the settlement date of the individual transactions, which is at least one business day (or more, if specified by the U.S. Treasury issuance calendar). All of Execution Access’ obligations under the clearing arrangement with Cantor Fitzgerald are guaranteed by Nasdaq. Counterparties that do not clear through the Fixed Income Clearing Corporation are subject to a credit due diligence process and may be required to post collateral, provide principal letters, or provide other forms of credit enhancement to Execution Access for the purpose of mitigating counterparty risk. Daily position trading limits are also enforced for such counterparties. We believe that the potential for us to be required to make payments under these arrangements is mitigated through the pledged collateral and our risk management policies. Accordingly, no contingent liability is recorded in the Consolidated Balance Sheets for these arrangements. However, no guarantee can be provided that these arrangements will at all times be sufficient. Lease Commitments We lease some of our office space under non-cancelable operating leases with third parties and sublease office space to third parties. Some of our lease agreements contain renewal options and escalation clauses based on increases in property taxes and building operating costs. In February 2018, we entered into a lease agreement as part of a plan to relocate our world headquarters. See “New World Headquarters,” of Note 21, “Subsequent Events,” for further discussion. Other Guarantees We have provided other guarantees of $3 million as of December 31, 2017 and December 31, 2016. These guarantees are primarily related to obligations for our rental and leasing contracts as well as performance guarantees on certain market technology contracts related to the delivery of software technology and support services. We have received financial guarantees from various financial institutions to support the above guarantees. Through our clearing operations in the financial markets, Nasdaq Clearing is the legal counterparty for, and guarantees the performance of, its clearing members. See Note 17, “Clearing Operations,” for further discussion of Nasdaq Clearing performance guarantees. We have provided a guarantee related to lease obligations for The Nasdaq Entrepreneurial Center, Inc. which is a not-for-profit organization designed to convene, connect and engage aspiring and current entrepreneurs. This entity is not included in the consolidated financial statements of Nasdaq. We believe that the potential for us to be required to make payments under these arrangements is unlikely. Accordingly, no contingent liability is recorded in the Consolidated Balance Sheets for the above guarantees. Non-Cash Contingent Consideration As part of the purchase price consideration of a prior acquisition, we have agreed to future annual issuances of 992,247 shares of Nasdaq common stock which approximated certain tax benefits associated with the transaction. Such contingent future issuances of Nasdaq common stock will be paid ratably through 2027 if Nasdaq’s total gross revenues equal or exceed $25 million in each such year. The contingent future issuances of Nasdaq common stock are subject to anti-dilution protections and acceleration upon certain events. Escrow Agreements In connection with prior acquisitions, we entered into escrow agreements to secure the payment of post-closing adjustments and to ensure other closing conditions. As of December 31, 2017, these escrow agreements provide for future payment of $18 million, of which $14 million is included in other current liabilities and $4 million is included in other non-current liabilities in the Consolidated Balance Sheets. Routing Brokerage Activities One of our broker-dealer subsidiaries, Nasdaq Execution Services, provides a guarantee to securities clearinghouses and exchanges under its standard membership agreements, which require members to guarantee the performance of other members. If a member becomes unable to satisfy its obligations to a clearinghouse or exchange, other members would be required to meet its shortfalls. To mitigate these performance risks, the exchanges and clearinghouses often require members to post collateral, as well as meet certain minimum financial standards. Nasdaq Execution Services’ maximum potential liability under these arrangements cannot be quantified. However, we believe that the potential for Nasdaq Execution Services to be required to make payments under these arrangements is unlikely. Accordingly, no contingent liability is recorded in the Consolidated Balance Sheets for these arrangements. Legal and Regulatory Matters As previously disclosed, we were named as a defendant in a putative class action, Rabin v. NASDAQ OMX PHLX LLC, et al., No. 15-551 (E.D. Pa.), filed in 2015 in the United States District Court for the Eastern District of Pennsylvania. On April 21, 2016, the court entered an order granting our motion to dismiss the complaint. The plaintiff appealed the dismissal to the Court of Appeals for the Third Circuit on May 18, 2016. On October 25, 2017, the Third Circuit issued a decision affirming the dismissal of the case, and on November 22, 2017, denied a petition for rehearing and rehearing en banc. We also are named as one of many defendants in City of Providence v. BATS Global Markets, Inc., et al., 14 Civ. 2811 (S.D.N.Y.), which was filed on April 18, 2014 in the United States District Court for the Southern District of New York. The district court appointed lead counsel, who filed an amended complaint on September 2, 2014. The amended complaint names as defendants seven national exchanges, as well as Barclays PLC, which operated a private alternative trading system. On behalf of a putative class of securities traders, the plaintiffs allege that the defendants engaged in a scheme to manipulate the markets through high-frequency trading; the amended complaint asserts claims against us under Section 10(b) of the Exchange Act and Rule 10b-5, as well as under Section 6(b) of the Exchange Act. The plaintiffs seek injunctive and monetary relief of an unspecified amount. We filed a motion to dismiss the amended complaint on November 3, 2014. In response, the plaintiffs filed a second amended complaint on November 24, 2014, which names the same defendants and alleges essentially the same violations. We then filed a motion to dismiss the second amended complaint on January 23, 2015. On August 26, 2015, the district court entered an order dismissing the second amended complaint in its entirety with prejudice, concluding that most of the plaintiffs’ theories were foreclosed by absolute immunity and in any event that the plaintiffs failed to state any claim. The plaintiffs appealed the judgment of dismissal to the United States Court of Appeals for the Second Circuit. The Second Circuit heard oral argument on August 24, 2016. On August 25, 2016, the Second Circuit issued an order requesting the SEC’s views on whether the district court had subject-matter jurisdiction over the case, and whether the defendants are immune from suit regarding the challenged conduct. The SEC filed its brief on November 28, 2016. The exchanges and plaintiffs filed supplemental briefs responding to the SEC’s brief on December 12, 2016. On December 19, 2017, the Second Circuit issued an opinion vacating the district court’s judgment of dismissal and remanding to the district court for further proceedings. The exchanges filed a petition before the Second Circuit seeking panel or en banc rehearing on January 31, 2018, addressing Section 10(b) and Rule 10b-5 issues and absolute immunity. Given the preliminary nature of the proceedings, we are unable to estimate what, if any, liability may result from this litigation. However, we believe (as the district court concluded) that the claims are without merit and will continue to litigate vigorously. Except as disclosed above and in prior reports filed under the Exchange Act, we are not currently a party to any litigation or proceeding that we believe could have a material adverse effect on our business, consolidated financial condition, or operating results. However, from time to time, we have been threatened with, or named as a defendant in, lawsuits or involved in regulatory proceedings. In the normal course of business, Nasdaq discusses matters with its regulators raised during regulatory examinations or otherwise subject to their inquiry and oversight. These matters could result in censures, fines, penalties or other sanctions. Management believes the outcome of any resulting actions will not have a material impact on its consolidated financial position or results of operations. However, we are unable to predict the outcome or the timing of the ultimate resolution of these matters, or the potential fines, penalties or injunctive or other equitable relief, if any, that may result from these matters. Tax Audits We are engaged in ongoing discussions and audits with taxing authorities on various tax matters, the resolutions of which are uncertain. Currently, there are matters that may lead to assessments, some of which may not be resolved for several years. Based on currently available information, we believe we have adequately provided for any assessments that could result from those proceedings where it is more likely than not that we will be assessed. We review our positions on these matters as they progress.

Business Segments

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Business Segments

We manage, operate and provide our products and services in four business segments: Market Services, Corporate Services, Information Services and Market Technology. See Note 1, “Organization and Nature of Operations,” for further discussion of our reportable segments.

Our management allocates resources, assesses performance and manages these businesses as four separate segments. We evaluate the performance of our segments based on several factors, of which the primary financial measure is operating income. Results of individual businesses are presented based on our management accounting practices and structure.

The following table presents certain information regarding our operating segments for the years ended December 31, 2017, 2016 and 2015 :



	Market Services			Corporate Services		Information Services		Market Technology		Corporate Items			Consolidated
	(in millions)
2017
Total revenues	$	2,418		$	656	$	588	$	303	$	—		$	3,965
Transaction-based expenses	(1,537		)	—		—		—		—			(1,537		)
Revenues less transaction-based expenses	881			656		588		303		—			2,428
Depreciation and amortization	95			49		25		$	19	—			188
Operating income (loss)	481			184		418		$	65	(149		)	999
Total assets	9,471			866		3,420		627		1,402			15,786
Purchase of property and equipment	59			41		10		34		—			144
2016
Total revenues	$	2,255		$	635	$	540	$	275	$	—		$	3,705
Transaction-based expenses	(1,428		)	—		—		—		—			(1,428		)
Revenues less transaction-based expenses	827			635		540		275		—			2,277
Depreciation and amortization	87			47		18		18		—			170
Operating income (loss)	450			158		383		69		(221		)	839
Total assets	8,626			1,263		2,439		559		1,263			14,150
Purchase of property and equipment	62			37		8		27		—			134
2015
Total revenues	$	2,084		$	562	$	512	$	245	$	—		$	3,403
Transaction-based expenses	(1,313		)	—		—		—		—			(1,313		)
Revenues less transaction-based expenses	771			562		512		245		—			2,090
Depreciation and amortization	64			42		14		18		—			138
Operating income (loss)	413			140		365		58		(256		)	720
Total assets	6,906			576		2,456		752		1,171			11,861
Purchase of property and equipment	53			38		11		31		—			133

Certain amounts are allocated to corporate items in our management reports based on the decision that those activities should not be used to evaluate the segment’s ongoing operating performance. The following items are allocated to corporate items for segment reporting purposes:

Amortization expense of acquired intangible assets: We amortize intangible assets acquired in connection with various acquisitions. Intangible asset amortization expense can vary from period to period due to episodic acquisitions completed, rather than from our ongoing business operations. As such, if intangible asset amortization is included in performance measures, it is more difficult to assess the day-to-day operating performance of the segments, and the relative operating performance of the segments between periods. Management does not consider intangible asset amortization expense for the purpose of evaluating the performance of our segments or their managers or when making decisions to allocate resources. Therefore, we believe performance measures excluding intangible asset amortization expense provide management with a more useful representation of our segments' ongoing activity in each period.

Merger and strategic initiatives expense: We have pursued various strategic initiatives and completed a number of acquisitions in recent years which have resulted in expenses which would not have otherwise been incurred. These expenses generally include integration costs, as well as legal, due diligence and other third party transaction costs. The frequency and the amount of such expenses vary significantly based on the size, timing and complexity of the transaction. Accordingly, we do not allocate these costs for purposes of disclosing segment results because they do not contribute to a meaningful evaluation of a particular segment’s ongoing operating performance.

Restructuring charges: Restructuring charges are associated with our 2015 restructuring plan to improve performance, cut costs and reduce spending and are primarily related to (i) severance and other termination benefits, (ii) asset impairment charges, and (iii) other charges. We do not allocate these restructuring costs because they do not contribute to a meaningful evaluation of a particular segment’s ongoing operating performance.

Other significant items: We have excluded certain other charges or gains that are the result of other non-comparable events to measure operating performance. For the year ended December 31, 2017, other significant items included loss on extinguishment of debt and a sublease loss reserve charge recorded on space we currently occupy due to excess capacity. For 2016, other significant items primarily included a regulatory fine received by our exchange in Stockholm and Nasdaq Clearing, the release of a sublease loss reserve due to the early exit of a facility and costs associated with the acceleration of previously granted equity awards due to the retirement of our former CEO. For 2015, other significant items included the reversal of a VAT refund. We believe the exclusion of such amounts allows management and investors to better understand the financial results of Nasdaq.

* * * * * *

A summary of our corporate items is as follows:



	Year Ended December 31,
	2017		2016			2015
	(in millions)
Amortization expense of acquired intangible assets	$	92	$	82		$	62
Merger and strategic initiatives expense	44		76			10
Restructuring charges	—		41			172
Loss on extinguishment of debt	10		—			—
Regulatory matter	1		6			—
Sublease loss reserve	2		(1		)	—
Reversal of VAT refund receivables	—		—			12
Executive compensation	—		12			—
Other	—		5			—
Total	$	149	$	221		$	256

Total assets increased $1,636 million as of December 31, 2017 compared with December 31, 2016 primarily due to an increase in default funds and margin deposits, reflecting an increase in cash margin deposits pledged by members of our Nasdaq Clearing business resulting from an increase in clearing volume. Also contributing to the increase is an increase in goodwill and intangible assets associated with our 2017 acquisitions, partially offset by a decrease in deferred tax assets primarily due to the impact of the Tax Cuts and Jobs Act. See Note 11, “Income Taxes,” for further discussion. Total assets increased $2,289 million as of December 31, 2016 compared with December 31, 2015 primarily due to new regulatory rules in 2016 that require all collateral pledged by members of our Nasdaq Clearing business to be recorded on the balance sheet and an increase in goodwill associated with our 2016 acquisitions, partially offset by a pre-tax, non-cash intangible asset impairment charge of $578 million to write off the full value of the eSpeed trade name. For further discussion of the impairment charge, see “Intangible Asset Impairment Charges,” of Note 6, “Goodwill and Acquired Intangible Assets.”

For further discussion of our segments’ results, see “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations—Segment Operating Results.”

Geographic Data

The following table presents total revenues and property and equipment, net by geographic area for 2017, 2016 and 2015. Revenues are classified based upon the location of the customer. Property and equipment information is based on the physical location of the assets.



	Total Revenues		Property and Equipment, Net
	(in millions)
2017:
United States	$	3,062	$	247
All other countries	903		153
Total	$	3,965	$	400

2016:
United States	$	2,659	$	244
All other countries	1,046		118
Total	$	3,705	$	362

2015:
United States	$	2,408	$	217
All other countries	995		106
Total	$	3,403	$	323

Our property and equipment, net for all other countries primarily includes assets held in Sweden.

No single customer accounted for 10.0% or more of our revenues in 2017, 2016 and 2015.

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2017
Subsequent Events [Abstract]
Subsequent Event	Subsequent Events Definitive Agreement to Sell our Public Relations Solutions and Digital Media Services Businesses In January 2018, we announced that we entered into a definitive agreement to sell our Public Relations Solutions and Digital Media Services businesses within our Corporate Solutions business for $335 million, subject to post-closing adjustments. The closing of this transaction, which is subject to regulatory approvals and customary closing conditions, is projected to occur in the second quarter of 2018. Nasdaq expects to use the proceeds from the sale for share repurchases. In conjunction with this, Nasdaq's board of directors has authorized an additional $500 million for the share repurchase program bringing the total capacity to $726 million. New World Headquarters In February 2018, we announced that we will consolidate our offices in New York City and move to a single location at MarketSite, 4 Times Square, New York, NY which will be our new world headquarters. As part of this plan, we entered into a new lease agreement for additional space at the MarketSite location.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Basis of Presentation

Basis of Presentation and Principles of Consolidation

Consolidation

Certain prior year amounts have been reclassified to conform to the current year presentation.

Use of Estimates

Foreign Currency

Cash and Cash Equivalents

Restricted Cash

Financial Investments

Receivables, net

Default Funds and Margin Deposits

Derivative Financial Instruments and Hedging Activities

Non-Designated Derivatives

As of December 31, 2017 and 2016, the fair value amounts of our derivative instruments were immaterial.

Net Investment Hedges

Property and Equipment, net

Leasehold improvements are amortized using the straight-line method over the shorter of their estimated useful lives or the remaining term of the related lease.

Goodwill and Indefinite-Lived Intangible Assets

The quantitative goodwill test consists of two steps:


•	The first step compares the fair value of each reporting unit with its carrying amount, including goodwill. If the reporting unit’s fair value exceeds its carrying amount, goodwill is not impaired.


•	If the fair value of a reporting unit is less than its carrying amount, the second step of the goodwill test is performed to measure the amount of impairment, if any. An impairment is equal to the excess of the carrying amount of goodwill over its fair value.

Valuation of Other Long-Lived Assets

Equity Method Investments

Cost Method Investments

Revenue Recognition and Transaction-Based Expenses

Market Services Revenues

Market services revenues include equity derivative trading and clearing revenues, cash equity trading revenues, FICC revenues, and trade management services revenues.

Equity Derivative Trading and Clearing and Cash Equity Trading Revenues

Equity Derivative Trading and Clearing Revenues

Cash Equity Trading Revenues

Equity Derivative Trading and Clearing and Cash Equity Trading Transaction-Based Expenses

FICC Revenues

Trade Management Services Revenues

Access Services

Broker Services

Corporate Services Revenues

Corporate services revenues include corporate solutions revenues and listing services revenues.

Corporate Solutions Revenues

Listing Services Revenues

Listing services revenues primarily include annual renewal fees, initial listing fees and listing of additional shares fees.

Annual Renewal Fees

Initial Listing Fees

Listing of Additional Shares Fees

All-Inclusive Annual Listing Fee Program

Information Services Revenues

Information services revenues include data products revenues and index licensing and services revenues.

Data Products Revenues

Data products revenues are earned from U.S. and European proprietary data products and index data products. In the U.S., we also earn revenues from U.S. tape plans.

Data Products Revenue Sharing


•	Primary Obligor: We are the administrator for the UTP Plan, in addition to being a participant in the UTP Plan. In our unique role as administrator, we facilitate the collection and dissemination of revenues on behalf of the UTP Plan participants. As a participant, we share in the net distribution of revenues according to the plan on the same terms as all other plan participants.


•	Risk of Loss/Credit Risk: Risk of loss on the revenue is shared equally among plan participants according to the UTP Plan.


•	Price Latitude: The operating committee of the UTP Plan, which is comprised of representatives from each of the participants, including us solely in our capacity as a UTP Plan participant, is responsible for setting the level of fees to be paid by distributors and subscribers and taking action in accordance with the provisions of the UTP Plan, subject to SEC approval.

The exchanges that comprise Nasdaq Nordic and Nasdaq Baltic do not have any data products revenue sharing agreements.

Index Licensing and Services Revenues

Market Technology Revenues

We enter into agreements to modify the system solutions sold by Nasdaq after delivery has occurred. These revenues are recognized when earned.

Revenue recognition for our Market Technology business was impacted due to the adoption of ASU 2014-09, “Revenue from Contracts with Customers.”

Earnings Per Share

Pension and Post-Retirement Benefits

Share-Based Compensation

We generally recognize compensation expense for equity awards on a straight-line basis over the requisite service period of the award, taking into account an estimated forfeiture rate.

Leases

Fair Value Measurements


•	Level 1—Quoted prices for identical instruments in active markets.


•	Level 2—Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable or whose significant value drivers are observable.


•	Level 3—Instruments whose significant value drivers are unobservable.

This hierarchy requires the use of observable market data when available.

Tax Matters

Recently Adopted and Issued Accounting Pronouncements

Recent Accounting Pronouncements



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Compensation - Stock Compensation In March 2016, the FASB issued ASU 2016-09, “Improvements to Employee Share-Based Payment Accounting.”	This ASU involves several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This guidance requires all income tax effects of awards to be recognized as income tax expense or benefit in the income statement when the awards vest or are settled, as opposed to additional paid-in-capital where it was previously recorded. This guidance impacts the calculation of our total diluted share count for the earnings per share calculation, as calculated under the treasury stock method. It also allows an employer to repurchase more of an employee’s shares for tax withholding purposes without triggering liability accounting. All tax-related cash flows resulting from share-based payments are reported as operating activities on the statement of cash flows. In regards to forfeitures, a policy election is required to either estimate the number of awards that are expected to vest or account for forfeitures as they occur.	We adopted this standard on January 1, 2017 on a prospective basis for the impacts on the accounting for income taxes and the effect on earnings per share. We adopted the changes for the cash flow statement classification retrospectively.	The adoption resulted in the recognition of excess tax benefits in our provision for income taxes rather than additional paid-in capital of $40 million for the year ended December 31, 2017.
Compensation - Stock Compensation In May 2017, the FASB issued ASU 2017-09, “Scope of Modification Accounting.”	This ASU clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) change as a result of the change in terms or conditions.	We adopted this standard on June 30, 2017 on a prospective basis.	Adopting this standard had no impact on our consolidated financial statements. The future impact will depend on the extent and nature of future changes to the terms of our share-based payment awards. Historically, we have not had significant changes to our share-based payment awards and therefore do not expect adoption of this guidance to have a material impact on our consolidated financial statements.
Business Combination In January 2017, the FASB issued ASU 2017-01, “Clarifying the Definition of a Business.”	This ASU clarifies the definition of a business with the objective of adding guidance to assist companies with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The new guidance is expected to reduce the number of transactions that need to be further evaluated as businesses. Early adoption is permitted for certain types of transactions.	We adopted this standard on January 1, 2018 on a prospective basis.	None. However, this standard may impact how we account for future acquisitions.



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Goodwill In January 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment.”	This ASU simplifies how an entity is required to test goodwill for impairment and removes the second step of the goodwill impairment test, which required a hypothetical purchase price allocation if the fair value of a reporting unit is less than its carrying amount. Goodwill impairment will now be measured using the difference between the carrying amount and the fair value of the reporting unit and the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The amendments in this ASU should be applied on a prospective basis. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017.	January 1, 2020, with early adoption as of January 1, 2017 permitted.	We do not anticipate a material impact on our consolidated financial statements at the time of adoption of this new standard as the carrying amounts of our reporting units have been less than their corresponding fair values in recent years. Therefore, the second step of the goodwill impairment test was not required. However, changes in future projections, market conditions and other factors may cause a change in the excess of fair value of our reporting units over their corresponding carrying amounts. We do not anticipate early adoption of this standard.
Financial Instruments - Credit Losses In June 2016, the FASB issued ASU 2016-13, “Measurement of Credit Losses on Financial Instruments.”	This ASU changes the impairment model for certain financial instruments. The new model is a forward looking expected loss model and will apply to financial assets subject to credit losses and measured at amortized cost and certain off-balance sheet credit exposures. This includes loans, held-to-maturity debt securities, loan commitments, financial guarantees and net investments in leases, as well as trade receivables. For available-for-sale debt securities with unrealized losses, credit losses will be measured in a manner similar to today, except that the losses will be recognized as allowances rather than reductions in the amortized cost of the securities.	January 1, 2020, with early adoption permitted as of January 1, 2019.	We are currently assessing the impact that this standard will have on our consolidated financial statements. We do not anticipate early adoption of this standard.



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Leases In February 2016, the FASB issued ASU 2016-02, “Leases.”	Under this ASU, at the commencement date, lessees will be required to recognize a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. This guidance is not applicable for leases with a term of 12 months or less. Lessor accounting is largely unchanged.	January 1, 2019, with early adoption permitted.	When adopted, ASU 2016-02 will result in an increase in the assets and liabilities reflected on our consolidated balance sheets. In addition, we will be required to disclose key information about our leases. We are currently assessing the significance that this standard will have on our consolidated financial statements. We do not anticipate early adoption of this standard.
Financial Instruments - Overall In January 2016, the FASB issued ASU 2016-01, “Recognition and Measurement of Financial Assets and Financial Liabilities.”	This ASU requires that most equity investments be measured at fair value, with subsequent changes in fair value recognized in net income. Under this new guidance, Nasdaq will no longer be able to recognize unrealized holding gains and losses on equity securities classified today as available-for-sale in accumulated other comprehensive income within stockholders’ equity. For certain equity investments that do not have readily determinable fair values, there is a new measurement alternative where those investments are measured at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. This new standard does not change the guidance for classifying and measuring investments in debt securities and loans. This new guidance also impacts financial liabilities accounted for under the fair value option and affects the presentation and disclosure requirements for financial assets and liabilities.	We adopted this standard on January 1, 2018 on a prospective basis.	Since we do not have a significant investment in financial instruments impacted by this standard at the time of adoption, there was no material impact on our consolidated financial statements. We have elected the measurement alternative for equity investments which were historically accounted for under the cost method of accounting. This could result in volatility in earnings.



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Income Statement - Reporting Comprehensive Income In February 2018, the FASB issued ASU 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.”	This ASU provides an election to reclassify tax effects that are stranded in accumulated other comprehensive income as a result of tax reform to retained earnings. An election is also available to reclassify other stranded tax effects that relate to the Tax Cuts and Jobs Act but do not directly relate to the change in the federal rate. Tax effects that are stranded in accumulated other comprehensive income for other reasons (e.g., prior changes in tax law, a change in valuation allowance) may not be reclassified. Previously, the effects of changes in tax rates and laws on deferred tax balances were required to be recorded as a component of tax expense related to continuing operations for the period in which the law was enacted, even if the assets and liabilities related to items of accumulated other comprehensive income. In other words, backward tracing of the income tax effects of items originally recognized through accumulated other comprehensive income was prohibited.	January 1, 2019, with early adoption permitted.	We are currently assessing the impact that this standard will have on our consolidated financial statements.
Revenue From Contracts With Customers In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes the revenue recognition guidance in Accounting Standards Codification, “Revenue Recognition.”	The new revenue recognition standard sets forth a five-step revenue recognition model to determine when and how revenue is recognized. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration it expects to receive in exchange for those goods or services. The standard also requires more detailed disclosures. The standard provides alternative methods of initial adoption.	We adopted this standard on January 1, 2018 using the full retrospective method.	See discussion below.

Revenue From Contracts With Customers

The following are key items to note regarding the accounting for our Market Technology and Listing Services businesses under Topic 606:


•	revenue recognition for existing and new contracts is recognized in earlier stages under the new standard;


•	expense recognition for Market Technology contracts is recognized in earlier stages under the new standard;


•	a portion of revenues and expenses that were previously deferred were recognized either in prior period revenues, through restatement, or as an adjustment to retained earnings upon adoption of the new standard; and


•	the overall value of our contracts and the timing of cash flows from customers did not change.

The following tables present the expected effect of the adoption of Topic 606 on our Consolidated Statements of Income for the years ended December 31, 2017 and 2016:



	Year Ended December 31, 2017							Year Ended December 31, 2016
	As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted		As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted
	(in millions)							(in millions)
Revenues less transaction-based expenses:
Market Services	$	881	$	—		$	881	$	827	$	—		$	827
Corporate Services	656		(3		)	653		635		(3		)	632
Information Services	588		—			588		540		—			540
Market Technology	303		(14		)	289		275		2			277
Total revenues less transaction-based expenses	2,428		(17		)	2,411		2,277		(1		)	2,276

Total operating expenses ⁽¹⁾	1,429		(9		)	1,420		1,438		2			1,440

Income before income taxes	880		(8		)	872		136		(3		)	133
Income tax provision (benefit)	146		(3		)	143		28		(1		)	27
Net income attributable to Nasdaq	$	734	$	(5	)	$	729	$	108	$	(2	)	$	106
Diluted earnings per share	$	4.33	$	(0.03	)	$	4.30	$	0.64	$	(0.01	)	$	0.63

____________

⁽¹⁾ Adjustment to reflect the adoption of Topic 606 for the year ended December 31, 2017 and 2016 primarily pertains to our Market Technology business.



	December 31, 2017							December 31, 2016
	As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted		As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted
	(in millions)							(in millions)
Assets:
Other current assets	$	187	$	(19	)	$	168	$	167	$	(15	)	$	152
Other non-current assets	412		(38		)	374		390		(46		)	344
Deferred tax assets	391		2			393		717		(1		)	716
Total assets	$	15,786	$	(55	)	$	15,731	$	14,150	$	(62	)	$	14,088

Liabilities:
Deferred revenue	$	189	$	(28	)	$	161	$	162	$	(24	)	$	138
Non-current deferred revenue	146		(20		)	126		171		(36		)	135
Total liabilities	$	9,899	$	(48	)	$	9,851	$	8,720	$	(60	)	$	8,660

Nasdaq stockholders' equity:
Retained earnings	$	3,970	$	(7	)	$	3,963	$	3,479	$	(2	)	$	3,477
Total Nasdaq stockholders' equity	5,887		(7		)	5,880		5,430		(2		)	5,428
Total liabilities and equity	$	15,786	$	(55	)	$	15,731	$	14,150	$	(62	)	$	14,088

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Accounting Policies [Abstract]

Schedule of the Recent Accounting Pronouncements

Recent Accounting Pronouncements



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Compensation - Stock Compensation In March 2016, the FASB issued ASU 2016-09, “Improvements to Employee Share-Based Payment Accounting.”	This ASU involves several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This guidance requires all income tax effects of awards to be recognized as income tax expense or benefit in the income statement when the awards vest or are settled, as opposed to additional paid-in-capital where it was previously recorded. This guidance impacts the calculation of our total diluted share count for the earnings per share calculation, as calculated under the treasury stock method. It also allows an employer to repurchase more of an employee’s shares for tax withholding purposes without triggering liability accounting. All tax-related cash flows resulting from share-based payments are reported as operating activities on the statement of cash flows. In regards to forfeitures, a policy election is required to either estimate the number of awards that are expected to vest or account for forfeitures as they occur.	We adopted this standard on January 1, 2017 on a prospective basis for the impacts on the accounting for income taxes and the effect on earnings per share. We adopted the changes for the cash flow statement classification retrospectively.	The adoption resulted in the recognition of excess tax benefits in our provision for income taxes rather than additional paid-in capital of $40 million for the year ended December 31, 2017.
Compensation - Stock Compensation In May 2017, the FASB issued ASU 2017-09, “Scope of Modification Accounting.”	This ASU clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as modifications. Under the new guidance, modification accounting is required only if the fair value, the vesting conditions, or the classification of the award (as equity or liability) change as a result of the change in terms or conditions.	We adopted this standard on June 30, 2017 on a prospective basis.	Adopting this standard had no impact on our consolidated financial statements. The future impact will depend on the extent and nature of future changes to the terms of our share-based payment awards. Historically, we have not had significant changes to our share-based payment awards and therefore do not expect adoption of this guidance to have a material impact on our consolidated financial statements.
Business Combination In January 2017, the FASB issued ASU 2017-01, “Clarifying the Definition of a Business.”	This ASU clarifies the definition of a business with the objective of adding guidance to assist companies with evaluating whether transactions should be accounted for as acquisitions (or disposals) of assets or businesses. The new guidance is expected to reduce the number of transactions that need to be further evaluated as businesses. Early adoption is permitted for certain types of transactions.	We adopted this standard on January 1, 2018 on a prospective basis.	None. However, this standard may impact how we account for future acquisitions.



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Goodwill In January 2017, the FASB issued ASU 2017-04, “Simplifying the Test for Goodwill Impairment.”	This ASU simplifies how an entity is required to test goodwill for impairment and removes the second step of the goodwill impairment test, which required a hypothetical purchase price allocation if the fair value of a reporting unit is less than its carrying amount. Goodwill impairment will now be measured using the difference between the carrying amount and the fair value of the reporting unit and the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The amendments in this ASU should be applied on a prospective basis. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017.	January 1, 2020, with early adoption as of January 1, 2017 permitted.	We do not anticipate a material impact on our consolidated financial statements at the time of adoption of this new standard as the carrying amounts of our reporting units have been less than their corresponding fair values in recent years. Therefore, the second step of the goodwill impairment test was not required. However, changes in future projections, market conditions and other factors may cause a change in the excess of fair value of our reporting units over their corresponding carrying amounts. We do not anticipate early adoption of this standard.
Financial Instruments - Credit Losses In June 2016, the FASB issued ASU 2016-13, “Measurement of Credit Losses on Financial Instruments.”	This ASU changes the impairment model for certain financial instruments. The new model is a forward looking expected loss model and will apply to financial assets subject to credit losses and measured at amortized cost and certain off-balance sheet credit exposures. This includes loans, held-to-maturity debt securities, loan commitments, financial guarantees and net investments in leases, as well as trade receivables. For available-for-sale debt securities with unrealized losses, credit losses will be measured in a manner similar to today, except that the losses will be recognized as allowances rather than reductions in the amortized cost of the securities.	January 1, 2020, with early adoption permitted as of January 1, 2019.	We are currently assessing the impact that this standard will have on our consolidated financial statements. We do not anticipate early adoption of this standard.



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Leases In February 2016, the FASB issued ASU 2016-02, “Leases.”	Under this ASU, at the commencement date, lessees will be required to recognize a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. This guidance is not applicable for leases with a term of 12 months or less. Lessor accounting is largely unchanged.	January 1, 2019, with early adoption permitted.	When adopted, ASU 2016-02 will result in an increase in the assets and liabilities reflected on our consolidated balance sheets. In addition, we will be required to disclose key information about our leases. We are currently assessing the significance that this standard will have on our consolidated financial statements. We do not anticipate early adoption of this standard.
Financial Instruments - Overall In January 2016, the FASB issued ASU 2016-01, “Recognition and Measurement of Financial Assets and Financial Liabilities.”	This ASU requires that most equity investments be measured at fair value, with subsequent changes in fair value recognized in net income. Under this new guidance, Nasdaq will no longer be able to recognize unrealized holding gains and losses on equity securities classified today as available-for-sale in accumulated other comprehensive income within stockholders’ equity. For certain equity investments that do not have readily determinable fair values, there is a new measurement alternative where those investments are measured at cost, less any impairment, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer. This new standard does not change the guidance for classifying and measuring investments in debt securities and loans. This new guidance also impacts financial liabilities accounted for under the fair value option and affects the presentation and disclosure requirements for financial assets and liabilities.	We adopted this standard on January 1, 2018 on a prospective basis.	Since we do not have a significant investment in financial instruments impacted by this standard at the time of adoption, there was no material impact on our consolidated financial statements. We have elected the measurement alternative for equity investments which were historically accounted for under the cost method of accounting. This could result in volatility in earnings.



Accounting Standard	Description	Effective Date	Effect on the Financial Statements or Other Significant Matters
Income Statement - Reporting Comprehensive Income In February 2018, the FASB issued ASU 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income.”	This ASU provides an election to reclassify tax effects that are stranded in accumulated other comprehensive income as a result of tax reform to retained earnings. An election is also available to reclassify other stranded tax effects that relate to the Tax Cuts and Jobs Act but do not directly relate to the change in the federal rate. Tax effects that are stranded in accumulated other comprehensive income for other reasons (e.g., prior changes in tax law, a change in valuation allowance) may not be reclassified. Previously, the effects of changes in tax rates and laws on deferred tax balances were required to be recorded as a component of tax expense related to continuing operations for the period in which the law was enacted, even if the assets and liabilities related to items of accumulated other comprehensive income. In other words, backward tracing of the income tax effects of items originally recognized through accumulated other comprehensive income was prohibited.	January 1, 2019, with early adoption permitted.	We are currently assessing the impact that this standard will have on our consolidated financial statements.
Revenue From Contracts With Customers In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes the revenue recognition guidance in Accounting Standards Codification, “Revenue Recognition.”	The new revenue recognition standard sets forth a five-step revenue recognition model to determine when and how revenue is recognized. The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration it expects to receive in exchange for those goods or services. The standard also requires more detailed disclosures. The standard provides alternative methods of initial adoption.	We adopted this standard on January 1, 2018 using the full retrospective method.	See discussion below.

The following tables present the expected effect of the adoption of Topic 606 on our Consolidated Statements of Income for the years ended December 31, 2017 and 2016:



	Year Ended December 31, 2017							Year Ended December 31, 2016
	As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted		As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted
	(in millions)							(in millions)
Revenues less transaction-based expenses:
Market Services	$	881	$	—		$	881	$	827	$	—		$	827
Corporate Services	656		(3		)	653		635		(3		)	632
Information Services	588		—			588		540		—			540
Market Technology	303		(14		)	289		275		2			277
Total revenues less transaction-based expenses	2,428		(17		)	2,411		2,277		(1		)	2,276

Total operating expenses ⁽¹⁾	1,429		(9		)	1,420		1,438		2			1,440

Income before income taxes	880		(8		)	872		136		(3		)	133
Income tax provision (benefit)	146		(3		)	143		28		(1		)	27
Net income attributable to Nasdaq	$	734	$	(5	)	$	729	$	108	$	(2	)	$	106
Diluted earnings per share	$	4.33	$	(0.03	)	$	4.30	$	0.64	$	(0.01	)	$	0.63

____________

⁽¹⁾ Adjustment to reflect the adoption of Topic 606 for the year ended December 31, 2017 and 2016 primarily pertains to our Market Technology business.



	December 31, 2017							December 31, 2016
	As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted		As Reported		Adjustment to Reflect Adoption of Topic 606			As Adjusted
	(in millions)							(in millions)
Assets:
Other current assets	$	187	$	(19	)	$	168	$	167	$	(15	)	$	152
Other non-current assets	412		(38		)	374		390		(46		)	344
Deferred tax assets	391		2			393		717		(1		)	716
Total assets	$	15,786	$	(55	)	$	15,731	$	14,150	$	(62	)	$	14,088

Liabilities:
Deferred revenue	$	189	$	(28	)	$	161	$	162	$	(24	)	$	138
Non-current deferred revenue	146		(20		)	126		171		(36		)	135
Total liabilities	$	9,899	$	(48	)	$	9,851	$	8,720	$	(60	)	$	8,660

Nasdaq stockholders' equity:
Retained earnings	$	3,970	$	(7	)	$	3,963	$	3,479	$	(2	)	$	3,477
Total Nasdaq stockholders' equity	5,887		(7		)	5,880		5,430		(2		)	5,428
Total liabilities and equity	$	15,786	$	(55	)	$	15,731	$	14,150	$	(62	)	$	14,088

Restructuring Charges (Tables)

12 Months Ended

Dec. 31, 2017

Restructuring and Related Activities [Abstract]

Summary of Restructuring Charges

The following table presents a summary of restructuring plan charges in the Consolidated Statements of Income:



	Year Ended December 31,
	2016		2015
	(in millions)
Rebranding of trade name	$	—	$	119
Severance	22		25
Facilities-related	1		—
Asset impairments	8		18
Other	10		10
Total restructuring charges	$	41	$	172

Acquisitions (Tables)

12 Months Ended

Dec. 31, 2017

Business Combinations [Abstract]

Schedule of Business Acquisitions, by Acquisition

2016 Acquisitions



	Purchase Consideration		Total Net Assets (Liabilities) Acquired			Total Net Deferred Tax Liability			Acquired Intangible Assets		Goodwill
	(in millions)
ISE	$	1,070	$	83		$	(185	)	$	623	$	549
Boardvantage	242		28			(38		)	111		141
Marketwired	111		(1		)	(5		)	31		86
Nasdaq Canada	116		6			(20		)	76		54

2017 Acquisitions



	Purchase Consideration		Total Net Liabilities Acquired			Total Net Deferred Tax Liability			Acquired Intangible Assets		Goodwill
	(in millions)
eVestment	$	744	$	(10	)	$	(104	)	$	405	$	453

2015 Acquisitions



	Purchase Consideration		Total Net Assets Acquired		Total Net Deferred Tax Liability			Acquired Intangible Assets		Goodwill
	(in millions)
DWA	$	226	$	8	$	(34	)	$	141	$	111

Acquired infinite lived intangible assets in acquisition

The following table presents the details of acquired intangible assets at the date of each acquisition. All acquired intangible assets with finite lives are amortized using the straight-line method.



	2017			2016												2015
	eVestment			ISE			Boardvantage			Marketwired			Nasdaq Canada			DWA
				($ in millions)
Intangible Assets
Exchange registrations	$	—		$	467		$	—		$	—		$	—		$	—
Discount rate used	—			8.6		%	—			—			—			—
Estimated average useful life	—			Indefinite			—			—			—			—
Customer relationships	$	378		$	148		$	103		$	29		$	76		$	29
Discount rate used	9.3		%	9.1		%	15.5		%	16.4		%	10.3		%	17.5		%
Estimated average useful life	14 years			13 years			14 years			6 years			17 years			15 years
Trade name	$	13		$	8		$	2		$	2		$	—		$	108
Discount rate used	9.2		%	8.6		%	15.0		%	15.8		%	—			17.0		%
Estimated average useful life	8 years			Indefinite			1 year			2 years			—			Indefinite
Technology	$	14		$	—		$	6		$	—		$	—		$	4
Discount rate used	9.2		%	—			15.5		%	—			—			17.0		%
Estimated average useful life	8 years			—			5 years			—			—			5 years
Total intangible assets	$	405		$	623		$	111		$	31		$	76		$	141

Acquired finite lived intangible assets in acquisition

The following table presents the details of acquired intangible assets at the date of each acquisition. All acquired intangible assets with finite lives are amortized using the straight-line method.



	2017			2016												2015
	eVestment			ISE			Boardvantage			Marketwired			Nasdaq Canada			DWA
				($ in millions)
Intangible Assets
Exchange registrations	$	—		$	467		$	—		$	—		$	—		$	—
Discount rate used	—			8.6		%	—			—			—			—
Estimated average useful life	—			Indefinite			—			—			—			—
Customer relationships	$	378		$	148		$	103		$	29		$	76		$	29
Discount rate used	9.3		%	9.1		%	15.5		%	16.4		%	10.3		%	17.5		%
Estimated average useful life	14 years			13 years			14 years			6 years			17 years			15 years
Trade name	$	13		$	8		$	2		$	2		$	—		$	108
Discount rate used	9.2		%	8.6		%	15.0		%	15.8		%	—			17.0		%
Estimated average useful life	8 years			Indefinite			1 year			2 years			—			Indefinite
Technology	$	14		$	—		$	6		$	—		$	—		$	4
Discount rate used	9.2		%	—			15.5		%	—			—			17.0		%
Estimated average useful life	8 years			—			5 years			—			—			5 years
Total intangible assets	$	405		$	623		$	111		$	31		$	76		$	141

Assets and Liabilities Held For Sale Assets and Liabilities Held For Sale (Tables)

12 Months Ended

Dec. 31, 2017

Discontinued Operations and Disposal Groups [Abstract]

Schedule of carrying amounts of assets and liabilities classified as held for sale

The following table presents the carrying amounts of the major classes of assets and liabilities classified as held for sale in the Consolidated Balance Sheets:



	December 31, 2017
	(in millions)
Receivables, net	$	27
Property and equipment, net	21
Goodwill⁽¹⁾	202
Intangible assets, net	38
Other assets	9
Total assets held for sale	$	297

Deferred tax liabilities	$	16
Other current liabilities	29
Total liabilities held for sale	$	45

____________

⁽¹⁾ The assignment of goodwill was based on the relative fair value of the disposal group and the portion of the remaining reporting unit.

Goodwill and Acquired Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes in Goodwill

The following table presents the changes in goodwill by business segment during the year ended December 31, 2017:



	Market Services		Corporate Services			Information Services		Market Technology		Total
	(in millions)
Balance at December 31, 2016	$	3,390	$	674		$	1,806	$	157	$	6,027
Goodwill acquired	—		—			453		13		466
Measurement period adjustment	—		(7		)	—		—		(7		)
Foreign currency translation adjustment	156		25			103		18		302
Goodwill reclassified as held for sale⁽¹⁾	—		(202		)	—		—		(202		)
Balance at December 31, 2017	$	3,546	$	490		$	2,362	$	188	$	6,586

____________

⁽¹⁾ See Note 5, “Assets and Liabilities Held for Sale,” for further discussion.

Schedule of Acquired Finite-Lived Intangible Assets

The following table presents details of our total acquired intangible assets, both finite- and indefinite-lived:



	December 31, 2017										December 31, 2016
	Gross Amount			Accumulated Amortization			Net Amount			Weighted-Average Useful Life (in Years)	Gross Amount			Accumulated Amortization			Net Amount			Weighted-Average Useful Life (in Years)
	(in millions)										(in millions)
Finite-Lived Intangible Assets
Technology	$	65		$	(22	)	$	43		8	$	38		$	(24	)	$	14		5
Customer relationships	1,708			(526		)	1,182			18	1,394			(464		)	930			18
Other	17			(4		)	13			8	7			(6		)	1			6
Foreign currency translation adjustment	(111		)	46			(65		)		(160		)	58			(102		)
Total finite-lived intangible assets	$	1,679		$	(506	)	$	1,173			$	1,279		$	(436	)	$	843
Indefinite-Lived Intangible Assets
Exchange and clearing registrations	$	1,257		$	—		$	1,257			$	1,257		$	—		$	1,257
Trade names	129			—			129				130			—			130
Licenses	52			—			52				52			—			52
Foreign currency translation adjustment	(143		)	—			(143		)		(188		)	—			(188		)
Total indefinite-lived intangible assets	$	1,295		$	—		$	1,295			$	1,251		$	—		$	1,251
Total intangible assets	$	2,974		$	(506	)	$	2,468			$	2,530		$	(436	)	$	2,094

Schedule of Acquired Indefinite-lived Intangible Assets

The following table presents details of our total acquired intangible assets, both finite- and indefinite-lived:



	December 31, 2017										December 31, 2016
	Gross Amount			Accumulated Amortization			Net Amount			Weighted-Average Useful Life (in Years)	Gross Amount			Accumulated Amortization			Net Amount			Weighted-Average Useful Life (in Years)
	(in millions)										(in millions)
Finite-Lived Intangible Assets
Technology	$	65		$	(22	)	$	43		8	$	38		$	(24	)	$	14		5
Customer relationships	1,708			(526		)	1,182			18	1,394			(464		)	930			18
Other	17			(4		)	13			8	7			(6		)	1			6
Foreign currency translation adjustment	(111		)	46			(65		)		(160		)	58			(102		)
Total finite-lived intangible assets	$	1,679		$	(506	)	$	1,173			$	1,279		$	(436	)	$	843
Indefinite-Lived Intangible Assets
Exchange and clearing registrations	$	1,257		$	—		$	1,257			$	1,257		$	—		$	1,257
Trade names	129			—			129				130			—			130
Licenses	52			—			52				52			—			52
Foreign currency translation adjustment	(143		)	—			(143		)		(188		)	—			(188		)
Total indefinite-lived intangible assets	$	1,295		$	—		$	1,295			$	1,251		$	—		$	1,251
Total intangible assets	$	2,974		$	(506	)	$	2,468			$	2,530		$	(436	)	$	2,094

Schedule of Finite-Lived Intangible Assets

The following table presents the gross amount, accumulated amortization and net amount of finite-lived and indefinite-lived intangible assets that have been reclassified as assets held for sale as of December 31, 2017. See Note 5, “Assets and Liabilities Held for Sale,” for further discussion.



	Gross Amount		Accumulated Amortization			Net Amount
	(in millions)
Finite-lived intangible assets reclassified as held for sale:
Customer relationships	$	54	$	(17	)	$	37
Other	2		(1		)	1
Total finite-lived intangible assets held for sale	$	56	$	(18	)	$	38

Estimated Future Amortization Expense



	(in millions)
2018	$	114
2019	99
2020	99
2021	97
2022	94
2023 and thereafter	735
Total	$	1,238

Property and Equipment, net (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment, Net

The following table presents our major categories of property and equipment, net:



	Year Ended December 31,
	2017			2016
	(in millions)
Data processing equipment and software	$	626		$	665
Furniture, equipment and leasehold improvements	279			254
Total property and equipment	905			919
Less: accumulated depreciation and amortization	(505		)	(557		)
Total property and equipment, net	$	400		$	362

Deferred Revenue (Tables)

12 Months Ended

Dec. 31, 2017

Deferred Revenue Disclosure [Abstract]

Changes in Deferred Revenue

The changes in our deferred revenue during the year ended December 31, 2017 and 2016 are reflected in the following table:



	Initial Listing Revenues			Listing of Additional Shares Revenues			Annual Renewal and Other Revenues			Market Technology Revenues			Total
	(in millions)
Balance at January 1, 2017	$	54		$	37		$	57		$	185		$	333
Additions	18			11			569			208			806
Revenue recognized	(17		)	(22		)	(544		)	(240		)	(823		)
Translation adjustment	—			—			1			20			21
Deferred revenue reclassified as held for sale⁽¹⁾	—			—			(2		)	—			(2		)
Balance at December 31, 2017	$	55		$	26		$	81		$	173		$	335

Balance at January 1, 2016	$	59		$	53		$	28		$	187		$	327
Additions	13			12			606			233			864
Revenue recognized	(18		)	(28		)	(576		)	(227		)	(849		)
Translation adjustment	—			—			(1		)	(8		)	(9		)
Balance at December 31, 2016	$	54		$	37		$	57		$	185		$	333

____________

⁽¹⁾ See Note 5, “Assets and Liabilities Held for Sale,” for further discussion.

Estimated Deferred Revenue

As of December 31, 2017, we estimate that our deferred revenue, which is primarily corporate services and market technology revenues, will be recognized in the following years:



	Initial Listing Revenues		Listing of Additional Shares Revenues		Annual Renewal and Other Revenues		Market Technology Revenues		Total
	(in millions)
Fiscal year ended:
2018	$	17	$	13	$	79	$	80	$	189
2019	15		7		2		35		59
2020	11		5		—		33		49
2021	7		1		—		15		23
2022	4		—		—		3		7
2023 and thereafter	1		—		—		7		8
	$	55	$	26	$	81	$	173	$	335

Debt Obligations (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Changes in Debt Obligations

The following table presents the changes in the carrying amount of our debt obligations during the year ended December 31, 2017:



	December 31, 2016		Additions		Payments, Accretion and Other			December 31, 2017
	(in millions)
Short-term debt - commercial paper	$	—	$	2,514	$	(2,034	)	$	480
Long-term debt:
5.55% senior unsecured notes due January 15, 2020	598		—		1			599
5.25% senior unsecured notes repaid on May 26, 2017	369		—		(369		)	—
3.875% senior unsecured notes due June 7, 2021	625		—		91			716
4.25% senior unsecured notes due June 1, 2024	495		—		1			496
1.75% senior unsecured notes due May 19, 2023	622		—		90			712
3.85% senior unsecured notes due June 30, 2026	495		—		1			496
Senior unsecured floating rate notes due March 22, 2019	—		498		—			498
$400 million senior unsecured term loan facility due November 25, 2019 (average interest rate of 2.47% for the period January 1, 2017 through December 31, 2017)	399		—		(299		)	100
$1 billion revolving credit commitment due April 25, 2022 (average interest rate of 2.66% for the period April 25, 2017 through December 31, 2017)	—		155		(45		)	110
Total long-term debt	3,603		653		(529		)	3,727
Total debt obligations	$	3,603	$	3,167	$	(2,563	)	$	4,207

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2017

Income Tax Disclosure [Abstract]

Components of Income Tax Provision

The income tax provision consists of the following amounts:



	Year Ended December 31,
	2017			2016			2015
	(in millions)
Current income taxes:
Federal	$	51		$	37		$	139
State	17			21			42
Foreign	68			106			36
Total current income taxes	136			164			217
Deferred income taxes:
Federal	(14		)	(97		)	(18		)
State	24			(35		)	(1		)
Foreign	—			(4		)	5
Total deferred income taxes	10			(136		)	(14		)
Total income tax provision	$	146		$	28		$	203

Reconciliation of Provision of Income Taxes

A reconciliation of the income tax provision, based on the U.S. federal statutory rate, to our actual income tax provision for the years ended December 31, 2017, 2016 and 2015 is as follows:



	Year Ended December 31,
	2017		2016		2015
Federal income tax provision at the statutory rate	35.0	%	35.0	%	35.0	%
State income tax provision, net of federal effect	2.6	%	(6.7	)%	3.9	%
Change in deferred taxes due to change in law	(9.9	)%	(1.2	)%	0.2	%
Excess tax benefits related to employee share-based compensation	(4.0	)%	—	%	—	%
Non-U.S. subsidiary earnings	(6.0	)%	(7.3	)%	(6.4	)%
Tax credits and deductions	(1.0	)%	(5.1	)%	(0.8	)%
Change in unrecognized tax benefits	(0.8	)%	4.2	%	0.3	%
Other, net	0.7	%	1.7	%	—	%
Actual income tax provision	16.6	%	20.6	%	32.2	%

Schedule of Deferred Tax Assets and Liabilities

The temporary differences, which give rise to our deferred tax assets and (liabilities), consisted of the following:



	December 31,
	2017			2016
	(in millions)
Deferred tax assets:
Deferred revenues	$	25		$	39
U.S. federal net operating loss	1			2
Foreign net operating loss	30			37
State net operating loss	4			1
Compensation and benefits	42			99
Foreign currency translation	292			528
Tax credits	7			7
Other	20			34
Gross deferred tax assets	$	421		$	747

Deferred tax liabilities:
Amortization of software development costs and depreciation	$	(47	)	$	(63	)
Amortization of acquired intangible assets	(510		)	(596		)
Investments	(26		)	(37		)
Other	(19		)	(24		)
Gross deferred tax liabilities	(602		)	(720		)
Net deferred tax assets before valuation allowance	(181		)	27
Less: valuation allowance	(30		)	(30		)
Net deferred tax assets (liabilities)	$	(211	)	$	(3	)

Summary of Net Operating Losses and Credits

As of December 31, 2017, the expiration dates for the NOLs, and credits are as follows:



Jurisdiction	Amount		Expiration Date
	(in millions)
U.S. Federal NOL	$	1	2033-2035
Foreign NOL	4		2018-2026
Foreign NOL	26		No expiration date
State NOL	4		2025-2036
U.S. Federal Tax credits	7		2018-2027

Summary of Tax Credit Carryforwards

As of December 31, 2017, the expiration dates for the NOLs, and credits are as follows:



Jurisdiction	Amount		Expiration Date
	(in millions)
U.S. Federal NOL	$	1	2033-2035
Foreign NOL	4		2018-2026
Foreign NOL	26		No expiration date
State NOL	4		2025-2036
U.S. Federal Tax credits	7		2018-2027

Domestic and Foreign Components of Income Before Income Tax Provision

The following represents the domestic and foreign components of income before income tax provision:



	Year Ended December 31,
	2017		2016			2015
	(in millions)
Domestic	$	556	$	(155	)	$	393
Foreign	324		291			237
Income before income tax provision	$	880	$	136		$	630

Reconciliation of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:



	Year Ended December 31,
	2017			2016
	(in millions)
Beginning balance	$	48		$	40
Additions as a result of tax positions taken in prior periods	2			9
Additions as a result of tax positions taken in the current period	5			3
Reductions related to settlements with taxing authorities	—			(4		)
Reductions as a result of lapses of the applicable statute of limitations	(10		)	—
Ending balance	$	45		$	48

Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Share-Based Compensation Expense



	Year Ended December 31,
	2017			2016			2015
	(in millions)
Share-based compensation expense before income taxes	$	70		$	86		$	68
Income tax benefit	(29		)	(35		)	(28		)
Share-based compensation expense after income taxes	$	41		$	51		$	40

Summary of Restricted Stock Activity

The following table summarizes our restricted stock activity for the years ended December 31, 2017, 2016 and 2015:



	Restricted Stock
	Number of Awards		Weighted-Average Grant Date Fair Value
Unvested balances at December 31, 2014	3,193,230		$	30.99
Granted	823,950		$	49.26
Vested	(370,998	)	$	29.90
Forfeited	(302,444	)	$	34.34
Unvested balances at December 31, 2015	3,343,738		$	35.36
Granted	724,200		$	62.91
Vested	(1,238,980	)	$	27.91
Forfeited	(268,380	)	$	43.29
Unvested balances at December 31, 2016	2,560,578		$	45.92
Granted	737,864		$	67.48
Vested	(1,102,823	)	$	38.56
Forfeited	(207,119	)	$	52.29
Unvested balances at December 31, 2017	1,988,500		$	57.34

Schedule of Weighted-Average Assumptions Used to Determine the Weighted-Average Fair Values



	Year Ended December 31,
	2017		2016
Weighted-average risk free interest rate⁽¹⁾	1.44	%	0.84	%
Expected volatility⁽²⁾	19.2	%	21.0	%
Weighted-average grant date share price	$69.45		$66.36
Weighted-average fair value at grant date	$81.57		$93.25

____________


⁽¹⁾	The risk-free interest rate for periods within the expected life of the award is based on the U.S. Treasury yield curve in effect at the time of grant.


⁽²⁾	We use historic volatility for PSU awards issued under the three-year PSU program, as implied volatility data could not be obtained for all the companies in the peer groups used for relative performance measurement within the program.

Summary of PSU Activity

The following table summarizes our PSU activity for the years ended December 31, 2017, 2016 and 2015:



	PSUs
	One-Year Program				Three-Year Program
	Number of Awards		Weighted-Average Grant Date Fair Value		Number of Awards		Weighted-Average Grant Date Fair Value
Unvested balances at December 31, 2014	558,040		$	24.17	1,654,567		$	35.57
Granted	206,199		$	48.16	649,626		$	49.69
Vested	(247,273	)	$	30.51	(837,109	)	$	22.50
Forfeited	(92,999	)	$	34.74	(27,366	)	$	43.49
Unvested balances at December 31, 2015	423,967		$	41.34	1,439,718		$	49.41
Granted	242,642		$	58.33	761,501		$	66.89
Vested	(242,793	)	$	39.63	(879,926	)	$	43.81
Forfeited	(45,050	)	$	47.72	(6,625	)	$	69.11
Unvested balances at December 31, 2016	378,766		$	52.55	1,314,668		$	63.18
Granted	197,075		$	65.51	803,712		$	55.57
Vested	(202,073	)	$	49.93	(1,079,925	)	$	42.83
Forfeited	(40,764	)	$	55.92	(28,497	)	$	87.86
Unvested balances at December 31, 2017	333,004		$	61.39	1,009,958		$	78.18

Summary of Stock Option Activity

A summary of stock option activity for the year ended December 31, 2017 is as follows:



	Number of Stock Options		Weighted-Average Exercise Price

Outstanding at December 31, 2014	3,316,782		$	27.56
Exercised	(682,054	)	26.84
Forfeited	(8,241	)	28.53
Outstanding at December 31, 2015	2,626,487		$	27.74
Exercised	(1,219,820	)	34.00
Forfeited	(296	)	23.31
Outstanding at December 31, 2016	1,406,371		$	22.32
Granted	268,817		66.68
Exercised	(1,102,830	)	21.98
Forfeited	(978	)	21.33
Outstanding at December 31, 2017	571,380		$	43.84
Exercisable at December 31, 2017	302,563		$	23.55

Schedule of Outstanding and Exercisable Stock Options

The following table summarizes significant ranges of outstanding and exercisable stock options as of December 31, 2017:



			Outstanding						Exercisable
Range of Exercise Prices			Number of Stock Options	Weighted-Average Remaining Contractual Term (in years)	Weighted-Average Exercise Price		Aggregate Intrinsic Value (in millions)		Number Exercisable	Weighted-Average Remaining Contractual Term (in years)	Weighted-Average Exercise Price		Aggregate Intrinsic Value (in millions)
$17.36	-	$19.99	94,265	2.14	$	19.73	$	5	94,265	2.14	$	19.73	$	5
$20.00	-	$25.75	206,980	2.39	25.20		11		206,980	2.39	25.20		11
$25.76	-	$66.68	270,135	8.84	66.53		3		1,318	0.48	36.40		—
Total			571,380	5.40	$	43.84	$	19	302,563	2.30	$	23.55	$	16

Schedule of Employee Stock Purchase Plan, Activity

The following table summarizes employee activity and expense associated with the ESPP for the years ended December 31, 2017, 2016 and 2015.



	Year Ended December 31,
	2017		2016		2015
Number of shares purchased by employees	235,859		233,464		247,444
Weighted-average price of shares purchased	$	58.26	$	50.39	$	40.95
Compensation expense (in millions)	$	3	$	4	$	4

Nasdaq Stockholders’ Equity (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Common Stock in Treasury, at Cost

The following table summarizes our share repurchase activity:



	Year Ended December 31,
	2017		2016
Number of shares of common stock repurchased	2,843,519		1,547,778
Average price paid per share	$	71.56	$	64.42
Total purchase price (in millions)	$	203	$	100

Schedule of Dividends Declared

During 2017, our board of directors declared the following cash dividends:



Declaration Date	Dividend Per Common Share		Record Date	Total Amount Paid		Payment Date
				(in millions)
January 30, 2017	$	0.32	March 17, 2017	$	53	March 31, 2017
April 25, 2017	0.38		June 16, 2017	63		June 30, 2017
July 25, 2017	0.38		September 15, 2017	64		September 29, 2017
October 24, 2017	0.38		December 15, 2017	63		December 29, 2017
				$	243

Schedule of Accumulated Other Comprehensive Income (Loss)

Accumulated Other Comprehensive Loss

The following table outlines the components of accumulated other comprehensive loss:



	Foreign Currency Translation Adjustments			Employee Benefit Plan Adjustments			Accumulated Other Comprehensive Loss
	(in millions)
Gross balance, December 31, 2016	$	(1,481	)	$	(35	)	$	(1,516	)
Income taxes	523			14			537
Net balance, December 31, 2016	$	(958	)	$	(21	)	$	(979	)

Gross balance, December 31, 2017	$	(1,268	)	$	(37	)	$	(1,305	)
Income taxes	428			15			443
Net balance, December 31, 2017	$	(840	)	$	(22	)	$	(862	)

Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Summary of Computation of Basic and Diluted Earnings Per Share

The following table sets forth the computation of basic and diluted earnings per share:



	Year Ended December 31,
	2017		2016		2015
	(in millions, except share and per share amounts)
Numerator:
Net income attributable to common shareholders	$	734	$	108	$	428
Denominator:
Weighted-average common shares outstanding for basic earnings per share	166,364,299		165,182,290		167,285,450
Weighted-average effect of dilutive securities:
Employee equity awards	2,861,892		3,258,136		3,638,981
Contingent issuance of common stock	358,840		360,571		358,840
Weighted-average common shares outstanding for diluted earnings per share	169,585,031		168,800,997		171,283,271
Basic and diluted earnings per share:
Basic earnings per share	$	4.41	$	0.65	$	2.56
Diluted earnings per share	$	4.33	$	0.64	$	2.50

Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2017

Fair Value Disclosures [Abstract]

Schedule of Financial Assets Measured at Fair Value on Recurring Basis



	December 31, 2017
	Total		Level 1		Level 2		Level 3
	(in millions)
Financial investments, at fair value	$	235	$	135	$	100	$	—
Default fund and margin deposit investments	2,129		371		1,758		—
Total	$	2,364	$	506	$	1,858	$	—



	December 31, 2016
	Total		Level 1		Level 2		Level 3
	(in millions)
Financial investments, at fair value	$	245	$	151	$	94	$	—
Default fund and margin deposit investments	1,900		614		1,286		—
Total	$	2,145	$	765	$	1,380	$	—

Clearing Operations (Tables)

12 Months Ended

Dec. 31, 2017

Due to and from Broker-Dealers and Clearing Organizations [Abstract]

Schedule of Clearing Member Default Fund Contributions

As of December 31, 2017, clearing member default fund contributions and margin deposits were as follows:



	December 31, 2017
	Cash Contributions		Non-Cash Contributions		Total Contributions
	(in millions)
Default fund contributions	$	360	$	130	$	490
Margin deposits	3,628		4,047		7,675
Total	$	3,988	$	4,177	$	8,165

Schedule of Derivative Contracts Outstanding

The market value of derivative contracts outstanding prior to netting was as follows:



	December 31, 2017
	(in millions)
Commodity and seafood options, futures and forwards^(1)(2)(3)	$	524
Fixed-income options and futures⁽¹⁾⁽²⁾	729
Stock options and futures⁽¹⁾⁽²⁾	132
Index options and futures⁽¹⁾⁽²⁾	111
Total	$	1,496

____________


⁽¹⁾	We determined the fair value of our option contracts using standard valuation models that were based on market-based observable inputs including implied volatility, interest rates and the spot price of the underlying instrument.


⁽²⁾	We determined the fair value of our futures contracts based upon quoted market prices and average quoted market yields.


⁽³⁾	We determined the fair value of our forward contracts using standard valuation models that were based on market-based observable inputs including LIBOR rates and the spot price of the underlying instrument.

Schedule of Derivative Contracts Cleared

The total number of derivative contracts cleared through Nasdaq Clearing for the years ended December 31, 2017 and 2016 was as follows:



	December 31, 2017	December 31, 2016
Commodity and seafood options, futures and forwards⁽¹⁾	2,824,188	3,530,746
Fixed-income options and futures	20,376,383	14,639,065
Stock options and futures	26,023,816	28,496,143
Index options and futures	44,928,284	50,636,527
Total	94,152,671	97,302,481

____________


(1)	The total volume in cleared power related to commodity contracts was 1,199 Terawatt hours (TWh) for the year ended December 31, 2017 and 1,658 TWh for the year ended December 31, 2016.

- Definition

Tabular disclosure of pertinent information about a derivative or group of derivatives on a disaggregated basis, such as for individual instruments, or small groups of similar instruments. May include a combination of the type of instrument, risks being hedged, notional amount, hedge designation, related hedged item, inception date, maturity date, or other relevant item.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41641-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41678-113959

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41638-113959

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5580258-113959

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5579245-113959

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5579240-113959

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41620-113959

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(n)(2))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Business Segments (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Schedule of Operating Segments

The following table presents certain information regarding our operating segments for the years ended December 31, 2017, 2016 and 2015 :



	Market Services			Corporate Services		Information Services		Market Technology		Corporate Items			Consolidated
	(in millions)
2017
Total revenues	$	2,418		$	656	$	588	$	303	$	—		$	3,965
Transaction-based expenses	(1,537		)	—		—		—		—			(1,537		)
Revenues less transaction-based expenses	881			656		588		303		—			2,428
Depreciation and amortization	95			49		25		$	19	—			188
Operating income (loss)	481			184		418		$	65	(149		)	999
Total assets	9,471			866		3,420		627		1,402			15,786
Purchase of property and equipment	59			41		10		34		—			144
2016
Total revenues	$	2,255		$	635	$	540	$	275	$	—		$	3,705
Transaction-based expenses	(1,428		)	—		—		—		—			(1,428		)
Revenues less transaction-based expenses	827			635		540		275		—			2,277
Depreciation and amortization	87			47		18		18		—			170
Operating income (loss)	450			158		383		69		(221		)	839
Total assets	8,626			1,263		2,439		559		1,263			14,150
Purchase of property and equipment	62			37		8		27		—			134
2015
Total revenues	$	2,084		$	562	$	512	$	245	$	—		$	3,403
Transaction-based expenses	(1,313		)	—		—		—		—			(1,313		)
Revenues less transaction-based expenses	771			562		512		245		—			2,090
Depreciation and amortization	64			42		14		18		—			138
Operating income (loss)	413			140		365		58		(256		)	720
Total assets	6,906			576		2,456		752		1,171			11,861
Purchase of property and equipment	53			38		11		31		—			133

Schedule of Corporate Items

A summary of our corporate items is as follows:



	Year Ended December 31,
	2017		2016			2015
	(in millions)
Amortization expense of acquired intangible assets	$	92	$	82		$	62
Merger and strategic initiatives expense	44		76			10
Restructuring charges	—		41			172
Loss on extinguishment of debt	10		—			—
Regulatory matter	1		6			—
Sublease loss reserve	2		(1		)	—
Reversal of VAT refund receivables	—		—			12
Executive compensation	—		12			—
Other	—		5			—
Total	$	149	$	221		$	256

Revenue from External Customers by Geographic Areas



	Total Revenues		Property and Equipment, Net
	(in millions)
2017:
United States	$	3,062	$	247
All other countries	903		153
Total	$	3,965	$	400

2016:
United States	$	2,659	$	244
All other countries	1,046		118
Total	$	3,705	$	362

2015:
United States	$	2,408	$	217
All other countries	995		106
Total	$	3,403	$	323

Property and Equipment, Net by Geographic Area



	Total Revenues		Property and Equipment, Net
	(in millions)
2017:
United States	$	3,062	$	247
All other countries	903		153
Total	$	3,965	$	400

2016:
United States	$	2,659	$	244
All other countries	1,046		118
Total	$	3,705	$	362

2015:
United States	$	2,408	$	217
All other countries	995		106
Total	$	3,403	$	323

Organization and Nature of Operations (Details) $ in Billions	12 Months Ended
	Dec. 31, 2017 USD ($) marketplace segment company exchange exchange_traded_product country
Organization And Basis Of Presentation [Line Items]
Number of operating segments \| segment	4
Market Services
Organization And Basis Of Presentation [Line Items]
Number of derivative exchanges listing commodities offerings	2
Market Services \| United States \| Options Markets
Organization And Basis Of Presentation [Line Items]
Number of exchanges	6
Market Services \| United States \| Cash Equities Trading Markets
Organization And Basis Of Presentation [Line Items]
Number of exchanges	3
Market Services \| Canada
Organization And Basis Of Presentation [Line Items]
Number of exchanges	3
Corporate Services
Organization And Basis Of Presentation [Line Items]
Total number of listing on The Nasdaq Stock Market \| company	2,949
ETPs and other listings listed on Nasdaq Stock Market \| company	373
Approximate combined market capitalization, U.S. \| $	$ 11,600
Total number of listed companies within Nordic and Baltic exchanges \| company	984
Approximate combined market capitalization within Nordic and Baltic exchanges \| $	$ 1,500
Information Services
Organization And Basis Of Presentation [Line Items]
Number of exchange traded products licensed to Nasdaq's Indexes \| exchange_traded_product	324
Assets management value \| $	$ 167
Market Technology
Organization And Basis Of Presentation [Line Items]
Number of exchanges \| marketplace	90
Number of countries services are provided \| country	50

- Summary of Significant Accounting Policies (Details)	12 Months Ended
- Summary of Significant Accounting Policies (Details)	Dec. 31, 2017 USD ($) agreement	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and cash equivalents	$ 377,000,000	$ 403,000,000
Restricted cash	22,000,000	15,000,000
Allowance for doubtful accounts receivable	9,000,000	13,000,000	$ 14,000,000
Goodwill, impairment loss	0	0	0
Impairment of intangible assets, indefinite-lived (excluding goodwill)	$ 0
Cost method investment, ownership percentage	20.00%
Initial listing
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Listings estimated useful life	6 years
Additional shares listing
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Listings estimated useful life	4 years
Initial Listing Revenues
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Listings estimated useful life	6 years
Listing of Additional Shares Revenues
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Listings estimated useful life	4 years
Accounting Standards Update 2016-09, Excess Tax Benefit Component
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Excess tax benefits recorded	$ 40,000,000
Cash equivalents
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Maturities	90 days
Cash and cash equivalents	$ 183,000,000	251,000,000
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue recognition period	1 year
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenue recognition period	2 years
Buildings and improvements \| Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful life	10 years
Buildings and improvements \| Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful life	40 years
Data processing equipment and software \| Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful life	2 years
Data processing equipment and software \| Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful life	5 years
Furniture and equipment \| Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful life	5 years
Furniture and equipment \| Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Property, plant and equipment, useful life	10 years
Computer Software \| Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Finite-lived intangible asset, useful life	3 years
Computer Software \| Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Finite-lived intangible asset, useful life	5 years
Other
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impairment of intangible assets, indefinite-lived (excluding goodwill)		0	0
Rebranding of trade name
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Impairment of intangible assets, indefinite-lived (excluding goodwill)		$ 578,000,000	$ 119,000,000
Corporate Services
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of types of license agreements \| agreement	2
Employee Stock Purchase Plan
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Percentage of fair market value of common stock	85.00%
Discount given to employees	15.00%

Summary of Significant Accounting Policies - Summary of Significant Accounting Policies - Effect of Topic 606 (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues Less Transaction-based Expenses [Abstract]
Market Services	$ 2,418	$ 2,255	$ 2,084
Corporate Services	656	635	562
Information Services	588	540	512
Market Technology	303	275	245
Revenues less transaction-based expenses	2,428	2,277	2,090
Total operating expenses	1,429	1,438	1,370
Income before income taxes	880	136	630
Income tax provision (benefit)	146	28	203
Net income	$ 734	$ 108	$ 427
Diluted earnings per share (in dollars per share)	$ 4.33	$ 0.64	$ 2.50
Assets
Other current assets	$ 187	$ 167
Other non-current assets	412	390
Deferred tax assets	391	717
Total assets	15,786	14,150	$ 11,861
Liabilities
Deferred revenue	189	162
Non-current deferred revenue	146	171
Total liabilities	9,899	8,720
Nasdaq stockholders' equity:
Retained earnings	3,970	3,479
Total Nasdaq stockholders’ equity	5,887	5,430
Total liabilities and equity	15,786	14,150
Pro Forma
Revenues Less Transaction-based Expenses [Abstract]
Market Services	881	827
Corporate Services	653	632
Information Services	588	540
Market Technology	289	277
Revenues less transaction-based expenses	2,411	2,276
Total operating expenses	1,420	1,440
Income before income taxes	872	133
Income tax provision (benefit)	143	27
Net income	$ 729	$ 106
Diluted earnings per share (in dollars per share)	$ 4.30	$ 0.63
Assets
Other current assets	$ 168	$ 152
Other non-current assets	374	344
Deferred tax assets	393	716
Total assets	15,731	14,088
Liabilities
Deferred revenue	161	138
Non-current deferred revenue	126	135
Total liabilities	9,851	8,660
Nasdaq stockholders' equity:
Retained earnings	3,963	3,477
Total Nasdaq stockholders’ equity	5,880	5,428
Total liabilities and equity	15,731	14,088
Accounting Standards Update 2014-09 \| Pro Forma \| Calculated under Revenue Guidance in Effect before Topic 606
Revenues Less Transaction-based Expenses [Abstract]
Market Services	881	827
Corporate Services	656	635
Information Services	588	540
Market Technology	303	275
Revenues less transaction-based expenses	2,428	2,277
Total operating expenses	1,429	1,438
Income before income taxes	880	136
Income tax provision (benefit)	146	28
Net income	$ 734	$ 108
Diluted earnings per share (in dollars per share)	$ 4.33	$ 0.64
Assets
Other current assets	$ 187	$ 167
Other non-current assets	412	390
Deferred tax assets	391	717
Total assets	15,786	14,150
Liabilities
Deferred revenue	189	162
Non-current deferred revenue	146	171
Total liabilities	9,899	8,720
Nasdaq stockholders' equity:
Retained earnings	3,970	3,479
Total Nasdaq stockholders’ equity	5,887	5,430
Total liabilities and equity	15,786	14,150
Accounting Standards Update 2014-09 \| Pro Forma \| Difference between Revenue Guidance in Effect before and after Topic 606
Revenues Less Transaction-based Expenses [Abstract]
Market Services	0	0
Corporate Services	(3)	(3)
Information Services	0	0
Market Technology	(14)	2
Revenues less transaction-based expenses	(17)	(1)
Total operating expenses	(9)	2
Income before income taxes	(8)	(3)
Income tax provision (benefit)	(3)	(1)
Net income	$ (5)	$ (2)
Diluted earnings per share (in dollars per share)	$ (0.03)	$ (0.01)
Assets
Other current assets	$ (19)	$ (15)
Other non-current assets	(38)	(46)
Deferred tax assets	2	(1)
Total assets	(55)	(62)
Liabilities
Deferred revenue	(28)	(24)
Non-current deferred revenue	(20)	(36)
Total liabilities	(48)	(60)
Nasdaq stockholders' equity:
Retained earnings	(7)	(2)
Total Nasdaq stockholders’ equity	(7)	(2)
Total liabilities and equity	$ (55)	$ (62)

Restructuring Charges (Narrative) (Details) $ in Millions	12 Months Ended
Restructuring Charges (Narrative) (Details) $ in Millions	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($) employee	Dec. 31, 2015 USD ($) employee	Jun. 30, 2016 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost				$ 213
Restructuring charges	$ 0	$ 41	$ 172
Severance
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 22	$ 25
Number of positions eliminated \| employee		201	230
Restructuring reserve		$ 17
Asset impairments
Restructuring Cost and Reserve [Line Items]
Restructuring charges		8	$ 18
Other
Restructuring Cost and Reserve [Line Items]
Restructuring charges		10	10
Rebranding of trade name
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 0	$ 119

Restructuring Charges (Summary of Restructuring Charges) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Total restructuring charges	$ 0	$ 41	$ 172
Rebranding of trade name
Restructuring Cost and Reserve [Line Items]
Total restructuring charges		0	119
Severance
Restructuring Cost and Reserve [Line Items]
Total restructuring charges		22	25
Facilities-related
Restructuring Cost and Reserve [Line Items]
Total restructuring charges		1	0
Asset impairments
Restructuring Cost and Reserve [Line Items]
Total restructuring charges		8	18
Other
Restructuring Cost and Reserve [Line Items]
Total restructuring charges		$ 10	$ 10

Acquisitions (2017 Acquisitions) (Details) - USD ($) $ in Millions	1 Months Ended
	Oct. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 6,586	$ 6,027
eVestment
Business Acquisition [Line Items]
Purchase Consideration	$ 744
Total Net Liabilities Acquired	(10)
Total Net Deferred Tax Liability	(104)
Acquired Intangible Assets, Finite-lived	405	$ 405
Goodwill	453
Cash consideration	705
Acquisition of businesses, net of cash and cash equivalents acquired	22
Purchase price allocation deferred tax assets	39
Purchase price allocation deferred tax liabilities	$ 143

Acquisitions (2016 Acquisitions) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	May 31, 2016	Feb. 29, 2016
Business Acquisition [Line Items]
Goodwill	$ 6,586	$ 6,027
ISE
Business Acquisition [Line Items]
Purchase Consideration			$ 1,070
Total Net Liabilities Acquired			83
Total Net Deferred Tax Liability			(185)
Acquired Intangible Assets		623	623
Goodwill			$ 549
Boardvantage
Business Acquisition [Line Items]
Purchase Consideration				$ 242
Total Net Liabilities Acquired				28
Total Net Deferred Tax Liability				(38)
Acquired Intangible Assets, Finite-lived		111		111
Goodwill				$ 141
Marketwired
Business Acquisition [Line Items]
Purchase Consideration					$ 111
Total Net Liabilities Acquired					(1)
Total Net Deferred Tax Liability					(5)
Acquired Intangible Assets, Finite-lived		31			31
Goodwill					86
Nasdaq Canada
Business Acquisition [Line Items]
Purchase Consideration					116
Total Net Liabilities Acquired					6
Total Net Deferred Tax Liability					(20)
Acquired Intangible Assets, Finite-lived		$ 76			76
Goodwill					$ 54

Acquisitions (2016 Acquisitions) (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended		12 Months Ended
	May 31, 2016	Feb. 29, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 31, 2017
Business Acquisition [Line Items]
Credit facility, proceeds					$ 150	$ 898	$ 506
Marketwired
Business Acquisition [Line Items]
Measurement period adjustment decrease to deferred tax liabilities				$ 5
Purchase Consideration		$ 111
Total Net Liabilities Acquired		(1)
Net deferred tax liability		5
Purchase price allocation deferred tax liabilities		10
Cash paid		109
Working capital adjustments		2
Marketwired \| Previous credit facility
Business Acquisition [Line Items]
Credit facility, proceeds		109
Boardvantage
Business Acquisition [Line Items]
Measurement period adjustment, increase to deferred tax assets			$ 7
Purchase Consideration	$ 242
Total Net Liabilities Acquired	28
Net deferred tax liability	38
Cash paid	197
Working capital adjustments	45
Boardvantage \| Previous credit facility
Business Acquisition [Line Items]
Credit facility, proceeds	197
eVestment
Business Acquisition [Line Items]
Purchase Consideration								$ 705
Total Net Liabilities Acquired								(10)
Net deferred tax liability								104
Purchase price allocation deferred tax liabilities								143
Purchase price allocation deferred tax assets								$ 39
ISE
Business Acquisition [Line Items]
Purchase Consideration				1,070
Total Net Liabilities Acquired				83
Net deferred tax liability				185
Purchase price allocation deferred tax liabilities				266
Purchase price allocation deferred tax assets				$ 81
Nasdaq Canada
Business Acquisition [Line Items]
Purchase Consideration		116
Total Net Liabilities Acquired		6
Net deferred tax liability		20
Cash paid		115
Working capital adjustments		1
Nasdaq Canada \| Previous credit facility
Business Acquisition [Line Items]
Credit facility, proceeds		$ 55
Scenario, Previously Reported \| Boardvantage
Business Acquisition [Line Items]
Purchase price allocation deferred tax liabilities	46
Purchase price allocation deferred tax assets	1
Scenario, Previously Reported \| eVestment
Business Acquisition [Line Items]
Net deferred tax liability	$ 45

Acquisitions Acquisitions (2015 Acquisitions) (Narrative) (Details) - USD ($) $ in Millions		12 Months Ended
	Jan. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 6,586	$ 6,027
Credit facility, proceeds		$ 150	$ 898	$ 506
Dorsey Wright Associates Llc Or Dwa
Business Acquisition [Line Items]
Purchase Consideration	$ 226
Total Net Liabilities Acquired	8
Total Net Deferred Tax Liability	(34)
Acquired Intangible Assets	141
Goodwill	111
Cash paid	225
Working capital adjustments	1
Dorsey Wright Associates Llc Or Dwa \| Revolving Credit Facility
Business Acquisition [Line Items]
Credit facility, proceeds	$ 100

Acquisitions (Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 31, 2017	Jun. 30, 2016	May 31, 2016	Feb. 29, 2016
Customer relationships
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Amortization period of intangible assets for tax purposes	15 years
Trade name
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Amortization period of intangible assets for tax purposes	15 years
eVestment
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived	$ 405			$ 405
eVestment \| Customer relationships
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived	$ 378
Discount rate used	9.30%
Estimated average useful life	14 years
eVestment \| Trade name
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived	$ 13
Discount rate used	9.20%
Estimated average useful life	8 years
eVestment \| Technology
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived	$ 14
Discount rate used	9.20%
Estimated average useful life	8 years
ISE
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets		$ 623			$ 623
ISE \| Customer relationships
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived		$ 148
Discount rate used		9.10%
Estimated average useful life		13 years
ISE \| Exchange registrations
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired intangible assets, indefinite lived		$ 467
Discount rate used		8.60%
ISE \| Trade name
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired intangible assets, indefinite lived		$ 8
Discount rate used		8.60%
Boardvantage
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived		$ 111				$ 111
Boardvantage \| Customer relationships
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived		$ 103
Discount rate used		15.50%
Estimated average useful life		14 years
Boardvantage \| Trade name
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived		$ 2
Discount rate used		15.00%
Estimated average useful life		1 year
Boardvantage \| Technology
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived		$ 6
Discount rate used		15.50%
Estimated average useful life		5 years
Marketwired
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived		$ 31					$ 31
Marketwired \| Customer relationships
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived		$ 29
Discount rate used		16.40%
Estimated average useful life		6 years
Marketwired \| Trade name
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived		$ 2
Discount rate used		15.80%
Estimated average useful life		2 years
Nasdaq Canada
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived		$ 76					$ 76
Nasdaq Canada \| Customer relationships
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived		$ 76
Discount rate used		10.30%
Estimated average useful life		17 years
DWA
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets			$ 141
DWA \| Customer relationships
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived			$ 29
Discount rate used			17.50%
Estimated average useful life			15 years
DWA \| Technology
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired Intangible Assets, Finite-lived			$ 4
Discount rate used			17.00%
Estimated average useful life			5 years
DWA \| Trade name
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Acquired intangible assets, indefinite lived			$ 108
Discount rate used			17.00%

Assets and Liabilities Held For Sale Assets and Liabilities Held For Sale (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Discontinued Operations and Disposal Groups [Abstract]
Impairment charge	$ 0
Receivables, net	27,000,000
Property and equipment, net	21,000,000
Goodwill (1)	202,000,000
Intangible assets, net	38,000,000
Other assets	9,000,000
Total assets held for sale	297,000,000	$ 0
Deferred tax liabilities	16,000,000
Other current liabilities	29,000,000
Total liabilities held for sale	$ 45,000,000	$ 0

Goodwill and Acquired Intangible Assets (Schedule of Changes in Goodwill) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2017
Goodwill [Roll Forward]
Balance at beginning of period		$ 6,027
Goodwill acquired		466
Measurement period adjustment		(7)
Foreign currency translation adjustment		302
Goodwill reclassified as held for sale		(202)
Balance at end of period		6,586
Market Services
Goodwill [Roll Forward]
Balance at beginning of period		3,390
Goodwill acquired		0
Measurement period adjustment		0
Foreign currency translation adjustment		156
Goodwill reclassified as held for sale		0
Balance at end of period		3,546
Corporate Services
Goodwill [Roll Forward]
Balance at beginning of period		674
Goodwill acquired		0
Measurement period adjustment	$ (7)	(7)
Foreign currency translation adjustment		25
Goodwill reclassified as held for sale		(202)
Balance at end of period		490
Information Services
Goodwill [Roll Forward]
Balance at beginning of period		1,806
Goodwill acquired		453
Measurement period adjustment		0
Foreign currency translation adjustment		103
Goodwill reclassified as held for sale		0
Balance at end of period		2,362
Market Technology
Goodwill [Roll Forward]
Balance at beginning of period		157
Goodwill acquired		13
Measurement period adjustment		0
Foreign currency translation adjustment		18
Goodwill reclassified as held for sale		0
Balance at end of period		$ 188

Goodwill and Acquired Intangible Assets (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Measurement period adjustment	$ 7,000,000
Goodwill expected to be deductible for tax purposes in future periods	864,000,000
Goodwill, impairment loss	0	$ 0	$ 0
Amortization expense for purchased finite-lived intangible assets	92,000,000	$ 82,000,000	$ 62,000,000
Future amortization expense, impact of foreign currency translation adjustments	$ (65,000,000)

Goodwill and Acquired Intangible Assets (Finite-Lived and Indefinite-Lived Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets
Gross Amount	$ 1,679	$ 1,279
Accumulated Amortization	(506)	(436)
Net Amount	1,173	843
Indefinite-Lived Intangible Assets
Indefinite-lived intangible assets	1,295	1,251
Gross Amount	2,974	2,530
Net Amount	2,468	2,094
Exchange and clearing registrations
Indefinite-Lived Intangible Assets
Indefinite-lived intangible assets	1,257	1,257
Trade names
Indefinite-Lived Intangible Assets
Indefinite-lived intangible assets	129	130
Licenses
Indefinite-Lived Intangible Assets
Indefinite-lived intangible assets	52	52
Foreign currency translation adjustment
Indefinite-Lived Intangible Assets
Indefinite-lived intangible assets	(143)	(188)
Technology
Finite-Lived Intangible Assets
Gross Amount	65	38
Accumulated Amortization	(22)	(24)
Net Amount	$ 43	$ 14
Weighted-Average Useful Life (in Years)	8 years	5 years
Customer relationships
Finite-Lived Intangible Assets
Gross Amount	$ 1,708	$ 1,394
Accumulated Amortization	(526)	(464)
Net Amount	$ 1,182	$ 930
Weighted-Average Useful Life (in Years)	18 years	18 years
Other
Finite-Lived Intangible Assets
Gross Amount	$ 17	$ 7
Accumulated Amortization	(4)	(6)
Net Amount	$ 13	$ 1
Weighted-Average Useful Life (in Years)	8 years	6 years
Foreign currency translation adjustment
Finite-Lived Intangible Assets
Gross Amount	$ (111)	$ (160)
Accumulated Amortization	46	58
Net Amount	$ (65)	$ (102)

Goodwill and Acquired Intangible Assets Intangible Assets Reclassified as Held for Sale (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 1,679	$ 1,279
Accumulated Amortization	(506)	(436)
Net Amount	1,173	843
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Amount	1,708	1,394
Accumulated Amortization	(526)	(464)
Net Amount	1,182	930
Other
Finite-Lived Intangible Assets [Line Items]
Gross Amount	17	7
Accumulated Amortization	(4)	(6)
Net Amount	13	$ 1
Disposal Group, Held-for-sale, Not Discontinued Operations
Finite-Lived Intangible Assets [Line Items]
Gross Amount	56
Accumulated Amortization	(18)
Net Amount	38
Disposal Group, Held-for-sale, Not Discontinued Operations \| Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Amount	54
Accumulated Amortization	(17)
Net Amount	37
Disposal Group, Held-for-sale, Not Discontinued Operations \| Other
Finite-Lived Intangible Assets [Line Items]
Gross Amount	2
Accumulated Amortization	(1)
Net Amount	$ 1

Goodwill and Acquired Intangible Assets (Estimated Future Amortization Expense) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2018	$ 114
2019	99
2020	99
2021	97
2022	94
2023 and thereafter	735
Total	$ 1,238

Goodwill and Acquired Intangible Assets Intangible Asset Impairment Charges (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Line Items]
Impairment of intangible assets, indefinite-lived (excluding goodwill)	$ 0
Rebranding of trade name
Goodwill [Line Items]
Impairment of intangible assets, indefinite-lived (excluding goodwill)		$ 578,000,000	$ 119,000,000
Asset impairment charge			$ 119,000,000
Trade name \| eSpeed
Goodwill [Line Items]
Impairment of intangible assets, indefinite-lived (excluding goodwill)		$ 578,000,000

Investments (Schedule of Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Trading securities	$ 221	$ 228
Available-for-sale investment securities	14	17
Equity method investments	131	124
Cost method investments	$ 152	$ 144

Investments (Narrative) (Details) - USD ($) $ / shares in Millions, $ in Millions	1 Months Ended		3 Months Ended	12 Months Ended
	Sep. 30, 2017	Mar. 31, 2015	Mar. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2016
Investments, Debt and Securities [Line Items]
Trading securities				$ 221	$ 228
Gross unrealized gain (loss)				0	0
Net income from unconsolidated investees				15	$ 2	$ 17
Wind down costs				$ 2
Borsa Istanbul Cost Method Investment
Investments, Debt and Securities [Line Items]
Ownership interest, cost method investments				5.00%	5.00%
Cost method investment, original amount				$ 75
LCH
Investments, Debt and Securities [Line Items]
Ownership interest, cost method investments				5.00%	5.00%
OCC
Investments, Debt and Securities [Line Items]
Net income from unconsolidated investees			$ 13
Committed equity contribution		$ 150	$ 150
Capital contribution		$ 30
Annual dividend from shareholders percentage		50.00%
Annual dividend (in dollars per share)	$ 5
Shares owned (in shares)				2
Annual dividend received	$ 10
OCC \| ISE
Investments, Debt and Securities [Line Items]
Additional ownership interest, equity method investments							20.00%
Ownership interest, equity method investments							40.00%
Order Machine
Investments, Debt and Securities [Line Items]
Asset impairment charge					$ 7
Foreign Government Debt Securities
Investments, Debt and Securities [Line Items]
Trading securities				$ 160	$ 172

Property and Equipment, net (Schedule of Property and Equipment, Net) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 905	$ 919
Less: accumulated depreciation and amortization	(505)	(557)
Total property and equipment, net	400	362	$ 323
Data processing equipment and software
Property, Plant and Equipment [Line Items]
Total property and equipment	626	665
Furniture, equipment and leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 279	$ 254

Property and Equipment, net (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Depreciation and amortization expense	$ 96	$ 88	$ 76
Asset impairment charges	$ 9	$ 8	$ 18

Deferred Revenue (Changes in Deferred Revenue) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Movement in Deferred Revenue [Roll Forward]
Beginning Balance	$ 333	$ 327
Additions	806	864
Revenue recognized	(823)	(849)
Translation adjustment	21	(9)
Deferred revenue reclassified as held for sale	(2)
Ending Balance	335	333
Initial Listing Revenues
Movement in Deferred Revenue [Roll Forward]
Beginning Balance	54	59
Additions	18	13
Revenue recognized	(17)	(18)
Translation adjustment	0	0
Deferred revenue reclassified as held for sale	0
Ending Balance	55	54
Listing of Additional Shares Revenues
Movement in Deferred Revenue [Roll Forward]
Beginning Balance	37	53
Additions	11	12
Revenue recognized	(22)	(28)
Translation adjustment	0	0
Deferred revenue reclassified as held for sale	0
Ending Balance	26	37
Annual Renewal and Other Revenues
Movement in Deferred Revenue [Roll Forward]
Beginning Balance	57	28
Additions	569	606
Revenue recognized	(544)	(576)
Translation adjustment	1	(1)
Deferred revenue reclassified as held for sale	(2)
Ending Balance	81	57
Market Technology Revenues
Movement in Deferred Revenue [Roll Forward]
Beginning Balance	185	187
Additions	208	233
Revenue recognized	(240)	(227)
Translation adjustment	20	(8)
Deferred revenue reclassified as held for sale	0
Ending Balance	$ 173	$ 185

Deferred Revenue (Estimated Deferred Revenue) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred Revenue Arrangement [Line Items]
2018	$ 189
2019	59
2020	49
2021	23
2022	7
2023 and thereafter	8
Deferred revenue estimated revenue to be recognized	335	$ 333	$ 327
Initial Listing Revenues
Deferred Revenue Arrangement [Line Items]
2018	17
2019	15
2020	11
2021	7
2022	4
2023 and thereafter	1
Deferred revenue estimated revenue to be recognized	55	54	59
Listing of Additional Shares Revenues
Deferred Revenue Arrangement [Line Items]
2018	13
2019	7
2020	5
2021	1
2022	0
2023 and thereafter	0
Deferred revenue estimated revenue to be recognized	26	37	53
Annual Renewal and Other Revenues
Deferred Revenue Arrangement [Line Items]
2018	79
2019	2
2020	0
2021	0
2022	0
2023 and thereafter	0
Deferred revenue estimated revenue to be recognized	81	57	28
Market Technology Revenues
Deferred Revenue Arrangement [Line Items]
2018	80
2019	35
2020	33
2021	15
2022	3
2023 and thereafter	7
Deferred revenue estimated revenue to be recognized	$ 173	$ 185	$ 187

Debt Obligations (Changes in Debt Obligations) (Details) - USD ($)	1 Months Ended		8 Months Ended	12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2017	Apr. 30, 2017	Mar. 31, 2016
Changes In Short-Term Debt Obligations [Roll Forward]
Short-term debt - commercial paper beginning balance				$ 0
Short-term debt - commercial paper ending balance			$ 480,000,000	480,000,000
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period				3,603,000,000
Additions				653,000,000
Payments, Accretion and Other				(529,000,000)
Long-term debt obligations at end of period			3,727,000,000	3,727,000,000
Changes In Debt Obligations [Roll Forward]
Total debt obligations at beginning of period				3,603,000,000
Additions				3,167,000,000
Payments, Accretion and Other				(2,563,000,000)
Total debt obligations at end of period			4,207,000,000	4,207,000,000
$400 million senior unsecured term loan facility due November 25, 2019 (average interest rate of 2.47% for the period January 1, 2017 through December 31, 2017)
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period				399,000,000
Additions				0
Payments, Accretion and Other		$ (300,000,000)		(299,000,000)
Long-term debt obligations at end of period			100,000,000	100,000,000
Credit facility, borrowing capacity			400,000,000	$ 400,000,000		$ 400,000,000
Interest rate during period				2.47%
Short-term debt - commercial paper
Changes In Short-Term Debt Obligations [Roll Forward]
Short-term debt - commercial paper beginning balance				$ 0
Additions				2,514,000,000
Payments, Accretion and Other				(2,034,000,000)
Short-term debt - commercial paper ending balance			480,000,000	480,000,000
Senior Notes \| 5.55% senior unsecured notes due January 15, 2020
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period				598,000,000
Additions				0
Payments, Accretion and Other				1,000,000
Long-term debt obligations at end of period			$ 599,000,000	$ 599,000,000
Stated rate			5.55%	5.55%
Senior Notes \| 5.25% senior unsecured notes repaid on May 26, 2017
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period				$ 369,000,000
Additions				0
Payments, Accretion and Other				(369,000,000)
Long-term debt obligations at end of period			$ 0	$ 0
Stated rate			5.25%	5.25%
Senior Notes \| 3.875% senior unsecured notes due June 7, 2021
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period				$ 625,000,000
Additions				0
Payments, Accretion and Other				91,000,000
Long-term debt obligations at end of period			$ 716,000,000	$ 716,000,000
Stated rate			3.875%	3.875%
Senior Notes \| 4.25% senior unsecured notes due June 1, 2024
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period				$ 495,000,000
Additions				0
Payments, Accretion and Other				1,000,000
Long-term debt obligations at end of period			$ 496,000,000	$ 496,000,000
Stated rate			4.25%	4.25%
Senior Notes \| 1.75% senior unsecured notes due May 19, 2023
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period				$ 622,000,000
Additions				0
Payments, Accretion and Other				90,000,000
Long-term debt obligations at end of period			$ 712,000,000	$ 712,000,000
Stated rate			1.75%	1.75%
Senior Notes \| 3.85% senior unsecured notes due June 30, 2026
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period				$ 495,000,000
Additions				0
Payments, Accretion and Other				1,000,000
Long-term debt obligations at end of period			$ 496,000,000	$ 496,000,000
Stated rate			3.85%	3.85%
Senior Notes \| Senior unsecured floating rate notes due March 22, 2019
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period				$ 0
Additions				498,000,000
Payments, Accretion and Other				0
Long-term debt obligations at end of period			$ 498,000,000	498,000,000
Senior Notes \| Senior unsecured floating rate notes due March 22, 2019 \| LIBOR
Changes in Long-Term Debt Obligations [Roll Forward]
Spread on variable rate	0.39%
Revolving Credit Facility \| $1 billion revolving credit commitment due April 25, 2022 (average interest rate of 2.66% for the period April 25, 2017 through December 31, 2017)
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period				0
Additions				155,000,000
Payments, Accretion and Other				(45,000,000)
Long-term debt obligations at end of period			110,000,000	110,000,000
Credit facility, borrowing capacity			$ 1,000,000,000	$ 1,000,000,000	$ 1,000,000,000
Interest rate during period			2.66%

Debt Obligations (Commercial Paper) (Details) - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Oct. 31, 2017	Jun. 30, 2017	Dec. 31, 2017
Short-term Debt [Line Items]
Repayment of debt			$ 529
Partial payment of outstanding commercial paper balance	$ 276
Short-term debt - commercial paper
Short-term Debt [Line Items]
Weighted average interest rate			1.70%
Short-term debt - commercial paper \| Minimum
Short-term Debt [Line Items]
Maturity period			12 days
Short-term debt - commercial paper \| Maximum
Short-term Debt [Line Items]
Maturity period			119 days
Short-term debt - commercial paper \| Weighted Average
Short-term Debt [Line Items]
Maturity period			22 days
$400 million senior unsecured term loan facility due November 25, 2019 (average interest rate of 2.47% for the period January 1, 2017 through December 31, 2017)
Short-term Debt [Line Items]
Repayment of debt		$ 300	$ 299

Debt Obligations (Early Extinguishment of 2018 Notes) (Details) - Senior Notes - 5.25% senior unsecured notes repaid on May 26, 2017 $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Stated rate	5.25%
Pre-tax charge	$ 9

Debt Obligations (3.875% Senior Unsecured Notes) (Details) - Senior Notes - 3.875% senior unsecured notes due June 7, 2021 $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Stated rate	3.875%
Foreign currency translation	$ 91
Maximum
Debt Instrument [Line Items]
Maximum interest rate on debt instrument	5.875%

Debt Obligations (4.25% Senior Unsecured Notes) (Details) - Senior Notes - 4.25% senior unsecured notes due June 1, 2024	Dec. 31, 2017
Debt Instrument [Line Items]
Stated rate	4.25%
Maximum
Debt Instrument [Line Items]
Maximum interest rate on debt instrument	6.25%

Debt Obligations (1.75% Senior Unsecured Notes) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Increase in carrying amount	$ (529)
Senior Notes \| 1.75% senior unsecured notes due May 19, 2023
Debt Instrument [Line Items]
Stated rate	1.75%
Increase in carrying amount	$ 90
Senior Notes \| 1.75% senior unsecured notes due May 19, 2023 \| Maximum
Debt Instrument [Line Items]
Maximum interest rate on debt instrument	3.75%

Debt Obligations (3.85% Senior Unsecured Notes) (Details) - Senior Notes - 3.85% senior unsecured notes due June 30, 2026	Dec. 31, 2017
Debt Instrument [Line Items]
Stated rate	3.85%
Maximum
Debt Instrument [Line Items]
Maximum interest rate on debt instrument	5.85%

Debt Obligations (2017 Credit Facility) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Balance		$ 3,727,000,000	$ 3,603,000,000
Short-term debt		480,000,000	0
Revolving Credit Facility \| $1 billion revolving credit commitment due April 25, 2022 (average interest rate of 2.66% for the period April 25, 2017 through December 31, 2017)
Debt Instrument [Line Items]
Credit facility, borrowing capacity	$ 1,000,000,000	1,000,000,000
Credit facility term	5 years
Balance		110,000,000	$ 0
Unamortized Debt Issuance Expense		5,000,000
Letter of credit		1,000,000
Credit facility, remaining residual borrowing capacity		404,000,000
Remaining amount available		885,000,000
Option to increase available aggregate amount		$ 500,000,000

Debt Obligations (2016 Credit Facility) (Details) - $400 million senior unsecured term loan facility due November 25, 2019 (average interest rate of 2.47% for the period January 1, 2017 through December 31, 2017) - USD ($)	1 Months Ended
	Jun. 30, 2017	Dec. 31, 2017	Mar. 31, 2016
Debt Instrument [Line Items]
Credit facility, borrowing capacity		$ 400,000,000	$ 400,000,000
Repayments of lines of credit	$ 300,000,000
Remaining amount outstanding		$ 100,000,000
Pre-tax charge related to the write-off of unamortized debt issuance costs	$ 1,000,000

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References + Details

Debt Obligations (2014 Credit Facility) (Details) - Revolving Credit Facility - $1 billion revolving credit commitment due April 25, 2022 (average interest rate of 2.40% for the period April 25, 2017 through June 30, 2017) - USD ($)	Dec. 31, 2017	Nov. 30, 2014
Debt Instrument [Line Items]
Credit facility, borrowing capacity		$ 750,000,000
Borrowings	$ 0

- Definition

+ References + Details

Income Taxes (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2012
Income Tax Disclosure [Line Items]
Undistributed earnings		$ 131
Income tax benefits primarily related to share-based compensation		40	$ 41	$ 34
Unrecognized tax benefits that would impact effective tax rate		45	48
Interest and penalties related to income tax		9	$ 8
Unrecognized tax benefits, decrease resulting from prior period tax positions	$ 8
Decrease to tax expense (benefit)		87
Foreign Tax Authority \| SE
Income Tax Disclosure [Line Items]
Tax expense (benefits) associated with foreign tax agency		$ 48			$ 56
Tax expense (benefits), per diluted share (in dollars per share)		$ 0.28
Foreign Tax Authority \| Minimum \| SE
Income Tax Disclosure [Line Items]
Quarterly recurring tax benefits		$ 1
Foreign Tax Authority \| Maximum \| SE
Income Tax Disclosure [Line Items]
Quarterly recurring tax benefits		$ 2

Income Taxes (Components of Income Tax Provision) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current income taxes:
Federal	$ 51	$ 37	$ 139
State	17	21	42
Foreign	68	106	36
Total current income taxes	136	164	217
Deferred income taxes:
Federal	(14)	(97)	(18)
State	24	(35)	(1)
Foreign	0	(4)	5
Total deferred income taxes	10	(136)	(14)
Total income tax provision	$ 146	$ 28	$ 203

Income Taxes (Reconciliation of Provision of Income Taxes) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal income tax provision at the statutory rate	35.00%	35.00%	35.00%
State income tax provision, net of federal effect	2.60%	(6.70%)	3.90%
Change in deferred taxes due to change in law	(9.90%)	(1.20%)	0.20%
Excess tax benefits related to employee share-based compensation	(4.00%)	(0.00%)	(0.00%)
Non-U.S. subsidiary earnings	(6.00%)	(7.30%)	(6.40%)
Tax credits and deductions	(1.00%)	(5.10%)	(0.80%)
Change in unrecognized tax benefits	(0.80%)	4.20%	0.30%
Other, net	0.70%	1.70%	0.00%
Actual income tax provision	16.60%	20.60%	32.20%

Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Deferred revenues	$ 25	$ 39
U.S. federal net operating loss	1	2
Foreign net operating loss	30	37
State net operating loss	4	1
Compensation and benefits	42	99
Foreign currency translation	292	528
Tax credits	7	7
Other	20	34
Gross deferred tax assets	421	747
Deferred tax liabilities:
Amortization of software development costs and depreciation	(47)	(63)
Amortization of acquired intangible assets	(510)	(596)
Investments	(26)	(37)
Other	(19)	(24)
Gross deferred tax liabilities	(602)	(720)
Net deferred tax assets (liabilities) before valuation allowance	(181)	27
Less: valuation allowance	(30)	(30)
Net deferred tax assets (liabilities)	$ (211)	$ (3)

Income Taxes (Net Operating Losses and Credits) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
U.S. Federal Tax credits	$ 7	$ 7
Federal Tax Authority
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforward, Subject to Expiration	1
U.S. Federal Tax credits	7
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforward, Subject to Expiration	4
Net Operating Loss Carryforward, Not Subject to Expiration	26
State and local jurisdiction
Operating Loss Carryforwards [Line Items]
Net Operating Loss Carryforward, Subject to Expiration	$ 4

Income Taxes (Domestic and Foreign Components of Income Before Income Tax Provision) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Domestic	$ 556	$ (155)	$ 393
Foreign	324	291	237
Income before income taxes	$ 880	$ 136	$ 630

Income Taxes (Reconciliation of Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Beginning balance	$ 48	$ 40
Additions as a result of tax positions taken in prior periods	2	9
Additions as a result of tax positions taken in the current period	5	3
Reductions related to settlements with taxing authorities	0	(4)
Reductions as a result of lapses of the applicable statute of limitations	(10)	0
Ending balance	$ 45	$ 48

Retirement Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Retirement Benefits [Abstract]
Employer contribution match, percent match	100.00%
Employer contribution match, percentage of employee contribution	6.00%
Defined contributions plan expense	$ 13	$ 11	$ 10
Cost or expenses included in compensation and benefit expense	21	23	22
Funded status of the plans	60	59	$ 64
Fair value of plan assets	79	74
Benefit obligations	139	$ 133
Accumulated other comprehensive loss	22
Unrecognized net loss	37
Income tax benefit due to pension plan	$ (15)

Retirement Plans Retirement Plans (Estimated Future Benefit Payments) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Defined Benefit Plan Disclosure [Line Items]
2018	$ 7
2019	12
2020	7
2021	7
2022	8
2023 through 2027	40
Total expected future benefit payments	81
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
2018	5
2019	5
2020	5
2021	5
2022	6
2023 through 2027	29
Total expected future benefit payments	55
Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
2018	2
2019	7
2020	2
2021	2
2022	2
2023 through 2027	10
Total expected future benefit payments	25
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
2018	0
2019	0
2020	0
2021	0
2022	0
2023 through 2027	1
Total expected future benefit payments	$ 1

Share-Based Compensation (Narrative) (Details) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 31, 2017 shares	Mar. 31, 2018 shares	Dec. 31, 2017 USD ($) program $ / shares peer_group shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) shares	Dec. 29, 2017 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance (in shares)			5,800,000
Stock option awards granted (in shares)			268,817
Net cash proceeds from the exercise of stock options \| $			$ 24	$ 41	$ 18
Stock options exercised in period (in shares)			1,102,830	1,219,820	682,054
Share Price (in dollars per share) \| $ / shares						$ 76.83
Stock options, exercisable (in shares)			302,563	1,400,000
Weighted average exercise price (in dollars per share) \| $ / shares			$ 23.55
Options exercisable, weighted average exercise price \| $ / shares			$ 23.55	$ 22.32
Total pre-tax intrinsic value of stock options exercised \| $			$ 54	$ 40	$ 17
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Discount from market price			15.00%	15.00%
Common stock shares reserved for future issuance (in shares)			2,100,000
Maximum percentage of shares purchased from annual compensation			10.00%
Discount given to employees			15.00%
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost \| $			$ 54
Weighted-average period unrecognized compensation cost is expected to be recognized, in years			1 year 9 months 15 days
Restricted stock \| Second Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Restricted stock \| Third Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Restricted stock \| Fourth Anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			50.00%
PSUs \| One Year Performance Share Unit Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost \| $			$ 9
Weighted-average period unrecognized compensation cost is expected to be recognized, in years			1 year 5 months
Performance period			1 year
Percentage of target amount granted, minimum			0.00%
Percentage of target amount granted, maximum			150.00%
Vesting period			3 years
PSUs \| Three Year Performance Share Unit Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost \| $			$ 21
Weighted-average period unrecognized compensation cost is expected to be recognized, in years			1 year 5 months
Performance period			3 years
Vesting period			3 years
Number of peer groups \| peer_group			2
Performance-based long-term incentive program weighted percentage			50.00%
Minimum payout			0.00%
Maximum payout			200.00%
Share Price (in dollars per share) \| $ / shares			$ 69.45	$ 66.36
PSUs \| Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of performance-based programs \| program			2
PSUs, Negative TSR \| Three Year Performance Share Unit Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum payout			100.00%
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option life			10 years
Stock option awards granted (in shares)				0
Employee Stock Option \| CEO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
Stock option awards granted (in shares)	268,817
Scenario, Forecast \| Subsequent Event \| PSUs \| One Year Performance Share Unit Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional units granted above target (in shares)		14,497
Scenario, Forecast \| Subsequent Event \| PSUs \| Three Year Performance Share Unit Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional units granted above target (in shares)		237,876

Share-Based Compensation (Summary of Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based compensation expense before income taxes	$ 70	$ 86	$ 68
Income tax benefit	(29)	(35)	(28)
Share-based compensation expense after income taxes	$ 41	$ 51	$ 40

Share-Based Compensation (Summary of Restricted Stock Activity) (Details) - Restricted stock - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Awards
Number of Awards, Unvested balances at beginning of period (in shares)	2,560,578	3,343,738	3,193,230
Number of Awards, Granted (in shares)	737,864	724,200	823,950
Number of Awards, Vested (in shares)	(1,102,823)	(1,238,980)	(370,998)
Number of Awards, Forfeited (in shares)	(207,119)	(268,380)	(302,444)
Number of Awards, Unvested balances at end of period (in shares)	1,988,500	2,560,578	3,343,738
Weighted-Average Grant Date Fair Value
Weighted-Average Grant Date Fair Value, Unvested balances at beginning of period (in dollars per share)	$ 45.92	$ 35.36	$ 30.99
Weighted-Average Grant Date Fair Value, Granted (in dollars per share)	67.48	62.91	49.26
Weighted-Average Grant Date Fair Value, Vested (in dollars per share)	38.56	27.91	29.90
Weighted-Average Grant Date Fair Value, Forfeited (in dollars per share)	52.29	43.29	34.34
Weighted-Average Grant Date Fair Value, Unvested balances at end of period (in dollars per share)	$ 57.34	$ 45.92	$ 35.36

Share-Based Compensation (Schedule of Weighted- Average Assumptions Used to Determine Weighted-Average Fair Values) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 29, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date share price (in dollars per share)			$ 76.83
PSUs \| Three Year Performance Share Unit Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average risk free interest rate	1.44%	0.84%
Expected volatility	19.20%	21.00%
Weighted-average grant date share price (in dollars per share)	$ 69.45	$ 66.36
Weighted-average fair value at grant date (in dollars per share)	$ 81.57	$ 93.25
Performance period	3 years

Share-Based Compensation (Summary of PSU Activity) (Details) - PSUs - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
One Year Performance Share Unit Program
Number of Awards
Number of Awards, Unvested balances at beginning of period (in shares)	378,766	423,967	558,040
Number of Awards, Granted (in shares)	197,075	242,642	206,199
Number of Awards, Vested (in shares)	(202,073)	(242,793)	(247,273)
Number of Awards, Forfeited (in shares)	(40,764)	(45,050)	(92,999)
Number of Awards, Unvested balances at end of period (in shares)	333,004	378,766	423,967
Weighted-Average Grant Date Fair Value
Weighted-Average Grant Date Fair Value, Unvested balances at beginning of period (in dollars per share)	$ 52.55	$ 41.34	$ 24.17
Weighted-Average Grant Date Fair Value, Granted (in dollars per share)	65.51	58.33	48.16
Weighted-Average Grant Date Fair Value, Vested (in dollars per share)	49.93	39.63	30.51
Weighted-Average Grant Date Fair Value, Forfeited (in dollars per share)	55.92	47.72	34.74
Weighted-Average Grant Date Fair Value, Unvested balances at end of period (in dollars per share)	$ 61.39	$ 52.55	$ 41.34
Three Year Performance Share Unit Program
Number of Awards
Number of Awards, Unvested balances at beginning of period (in shares)	1,314,668	1,439,718	1,654,567
Number of Awards, Granted (in shares)	803,712	761,501	649,626
Number of Awards, Vested (in shares)	(1,079,925)	(879,926)	(837,109)
Number of Awards, Forfeited (in shares)	(28,497)	(6,625)	(27,366)
Number of Awards, Unvested balances at end of period (in shares)	1,009,958	1,314,668	1,439,718
Weighted-Average Grant Date Fair Value
Weighted-Average Grant Date Fair Value, Unvested balances at beginning of period (in dollars per share)	$ 63.18	$ 49.41	$ 35.57
Weighted-Average Grant Date Fair Value, Granted (in dollars per share)	55.57	66.89	49.69
Weighted-Average Grant Date Fair Value, Vested (in dollars per share)	42.83	43.81	22.50
Weighted-Average Grant Date Fair Value, Forfeited (in dollars per share)	87.86	69.11	43.49
Weighted-Average Grant Date Fair Value, Unvested balances at end of period (in dollars per share)	$ 78.18	$ 63.18	$ 49.41

Share-Based Compensation (Summary of Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Number of Stock Options
Number of Stock Options, Outstanding at Beginning of period (in shares)	1,406,371	2,626,487	3,316,782
Number of Stock Options, Granted (in shares)	268,817
Number of Stock Options, Exercised (in shares)	(1,102,830)	(1,219,820)	(682,054)
Number of Stock Options, Forfeited (in shares)	(978)	(296)	(8,241)
Number of Stock Options, Outstanding at End of period (in shares)	571,380	1,406,371	2,626,487
Weighted-Average Exercise Price
Weighted-Average Exercise Price, Outstanding at Beginning of period (in dollars per share)	$ 22.32	$ 27.74	$ 27.56
Weighted-Average Exercise Price, Granted (in dollars per share)	66.68
Weighted-Average Exercise Price, Exercised (in dollars per share)	21.98	34.00	26.84
Weighted-Average Exercise Price, Forfeited (in dollars per share)	21.33	23.31	28.53
Weighted-Average Exercise Price, Outstanding at End of period (in dollars per share)	$ 43.84	$ 22.32	$ 27.74
Outstanding [Abstract]
Number of Stock Options (in shares)	571,380
Weighted-Average Remaining Contractual Term (in years)	5 years 4 months 25 days
Weighted-Average Exercise Price (in dollars per share)	$ 43.84
Aggregate Intrinsic Value	$ 19
Exercisable [Abstract]
Number Exercisable (in shares)	302,563
Weighted-Average Remaining Contractual Term (in years)	2 years 3 months 19 days
Weighted average exercise price (in dollars per share)	$ 23.55
Aggregate Intrinsic Value	$ 16
Exercise Price Range One
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	$ 17.36
Exercise price range, upper range limit (in dollars per share)	$ 19.99
Outstanding [Abstract]
Number of Stock Options (in shares)	94,265
Weighted-Average Remaining Contractual Term (in years)	2 years 1 month 21 days
Weighted-Average Exercise Price (in dollars per share)	$ 19.73
Aggregate Intrinsic Value	$ 5
Exercisable [Abstract]
Number Exercisable (in shares)	94,265
Weighted-Average Remaining Contractual Term (in years)	2 years 1 month 21 days
Weighted average exercise price (in dollars per share)	$ 19.73
Aggregate Intrinsic Value	$ 5
Exercise Price Range Two
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	$ 20
Exercise price range, upper range limit (in dollars per share)	$ 25.75
Outstanding [Abstract]
Number of Stock Options (in shares)	206,980
Weighted-Average Remaining Contractual Term (in years)	2 years 4 months 20 days
Weighted-Average Exercise Price (in dollars per share)	$ 25.20
Aggregate Intrinsic Value	$ 11
Exercisable [Abstract]
Number Exercisable (in shares)	206,980
Weighted-Average Remaining Contractual Term (in years)	2 years 4 months 20 days
Weighted average exercise price (in dollars per share)	$ 25.20
Aggregate Intrinsic Value	$ 11
Exercise Price Range Three
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	$ 25.76
Exercise price range, upper range limit (in dollars per share)	$ 66.68
Outstanding [Abstract]
Number of Stock Options (in shares)	270,135
Weighted-Average Remaining Contractual Term (in years)	8 years 10 months 3 days
Weighted-Average Exercise Price (in dollars per share)	$ 66.53
Aggregate Intrinsic Value	$ 3
Exercisable [Abstract]
Number Exercisable (in shares)	1,318
Weighted-Average Remaining Contractual Term (in years)	5 months 24 days
Weighted average exercise price (in dollars per share)	$ 36.40
Aggregate Intrinsic Value	$ 0

Share-Based Compensation Summary of Employee Stock Purchase Plan (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 70	$ 86	$ 68
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares purchased by employees	235,859	233,464	247,444
Weighted-average price of shares purchased (in dollars per share)	$ 58.26	$ 50.39	$ 40.95
Compensation expense	$ 3	$ 4	$ 4

Nasdaq Stockholders' Equity (Narrative) (Details)					1 Months Ended		12 Months Ended
Nasdaq Stockholders' Equity (Narrative) (Details)	Jun. 30, 2017 USD ($)	Apr. 25, 2017 $ / shares	Mar. 31, 2017 USD ($)	Jan. 30, 2017 $ / shares	Jan. 31, 2018 USD ($) $ / shares shares	Apr. 30, 2017 $ / shares	Dec. 31, 2017 USD ($) vote $ / shares shares	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares	Mar. 31, 2016 USD ($)	Dec. 31, 2014 USD ($)
Stockholders Equity [Line Items]
Common stock, shares authorized (in shares)							300,000,000	300,000,000
Common stock, shares issued (in shares)							172,373,432	170,501,186
Common stock, shares outstanding (in shares)							167,441,030	166,579,468
Common stock (in votes per share) \| vote							1
Common stock holder voting rights, maximum percentage of the then-outstanding shares of Nasdaq common stock							5.00%
Common stock in treasury (in shares)							4,932,402	3,921,718
Share repurchase program, authorized amount \| $										$ 370,000,000	$ 500,000,000
Remaining authorized share repurchase amounts under repurchase program \| $							$ 226,000,000
Number of shares of common stock repurchased (in shares)							2,843,519	1,547,778
Preferred stock, shares authorized (in shares)							30,000,000
Preferred stock par value (in dollars per share) \| $ / shares							$ 0.01
Amount paid \| $							$ 243,000,000	$ 200,000,000	$ 149,000,000
Cash dividends declared per common share (in dollars per share) \| $ / shares							$ 1.46	$ 1.21	$ 0.9
Subsequent Event
Stockholders Equity [Line Items]
Share repurchase program, authorized amount \| $					$ 726,000,000
Number of additional shares authorized to be repurchased					500,000,000
Prior Quarterly Cash Dividend
Stockholders Equity [Line Items]
Amount paid \| $			$ 53,000,000
Cash dividends declared per common share (in dollars per share) \| $ / shares				$ 0.32
April 2017
Stockholders Equity [Line Items]
Amount paid \| $	$ 63,000,000
Cash dividends declared per common share (in dollars per share) \| $ / shares		$ 0.38				$ 0.38
Percent increase over prior quarter dividend						19.00%
October 2017 \| Subsequent Event
Stockholders Equity [Line Items]
Amount paid \| $					$ 64,000,000
Cash dividends declared per common share (in dollars per share) \| $ / shares					$ 0.38
Other Repurchases of Common Stock
Stockholders Equity [Line Items]
Number of shares of common stock repurchased (in shares)							1,008,882
Series A Preferred Stock
Stockholders Equity [Line Items]
Preferred stock, series A convertible preferred stock, shares issued (in shares)							0	0
Preferred stock, series A convertible preferred stock, shares outstanding (in shares)							0	0

Nasdaq Stockholders' Equity (Common Stock in Treasury) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Equity [Abstract]
Number of shares of common stock repurchased (in shares)	2,843,519	1,547,778
Average per share price of repurchased stock (in dollars per share)	$ 71.56	$ 64.42
Total purchase price (in millions)	$ 203	$ 100	$ 377

Nasdaq Stockholders' Equity (Schedule of Dividends Declared) (Details) - USD ($) $ / shares in Units, $ in Millions									1 Months Ended	12 Months Ended
	Dec. 29, 2017	Oct. 24, 2017	Sep. 29, 2017	Jul. 25, 2017	Jun. 30, 2017	Apr. 25, 2017	Mar. 31, 2017	Jan. 30, 2017	Apr. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Dividends Payable [Line Items]
Dividend per common share (in dollars per share)										$ 1.46	$ 1.21	$ 0.9
Total Amount Paid										$ 243	$ 200	$ 149
January 30, 2017
Dividends Payable [Line Items]
Dividend per common share (in dollars per share)								$ 0.32
Total Amount Paid							$ 53
4/25/2017
Dividends Payable [Line Items]
Dividend per common share (in dollars per share)						$ 0.38			$ 0.38
Total Amount Paid					$ 63
7/25/2017
Dividends Payable [Line Items]
Dividend per common share (in dollars per share)				$ 0.38
Total Amount Paid			$ 64
October 24, 2017
Dividends Payable [Line Items]
Dividend per common share (in dollars per share)		$ 0.38
Total Amount Paid	$ 63

Nasdaq Stockholders' Equity Nasdaq Stockholders' Equity (Components of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gross balance	$ (1,305)	$ (1,516)
Income taxes	443	537
Net balance	(862)	(979)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gross balance	(1,268)	(1,481)
Income taxes	428	523
Net balance	(840)	(958)
Employee Benefit Plan Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Gross balance	(37)	(35)
Income taxes	15	14
Net balance	$ (22)	$ (21)

Earnings Per Share (Narrative) (Details) - shares	12 Months Ended
Earnings Per Share (Narrative) (Details) - shares	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Stock options to purchase shares (in shares)	571,380	1,406,371	2,626,487	3,316,782
Diluted shares outstanding (in shares)	2,861,892	3,258,136	3,638,981
Common stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Stock options to purchase shares (in shares)	571,380	1,406,371	2,626,487
Diluted shares outstanding (in shares)	302,563
Restricted stock and PSU's
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Stock options to purchase shares (in shares)	3,331,462	4,254,012	5,207,423
Diluted shares outstanding (in shares)	2,978,856	3,663,919	4,842,383

Earnings Per Share (Summary of Computation of Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net income attributable to common shareholders	$ 734	$ 108	$ 428
Weighted-average common shares outstanding for basic earnings per share (in shares)	166,364,299	165,182,290	167,285,450
Weighted-average effect of dilutive securities:
Employee equity awards (in shares)	2,861,892	3,258,136	3,638,981
Contingent issuance of common stock (in shares)	358,840	360,571	358,840
Weighted-average common shares outstanding for diluted earnings per share (in shares)	169,585,031	168,800,997	171,283,271
Basic earnings per share (in dollars per share)	$ 4.41	$ 0.65	$ 2.56
Diluted earnings per share (in dollars per share)	$ 4.33	$ 0.64	$ 2.50

Fair Value of Financial Instruments (Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial investments, at fair value	$ 235	$ 245
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial investments, at fair value	235	245
Default fund and margin deposit investments	2,129	1,900
Total	2,364	2,145
Fair Value, Measurements, Recurring \| Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial investments, at fair value	135	151
Default fund and margin deposit investments	371	614
Total	506	765
Fair Value, Measurements, Recurring \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial investments, at fair value	100	94
Default fund and margin deposit investments	1,758	1,286
Total	1,858	1,380
Fair Value, Measurements, Recurring \| Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial investments, at fair value	0	0
Default fund and margin deposit investments	0	0
Total	$ 0	$ 0

Fair Value of Financial Instruments (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	$ 221,000,000	$ 228,000,000
Default funds and margin deposits	3,988,000,000	3,301,000,000
Highly rated government debt securities	1,909,000,000	1,763,000,000
Transfers from between level 1 and level 2	0	0
Non-financial assets measured at fair value on non-recurring basis	0	0
Fair Value, Measurements, Nonrecurring \| Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of debt utilizing discounted cash flow analyses	4,400,000,000	3,800,000,000
Reverse Repurchase Agreements
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Default funds and margin deposits	220,000,000	137,000,000
Foreign Government Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	$ 160,000,000	$ 172,000,000

Clearing Operations (Narrative) (Details) $ in Millions	12 Months Ended
Clearing Operations (Narrative) (Details) $ in Millions	Dec. 31, 2017 USD ($) contract fund	Dec. 31, 2016 USD ($) contract
Clearing Operations [Line Items]
Number of member sponsored default funds \| fund	4
Default funds and margin deposits	$ 3,988	$ 3,301
Default fund cash contributions invested in highly rated government debt securities	1,909	1,763
Default fund contributions	490
Committed capital	235	245
Liability Waterfall
Clearing Operations [Line Items]
Junior capital, cash deposits and pledged assets	18
Senior capital, cash deposits and pledged assets	24
Utilize as capital resources
Clearing Operations [Line Items]
Default fund contributions	454
Utilize as member posted surplus balance
Clearing Operations [Line Items]
Default fund contributions	36
Reverse Repurchase Agreements
Clearing Operations [Line Items]
Default funds and margin deposits	220	137
Nasdaq Clearing
Clearing Operations [Line Items]
Default fund cash contributions invested in highly rated government debt securities	1,909
Committed capital	114
Outstanding contract value of resale and repurchase agreements	$ 2,300	$ 1,900
Total number of derivative contracts cleared \| contract	8,534,986	7,941,666
Power of assessment of the clearing member's contribution to the financial markets and commodities markets default funds	100.00%
Nasdaq Clearing \| Reverse Repurchase Agreements
Clearing Operations [Line Items]
Default funds and margin deposits	$ 220

Clearing Operations (Schedule of Clearing Member Default Fund Contributions And Margin Deposits) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Clearing Operations [Line Items]
Default fund contributions	$ 490
Margin deposits	7,675
Total	8,165
Cash Contributions
Clearing Operations [Line Items]
Default fund contributions	360
Margin deposits	3,628
Total	3,988
Non-Cash Contributions
Clearing Operations [Line Items]
Default fund contributions	130
Margin deposits	4,047
Total	$ 4,177

Clearing Operations (Schedule of Derivative Contracts Outstanding) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) TWh contract	Dec. 31, 2016 TWh contract
Clearing Operations [Line Items]
Market value of derivative contracts \| $	$ 1,496
Total number of cleared contracts \| contract	94,152,671	97,302,481
Total volume in cleared power, in Terawatt hours (TWh) \| TWh	1,199	1,658
Commodity and seafood options, futures and forwards
Clearing Operations [Line Items]
Market value of derivative contracts \| $	$ 524
Total number of cleared contracts \| contract	2,824,188	3,530,746
Fixed-income options and futures
Clearing Operations [Line Items]
Market value of derivative contracts \| $	$ 729
Total number of cleared contracts \| contract	20,376,383	14,639,065
Stock options and futures
Clearing Operations [Line Items]
Market value of derivative contracts \| $	$ 132
Total number of cleared contracts \| contract	26,023,816	28,496,143
Index options and futures
Clearing Operations [Line Items]
Market value of derivative contracts \| $	$ 111
Total number of cleared contracts \| contract	44,928,284	50,636,527

Leases - (Future Minimum Lease Payments) (Details) $ in Millions	Dec. 31, 2017 USD ($)
Gross Lease Commitments
Operating Leased Assets [Line Items]
2018	$ 90
2019	76
2020	70
2021	57
2022	51
Thereafter	113
Total future minimum lease payments	457
Sublease Income
Operating Leased Assets [Line Items]
2018	3
2019	3
2020	3
2021	3
2022	3
Thereafter	3
Total future minimum lease payments	18
Net Lease Commitments
Operating Leased Assets [Line Items]
2018	87
2019	73
2020	67
2021	54
2022	48
Thereafter	110
Total future minimum lease payments	$ 439

Commitments, Contingencies and Guarantees (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Line Items]
Financial guarantees obtained	$ 14,000,000	$ 13,000,000
Margin deposits contributed to Cantor Fitzgerald	$ 19,000,000
eSpeed
Commitments and Contingencies Disclosure [Line Items]
Contingent future issuance of common stock (in shares)	992,247
Revenue required to trigger annual issuance of Nasdaq common stock	$ 25,000,000
Property Lease Guarantee
Commitments and Contingencies Disclosure [Line Items]
Other guarantees	3,000,000	3,000,000
Escrow Agreement
Commitments and Contingencies Disclosure [Line Items]
Contingency, accrual	18,000,000
Escrow Agreement \| Other current liabilities
Commitments and Contingencies Disclosure [Line Items]
Contingency, accrual	14,000,000
Escrow Agreement \| Other non-current liabilities
Commitments and Contingencies Disclosure [Line Items]
Contingency, accrual	4,000,000
Clearinghouse Credit Facilities
Commitments and Contingencies Disclosure [Line Items]
Credit facility, available liquidity	$ 187,000,000	$ 170,000,000

Business Segments (Schedule of Operating Segments) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting [Abstract]
Number of business segments \| segment	4
Segment Reporting Information [Line Items]
Total revenues	$ 3,965	$ 3,705	$ 3,403
Transaction-based expenses	(1,537)	(1,428)	(1,313)
Revenues less transaction-based expenses	2,428	2,277	2,090
Depreciation and amortization	188	170	138
Operating income (loss)	999	839	720
Total assets	15,786	14,150	11,861
Purchase of property and equipment	144	134	133
Operating Segments \| Market Services
Segment Reporting Information [Line Items]
Total revenues	2,418	2,255	2,084
Transaction-based expenses	(1,537)	(1,428)	(1,313)
Revenues less transaction-based expenses	881	827	771
Depreciation and amortization	95	87	64
Operating income (loss)	481	450	413
Total assets	9,471	8,626	6,906
Purchase of property and equipment	59	62	53
Operating Segments \| Corporate Services
Segment Reporting Information [Line Items]
Total revenues	656	635	562
Transaction-based expenses	0	0	0
Revenues less transaction-based expenses	656	635	562
Depreciation and amortization	49	47	42
Operating income (loss)	184	158	140
Total assets	866	1,263	576
Purchase of property and equipment	41	37	38
Operating Segments \| Information Services
Segment Reporting Information [Line Items]
Total revenues	588	540	512
Transaction-based expenses	0	0	0
Revenues less transaction-based expenses	588	540	512
Depreciation and amortization	25	18	14
Operating income (loss)	418	383	365
Total assets	3,420	2,439	2,456
Purchase of property and equipment	10	8	11
Operating Segments \| Market Technology
Segment Reporting Information [Line Items]
Total revenues	303	275	245
Transaction-based expenses	0	0	0
Revenues less transaction-based expenses	303	275	245
Depreciation and amortization	19	18	18
Operating income (loss)	65	69	58
Total assets	627	559	752
Purchase of property and equipment	34	27	31
Corporate Items
Segment Reporting Information [Line Items]
Operating income (loss)	(149)	(221)	(256)
Total assets	$ 1,402	$ 1,263	$ 1,171

Business Segments (Corporate Items) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Amortization expense of acquired intangible assets	$ 92	$ 82	$ 62
Merger and strategic initiatives	44	76	10
Restructuring charges	0	41	172
Loss on extinguishment of debt	(9)	0	0
Regulatory	33	35	27
Executive compensation	675	664	590
Total	(999)	(839)	(720)
Corporate Items
Segment Reporting Information [Line Items]
Amortization expense of acquired intangible assets	92	82	62
Merger and strategic initiatives	44	76	10
Restructuring charges	0	41	172
Loss on extinguishment of debt	10	0	0
Regulatory	1	6	0
Sublease loss reserve	2	(1)	0
Reversal of VAT refund receivables	0	0	12
Other	0	5	0
Total	149	221	256
Executive Officer \| Corporate Items
Segment Reporting Information [Line Items]
Executive compensation	$ 0	$ 12	$ 0

Business Segments Business Segments - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Increase decrease in total assets	$ 1,636,000,000	$ 2,289,000,000
Impairment of intangible assets, indefinite-lived (excluding goodwill)	$ 0
Trade name \| eSpeed
Segment Reporting Information [Line Items]
Impairment of intangible assets, indefinite-lived (excluding goodwill)		$ 578,000,000

Business Segments Business Segments (Geographic Data) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 3,965	$ 3,705	$ 3,403
Property and equipment, net	400	362	323
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	3,062	2,659	2,408
Property and equipment, net	247	244	217
All Other Countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	903	1,046	995
Property and equipment, net	$ 153	$ 118	$ 106

Subsequent Events (Details) - USD ($)	Jan. 31, 2018	Mar. 31, 2016	Dec. 31, 2014
Subsequent Event [Line Items]
Share repurchase program, authorized amount		$ 370,000,000	$ 500,000,000
Subsequent Event
Subsequent Event [Line Items]
Number of additional shares authorized to be repurchased	500,000,000
Share repurchase program, authorized amount	$ 726,000,000
Disposal Group, Not Discontinued Operations \| Public Relations Solutions \| Subsequent Event
Subsequent Event [Line Items]
Proceeds from sale of business segment	$ 335,000,000

Debt Obligations (Senior Unsecured Notes) (Details)	12 Months Ended
Debt Obligations (Senior Unsecured Notes) (Details)	Dec. 31, 2017
Senior Notes \| Senior Notes Excluding 2020 Notes
Debt Instrument [Line Items]
Aggregate principal amount purchased plus accrued and unpaid interest	101.00%

Leases - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Leases - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Leases [Abstract]
Operating sublease income	$ 3	$ 4	$ 5
Rent expense for operating leases	$ 83	$ 78	$ 88