Nasdaq (NDAQ) 10-Q 5 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 26, 2019
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	001-38855
Entity Registrant Name	Nasdaq, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	52-1165937
Entity Address, Address Line One	151 W. 42nd Street,
Entity Address, City or Town	New York,
Entity Address, State or Province	NY
Entity Address, Postal Zip Code	10036
City Area Code	212
Local Phone Number	401 8700
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		164,687,750
Entity Central Index Key	0001120193
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Amendment Flag	false
Common Stock, $.01 par value per share
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	NDAQ
Security Exchange Name	NASDAQ
1.75% Senior Notes Due 2029
Entity Information [Line Items]
Title of 12(b) Security	1.75% Senior Notes due 2029
Trading Symbol	NDAQ29
Security Exchange Name	NASDAQ
3.875% Senior Notes Due 2021
Entity Information [Line Items]
Title of 12(b) Security	3.875% Senior Notes due 2021
Trading Symbol	NDAQ21
Security Exchange Name	NASDAQ
1.75% Senior Note Due 2023
Entity Information [Line Items]
Title of 12(b) Security	1.750% Senior Notes due 2023
Trading Symbol	NDAQ23
Security Exchange Name	NASDAQ

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 333	$ 545
Restricted cash	30	41
Financial investments, at fair value	259	268
Receivables, net	415	384
Default funds and margin deposits	3,161	4,742
Other current assets	165	390
Total current assets	4,363	6,370
Property and equipment, net	390	376
Goodwill	6,382	6,363
Intangible assets, net	2,304	2,300
Operating lease assets	365
Other non-current assets	328	291
Total assets	14,132	15,700
Current liabilities:
Accounts payable and accrued expenses	149	198
Section 31 fees payable to SEC	170	109
Accrued personnel costs	119	199
Deferred revenue	333	194
Other current liabilities	132	253
Default funds and margin deposits	3,161	4,742
Short-term debt	467	875
Total current liabilities	4,531	6,570
Long-term debt	3,022	2,956
Deferred tax liabilities, net	510	501
Operating lease liabilities	343
Other non-current liabilities	175	224
Total liabilities	8,581	10,251
Commitments and contingencies
Nasdaq stockholders’ equity:
Common stock, $0.01 par value, 300,000,000 shares authorized, shares issued: 171,288,122 at June 30, 2019 and 170,709,425 at December 31, 2018; shares outstanding: 165,389,235 at June 30, 2019 and 165,165,104 at December 31, 2018	2	2
Additional paid-in capital	2,713	2,716
Common stock in treasury, at cost: 5,898,887 shares at June 30, 2019 and 5,544,321 shares at December 31, 2018	(327)	(297)
Accumulated other comprehensive loss	(1,666)	(1,530)
Retained earnings	4,829	4,558
Total Nasdaq stockholders’ equity	5,551	5,449
Total liabilities and equity	$ 14,132	$ 15,700

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
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)	171,288,122	170,709,425
Common stock, shares outstanding (in shares)	165,389,235	165,165,104
Common stock in treasury (in shares)	5,898,887	5,544,321

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues:
Total revenues	$ 1,061	$ 1,027	$ 2,100	$ 2,178
Transaction-based expenses:
Transaction rebates	(331)	(308)	(661)	(657)
Brokerage, clearance and exchange fees	(107)	(104)	(182)	(240)
Revenues less transaction-based expenses	623	615	1,257	1,281
Operating expenses:
Compensation and benefits	169	173	344	370
Professional and contract services	30	34	68	71
Computer operations and data communications	33	30	65	62
Occupancy	24	23	48	49
General, administrative and other	40	25	56	47
Marketing and advertising	10	10	20	19
Depreciation and amortization	48	53	96	106
Regulatory	8	8	15	16
Merger and strategic initiatives	5	(10)	14	0
Total operating expenses	367	346	726	740
Operating income	256	269	531	541
Interest income	3	2	6	5
Interest expense	(31)	(37)	(68)	(75)
Net gain on divestiture of businesses	0	41	27	41
Other investment income	1	8	1	8
Net income from unconsolidated investees	10	5	55	7
Income before income taxes	239	288	552	527
Income tax provision	65	126	131	188
Net income attributable to Nasdaq	$ 174	$ 162	$ 421	$ 339
Per share information:
Basic earnings per share (in dollars per share)	$ 1.05	$ 0.98	$ 2.54	$ 2.04
Diluted earnings per share (in dollars per share)	1.04	0.97	2.52	2.02
Cash dividends declared per common share (in dollars per share)	$ 0.47	$ 0	$ 0.91	$ 0.82
Market Services
Revenues:
Total revenues	$ 665	$ 649	$ 1,304	$ 1,384
Corporate Services
Revenues:
Total revenues	123	120	243	243
Information Services
Revenues:
Total revenues	194	175	387	348
Market Technology
Revenues:
Total revenues	79	66	156	126
Other revenues
Revenues:
Total revenues	$ 0	17	10	77
Transaction-based expenses:
Revenues less transaction-based expenses		$ 17	$ 10	$ 77

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income attributable to Nasdaq		$ 174	$ 162	$ 421	$ 339
Other comprehensive loss:
Foreign currency translation losses		(29)	(185)	(135)	(261)
Income tax benefit (expense)	[1]	8	54	(1)	(61)
Foreign currency translation, net		(21)	(131)	(136)	(322)
Employee benefit plan income tax expense	[1]	0	0	0	(7)
Total other comprehensive loss, net of tax		(21)	(131)	(136)	(329)
Comprehensive income attributable to Nasdaq		$ 153	$ 31	$ 285	$ 10
[1]	Includes a reclassification of the stranded tax effects, for the six months ended June 30, 2018, related to the Tax Cuts and Jobs Act. See “Tax Cuts and Jobs Act,” of Note 17, “Income Taxes,” for further discussion.

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Millions		Total	Common stock	Additional paid-in capital	Common stock in Treasury	Accumulated Other Comprehensive Loss		Retained Earnings
Beginning balance (in shares) at Dec. 31, 2017			167,441,030
Beginning balance at Dec. 31, 2017			$ 2	$ 3,024	$ (247)	$ (862)		$ 3,963
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchase program (in shares)				(3,929,520)
Share repurchase program		$ (340)		$ (340)
Share-based compensation (in shares)				1,308,900
Share-based compensation				$ 33
Stock option exercises, net (in shares)		88,000		88,000
Stock option exercises, net				$ 2
Other employee stock activity (in shares)				127,363	(532,369)
Other employee stock activity				$ (7)	$ (43)
Other comprehensive loss						(329)	[1]	142
Net income								339
Cash dividends declared per common share								(135)
Ending balance (in shares) at Jun. 30, 2018		164,503,404
Ending balance at Jun. 30, 2018		$ 5,542		2,712	(290)	(1,191)		4,309
Beginning balance (in shares) at Mar. 31, 2018			166,946,592
Beginning balance at Mar. 31, 2018			$ 2	$ 2,926	$ (289)	(1,060)		4,147
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchase program (in shares)				(2,670,574)
Share repurchase program				$ (241)
Share-based compensation (in shares)				58,887
Share-based compensation				$ 18
Stock option exercises, net (in shares)		53,805		53,805
Stock option exercises, net				$ 1
Other employee stock activity (in shares)				127,349	(12,655)
Other employee stock activity				$ 8	$ (1)
Other comprehensive loss	[1]					(131)
Net income								162
Cash dividends declared per common share								0
Ending balance (in shares) at Jun. 30, 2018		164,503,404
Ending balance at Jun. 30, 2018		$ 5,542		2,712	(290)	(1,191)		4,309
Beginning balance (in shares) at Dec. 31, 2018			165,165,104
Beginning balance at Dec. 31, 2018			$ 2	$ 2,716	$ (297)	(1,530)		4,558
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchase program (in shares)				(538,449)
Share repurchase program		$ (50)		$ (50)
Share-based compensation (in shares)				917,010
Share-based compensation				$ 36
Stock option exercises, net (in shares)		53,408		53,408
Stock option exercises, net				$ 1
Other employee stock activity (in shares)				146,728	(354,566)
Other employee stock activity				$ 10	$ (30)
Other comprehensive loss	[1]					(136)
Net income								421
Cash dividends declared per common share		$ (150)						(150)
Ending balance (in shares) at Jun. 30, 2019		165,389,235
Ending balance at Jun. 30, 2019		$ 5,551		2,713	(327)	(1,666)		4,829
Beginning balance (in shares) at Mar. 31, 2019			165,701,483
Beginning balance at Mar. 31, 2019			$ 2	$ 2,732	$ (327)	(1,645)		4,732
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares repurchase program (in shares)				(538,449)
Share repurchase program				$ (50)
Share-based compensation (in shares)				42,606
Share-based compensation				$ 20
Stock option exercises, net (in shares)		44,742		44,742
Stock option exercises, net				$ 1
Other employee stock activity (in shares)				146,241	(7,388)
Other employee stock activity				$ 10	$ 0
Other comprehensive loss	[1]					(21)
Net income								174
Cash dividends declared per common share								(77)
Ending balance (in shares) at Jun. 30, 2019		165,389,235
Ending balance at Jun. 30, 2019		$ 5,551		$ 2,713	$ (327)	$ (1,666)		$ 4,829
[1]	Includes a reclassification of the stranded tax effects, for the six months ended June 30, 2018, related to the Tax Cuts and Jobs Act. See “Tax Cuts and Jobs Act,” of Note 17, “Income Taxes,” for further discussion.

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 174	$ 162	$ 421	$ 339
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	48	53	96	106
Share-based compensation			36	33
Deferred income taxes			(1)	(36)
Reversal of certain Swedish tax benefits			0	41
Net gain on divestiture of businesses	0	(41)	(27)	(41)
Net income from unconsolidated investees	(10)	(5)	(55)	(7)
Other reconciling items included in net income			15	9
Net change in operating assets and liabilities, net of effects of divestiture and acquisitions:
Receivables, net			(20)	(52)
Other assets			(186)	40
Accounts payable and accrued expenses			(37)	11
Section 31 fees payable to SEC			61	97
Accrued personnel costs			(78)	(53)
Deferred revenue			112	131
Other liabilities			186	36
Net cash provided by operating activities			523	654
Cash flows from investing activities:
Purchases of securities			(311)	(250)
Proceeds from sales and redemptions of securities			309	158
Proceeds from divestiture of businesses			108	294
Acquisition of business, net of cash and cash equivalents acquired			(193)	0
Purchases of property and equipment			(63)	(45)
Other investing activities			(13)	(6)
Net cash provided by (used in) investing activities			(163)	151
Cash flows from financing activities:
Proceeds from (repayments of) commercial paper, net			192	(212)
Repayments of debt obligations			(1,215)	(115)
Payment of debt extinguishment cost			(11)	0
Proceeds from issuances of long-term debt, net of issuance costs			680	0
Repurchases of common stock			(50)	(340)
Dividends paid			(150)	(135)
Proceeds received from employee stock activity			11	10
Payments related to employee shares withheld for taxes			(30)	(43)
Net cash used in financing activities			(573)	(835)
Effect of exchange rate changes on cash and cash equivalents and restricted cash			(10)	(13)
Net decrease in cash and cash equivalents and restricted cash			(223)	(43)
Cash and cash equivalents and restricted cash at beginning of period			586	399	$ 399
Cash and cash equivalents and restricted cash at end of period	$ 363	$ 356	363	356	$ 586
Cash paid for:
Interest			85	89
Income taxes, net of refund			$ 129	$ 99

Organization and Nature of Oper

Organization and Nature of Operations	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization and Nature of Operations	Organization and Nature of Operations Nasdaq is a leading global provider of trading, clearing, exchange technology, listing, information and public company services. Through its diverse portfolio of solutions, Nasdaq enables customers to plan, optimize and execute their business vision with confidence, using proven technologies that provide transparency and insight for navigating today's global capital markets. As the creator of the world's first electronic stock market, its technology powers more than 100 marketplaces in 50 countries. Nasdaq is home to approximately 4,000 total listings with a market value of approximately $14 trillion . 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 a Canadian exchange for the trading of certain 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, as Nasdaq Nordic. 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 European commodity-related products and services. Nasdaq Commodities’ offerings include derivatives in oil, power, natural gas and carbon emission markets, seafood, 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, and connectivity to various data feeds. We also provide data center services, including co-location to market participants, whereby we offer firms cabinet space and power to house their own servers and other equipment within our data centers. Our broker services operations offer technology and customized securities administration solutions to financial participants in the Nordic market. In March 2019, we entered into an agreement to sell Nordic Fund Market, an electronic mutual fund service which is a small part of our Broker Services business. The closing of this transaction, which is subject to regulatory approvals and customary closing conditions, is expected to occur in the second half of 2019. Corporate Services Our Corporate Services segment includes our Listing Services and Corporate Solutions businesses. 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 and private funds. In December 2018, we launched a Corporate Bond exchange for the listing and trading of corporate bonds. The new exchange operates pursuant to The Nasdaq Stock Market exchange license and is powered by the Nasdaq Financial Framework. As of June 30, 2019 , there were 3,080 total listings on The Nasdaq Stock Market, including 374 ETPs. The combined market capitalization was approximately $13.3 trillion . In Europe, the Nasdaq Nordic and Nasdaq Baltic exchanges, together with Nasdaq First North, were home to 1,029 listed companies with a combined market capitalization of approximately $1.5 trillion . Our Corporate Solutions business serves corporate clients, including companies listed on our exchanges and private companies. We help organizations enhance their ability to understand and expand their global shareholder base, and improve corporate governance through our suite of advanced technology, analytics, and consultative services. In March 2019, we sold our BWise enterprise governance, risk and compliance software platform and in April 2018, we sold our Public Relations Solutions and Digital Media Services businesses. See Note 5, “Acquisitions and Divestitures,” for further discussion. As of March 2019, our Corporate Solutions business includes our Investor Relations Intelligence and Governance Solutions businesses. As of December 31, 2018, BWise was classified as held for sale. See Note 6, “Assets and Liabilities Held for Sale,” for further discussion. For segment reporting purposes, we have included the revenues and expenses of BWise and the Public Relations Solutions and Digital Media Services businesses in corporate items. These businesses were part of the Corporate Solutions business, within our Corporate Services segment, prior to the date of sale. For discussion of business segments, see Note 19, “Business Segments.” Information Services Our Information Services segment includes our Market Data, Index and Investment Data & Analytics businesses. Our Market Data 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 market data products enhance transparency of market activity within our exchanges and provide critical information to professional and non-professional investors globally. Our Index business develops and licenses Nasdaq-branded indexes, associated derivatives, and financial products and also provides custom calculation services for third-party clients. As of June 30, 2019 , we had 341 ETPs licensed to Nasdaq’s indexes which had $203 billion in assets under management. Our Investment Data & Analytics business is a leading content and analytics cloud-based solutions provider used by asset managers, investment consultants and asset owners to help facilitate better investment decisions. 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, buy-side firms 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 100 marketplaces in 50 countries. Market Technology also provides market surveillance services to broker-dealer firms worldwide, as well as risk management solutions.

Basis of Presentation and Princ

Basis of Presentation and Principles of Consolidation	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The condensed 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 8, “Investments,” for further discussion of our equity method investments. The accompanying condensed 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. As permitted under U.S. GAAP, certain footnotes or other financial information can be condensed or omitted in the interim condensed consolidated financial statements. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and accompanying notes included in Nasdaq’s Form 10-K. The year-end condensed balance sheet data was derived from the audited financial statements, but does not include all disclosures required by U.S. GAAP. On January 1, 2019, we adopted ASU 2016-02, “Leases,” or ASU 2016-02. See Note 3, “Significant Accounting Policies Update,” for further discussion. Certain prior year amounts have been reclassified to conform to the current year presentation. The preparation of condensed 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 condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates. Subsequent Events We have evaluated subsequent events through the issuance date of this Quarterly Report on Form 10-Q. Recent Accounting Pronouncements 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. January 1, 2020, with early adoption permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We will adopt this standard on January 1, 2020. 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. 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. 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 will adopt this standard on January 1, 2020 and are currently assessing the impact that this standard will have on our consolidated financial statements. Any impact will be recognized as a cumulative-effect adjustment to retained earnings as of the effective date to align our credit loss methodology with the new standard.

Significant Accounting Policies

Significant Accounting Policies Update	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Significant Accounting Policies Update	Significant Accounting Policies Update Our significant accounting policies are detailed in Note 2, “Summary of Significant Accounting Policies,” in our Form 10-K. A significant change to our accounting policies as a result of adopting ASU 2016-02 is discussed below. We adopted ASU 2016-02 on January 1, 2019, and elected the optional transition method to initially apply the standard at the January 1, 2019 adoption date. As a result, we applied the new lease standard prospectively to our leases existing or commencing on or after January 1, 2019. Comparative periods presented were not restated upon adoption. Similarly, new disclosures under the standard were made for periods beginning January 1, 2019, and not for prior comparative periods. Prior periods will continue to be reported under guidance in effect prior to January 1, 2019. In addition, w e elected the package of practical expedients permitted under the transition guidance within the standard, which among other things, allowed us to not reassess contracts to determine if they contain leases, lease classification and initial direct costs. The standard did not impact our statements of income and had no impact on our cash flows. We have operating leases which are primarily real estate leases for our U.S. and European headquarters and for general office space. These leases have varying lease terms ranging from 3 months to 17 years. We determine if an arrangement is a lease at inception. Operating leases are included in operating lease assets, other current liabilities, and operating lease liabilities in our condensed consolidated balance sheets as of June 30, 2019 . As of June 30, 2019 , we do not have any finance leases. Operating lease assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Since our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The operating lease asset also includes any lease payments made and excludes lease incentives. Our lease terms include options to extend or terminate the lease when we are reasonably certain that we will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. Certain of our lease agreements include rental payments adjusted periodically for inflation based on an index or rate. These payments are included in the initial measurement of the operating lease liability and operating lease asset. However, rental payments that are based on a change in an index or a rate are considered variable lease payments and are expensed as incurred. We have lease agreements with lease and non-lease components, which are accounted for as a single performance obligation to the extent that the timing and pattern of transfer are similar for the lease and non-lease components and the lease component qualifies as an operating lease . We do not recognize lease liabilities and operating lease assets for leases with a term of 12 months or less. We recognize these lease payments on a straight-line basis over the lease term. Our lease agreements do not contain any material residual value guarantees or material restrictions or covenants. We sublease certain real estate to third parties. Our sublease portfolio consists of operating leases. The following table provides supplemental balance sheet information related to Nasdaq's operating leases: Leases Balance Sheet Classification June 30, 2019 (in millions) Assets: Operating lease assets Operating lease assets $ 365 Liabilities: Current lease liabilities Other current liabilities $ 61 Non-current lease liabilities Operating lease liabilities 343 Total lease liabilities $ 404 The following table summarizes Nasdaq's lease cost: Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 (in millions) Operating lease cost (1) $ 19 $ 39 Variable lease cost 7 12 Sublease income (2 ) (3 ) Total lease cost $ 24 $ 48 ____________ (1) Includes short-term lease cost, which was immaterial. The following table reconciles the undiscounted cash flows for each of the first five years and total of the remaining years to the operating lease liabilities recorded in our condensed consolidated balance sheet. June 30, 2019 (in millions) 2019 (1) $ 40 2020 76 2021 66 2022 44 2023 39 Thereafter 261 Total lease payments 526 Less: interest (2) (122 ) Present value of lease liabilities (3) $ 404 ____________ (1) Represents the estimated lease payments to be made for the remaining six months of 2019. (2) Calculated using the interest rate for each lease. (3) Includes the current portion of $61 million . Total lease payments in the above table exclude $128 million of legally binding minimum lease payments for leases signed but not yet commenced related to the expansion of our world headquarters. These leases will commence in 2020 with a lease term of 16 years. The following table provides information related to Nasdaq's lease term and discount rate: June 30, 2019 Weighted-average remaining lease term (in years) 10.4 Weighted-average discount rate 4.6 % The following table provides supplemental cash flow information related to Nasdaq's operating leases: Six Months Ended June 30, 2019 (in millions) Cash paid for amounts included in the measurement of operating lease liabilities $ 38 Lease assets obtained in exchange for new operating lease liabilities $ 20

Revenue From Contracts With Cus

Revenue From Contracts With Customers	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue From Contracts With Customers	Revenue From Contracts With Customers Disaggregation of Revenue The following tables summarize the disaggregation of revenue by major product and service and by segment for the three and six months ended June 30, 2019 and 2018 : Three Months Ended June 30, 2019 Market Services Corporate Services Information Services Market Technology Consolidated (in millions) Transaction-based trading and clearing, net $ 154 $ — $ — $ — $ 154 Trade management services 73 — — — 73 Listing services — 74 — — 74 Corporate solutions — 49 — — 49 Market data products — — 100 — 100 Index — — 55 — 55 Investment data & analytics — — 39 — 39 Market technology — — — 79 79 Revenues less transaction-based expenses $ 227 $ 123 $ 194 $ 79 $ 623 Three Months Ended June 30, 2018 Market Services Corporate Services Information Services Market Technology Other Revenues Consolidated (in millions) Transaction-based trading and clearing, net $ 164 $ — $ — $ — $ — $ 164 Trade management services 73 — — — — 73 Listing services — 72 — — — 72 Corporate solutions — 48 — — — 48 Market data products — — 98 — — 98 Index — — 50 — — 50 Investment data & analytics — — 27 — — 27 Market technology — — — 66 — 66 Other revenues — — — — 17 17 Revenues less transaction-based expenses $ 237 $ 120 $ 175 $ 66 $ 17 $ 615 For the three months ended June 30, 2019 , approximately 64.0% of Market Services revenues were recognized at a point in time and 36.0% were recognized over time. For the three months ended June 30, 2018 , approximately 65.0% of Market Services revenues were recognized at a point in time and 35.0% were recognized over time. Substantially all revenues from the Corporate Services, Information Services and Market Technology segments were recognized over time for both the three months ended June 30, 2019 and 2018. Six Months Ended June 30, 2019 Market Services Corporate Services Information Services Market Technology Other Revenues Consolidated (in millions) Transaction-based trading and clearing, net $ 315 $ — $ — $ — $ — $ 315 Trade management services 146 — — — — 146 Listing services — 145 — — — 145 Corporate solutions — 98 — — — 98 Market data products — — 200 — — 200 Index — — 109 — — 109 Investment data & analytics — — 78 — — 78 Market technology — — — 156 — 156 Other revenues — — — — 10 10 Revenues less transaction-based expenses $ 461 $ 243 $ 387 $ 156 $ 10 $ 1,257 Six Months Ended June 30, 2018 Market Services Corporate Services Information Services Market Technology Other Revenues Consolidated (in millions) Transaction-based trading and clearing, net $ 339 $ — $ — $ — $ — $ 339 Trade management services 148 — — — — 148 Listing services — 144 — — — 144 Corporate solutions — 99 — — — 99 Market data products — — 197 — — 197 Index — — 100 — — 100 Investment data & analytics — — 51 — — 51 Market technology — — — 126 — 126 Other revenues — — — — 77 77 Revenues less transaction-based expenses $ 487 $ 243 $ 348 $ 126 $ 77 $ 1,281 For both the six months ended June 30, 2019 and 2018, approximately 65.0% of Market Services revenues were recognized at a point in time and 35.0% were recognized over time. Substantially all revenues from the Corporate Services, Information Services and Market Technology segments were recognized over time for both the six months ended June 30, 2019 and 2018. * * * * * * Contract Balances Substantially all of our revenues are considered to be revenues from contracts with customers. The related accounts receivable balances are recorded in our Condensed Consolidated Balance Sheets as receivables which are net of allowance for doubtful accounts of $12 million as of June 30, 2019 and $13 million as of December 31, 2018 . The changes in the balance between periods were immaterial. We do not have obligations for warranties, returns or refunds to customers. For the majority of our contracts with customers, except for our market technology and listings services contracts, our performance obligations are short-term in nature and there is no significant variable consideration. We do not have revenues recognized from performance obligations that were satisfied in prior periods. We have elected not to provide disclosures about transaction price allocated to unsatisfied performance obligations if contract durations are less than one year. Excluding our market technology contracts, for contract durations that are one-year or greater, materially all of the transaction price allocated to unsatisfied performance obligations is included in deferred revenue. For our market technology contracts, the portion of transaction price allocated to unsatisfied performance obligations is shown in the table below. Deferred revenue primarily represents our contract liabilities related to our fees for annual and initial listings, market technology, corporate solutions and information services contracts. Deferred revenue is the only significant contract asset or liability as of June 30, 2019 . See Note 9, “Deferred Revenue,” for our discussion on deferred revenue balances, activity, and expected timing of recognition. Transaction Price Allocated to Remaining Performance Obligations As stated above, for contract durations that are one-year or greater, we do not have a material portion of transaction price allocated to unsatisfied performance obligations that are not included in deferred revenue other than for our market technology contracts. For our market technology contracts, t he following table summarizes the amount of the transaction price allocated to performance obligations that are unsatisfied as of June 30, 2019 : (in millions) 2019 (1) $ 150 2020 286 2021 132 2022 86 2023 46 2024 and thereafter 86 Total $ 786 ____________ (1) Represents performance obligations to be recognized over the remaining six months of 2019. Market technology deferred revenue, as discussed in Note 9, “Deferred Revenue,” to the condensed consolidated financial statements, represents consideration received that is yet to be recognized as revenue for unsatisfied performance obligations. Deferred revenue represents consideration received that is yet to be recognized as revenue. The changes in our deferred revenue during the six months ended June 30, 2019 are reflected in the following table: Initial Listing Revenues Annual Listings Revenues Market Technology Revenues Corporate Solutions Revenues Information Services Revenues Other (1) Total (in millions) Balance at December 31, 2018 $ 66 $ 4 $ 75 $ 36 $ 80 $ 20 $ 281 Deferred revenue billed in the current period, net of recognition 18 118 28 30 67 6 267 Revenue recognized that was included in the beginning of the period (16 ) (2 ) (29 ) (28 ) (58 ) (7 ) (140 ) Translation adjustment (2 ) — (4 ) — — (1 ) (7 ) Balance at June 30, 2019 $ 66 $ 120 $ 70 $ 38 $ 89 $ 18 $ 401 ____________ (1) Primarily includes deferred revenue from U.S. listing of additional shares fees which will continue to run-off as a result of the implementation of our all-inclusive annual fee. Listing of additional shares fees are included in our Listing Services business. The deferred revenue billed in the current period, net of recognition primarily pertains to our Market Services business. As of June 30, 2019 , we estimate that our deferred revenue will be recognized in the following years: Initial Listing Revenues Annual Listings Revenues Market Technology Revenues Corporate Solutions Revenues Information Services Revenues Other (1) Total (in millions) Fiscal year ended: 2019 (2) $ 12 $ 120 $ 35 $ 31 $ 67 $ 7 $ 272 2020 24 — 27 7 22 7 87 2021 13 — 8 — — 3 24 2022 9 — — — — 1 10 2023 5 — — — — — 5 2024 and thereafter 3 — — — — — 3 Total $ 66 $ 120 $ 70 $ 38 $ 89 $ 18 $ 401 ____________ (1) Other primarily includes revenues from U.S. listing of additional shares fees which are included in our Listing Services business. (2) Represents the estimated amortization to be recognized for the remaining six months of 2019. 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.

Acquisitions and Divestiture

Acquisitions and Divestiture	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Acquisitions and Divestiture	Acquisitions and Divestitures 2019 Divestiture and Acquisition We completed the following divestiture and acquisition in 2019. Financial results of each transaction are included in our condensed consolidated financial statements from the date of each divestiture or acquisition. 2019 Divestiture In March 2019, we sold our BWise enterprise governance, risk and compliance software platform, which was part of our Corporate Solutions business within our Corporate Services segment, to SAI Global and recognized a pre-tax gain on the sale of $27 million , net of disposal costs ( $20 million after tax). The pre-tax gain is included in net gain on divestiture of businesses in the Condensed Consolidated Statements of Income for the six months ended June 30, 2019. As of December 31, 2018, the assets and liabilities of BWise were held for sale. See Note 6, “Assets and Liabilities Held For Sale,” for further discussion. 2019 Acquisition Purchase Consideration Total Net Assets Acquired Total Net Deferred Tax Liability Acquired Goodwill (in millions) Cinnober $ 219 $ 22 $ (19 ) $ 79 $ 137 In January 2019, we acquired Cinnober, a Swedish financial technology provider to brokers, exchanges and clearinghouses worldwide for $219 million . Cinnober is part of our Market Technology segment. Nasdaq used cash on hand to fund this acquisition. The amounts in the table above represent the preliminary allocation of purchase price as of June 30, 2019 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 Cinnober acquisition. 2018 Acquisition and Divestiture We completed an acquisition during the year ended December 31, 2018 and a divestiture in April 2018. Financial results of each transaction are included in our condensed consolidated financial statements from the date of the acquisition or divestiture. 2018 Acquisition Acquisition of Quandl In November 2018, we acquired Quandl, Inc., a leading provider of alternative and core financial data. Quandl is part of our Information Services segment. Nasdaq used issuances of commercial paper to fund this acquisition. 2018 Divestiture In April 2018, we sold our Public Relations Solutions and Digital Media Services businesses which were part of our Corporate Solutions business to West Corporation. A pre-tax gain of $41 million , net of disposal costs ( $19 million after tax) was included in the Condensed Consolidated Statements of Income in the second quarter of 2018. A post-closing working capital adjustment of $8 million ( $5 million after tax) was included in the Condensed Consolidated Statements of Income in the third quarter of 2018 bringing the net gain on the sale to $33 million ( $14 million after tax) for the nine months ended September 30, 2018. The pretax gain of $41 million is included in gain on divestiture of businesses in the Condensed Consolidated Statements of Income for the three and six months ended June 30, 2018. Through a multi-year partnership with West, Nasdaq will continue to provide eligible Nasdaq-listed clients with access to public relations, webcasting and webhosting products and services as part of the terms of the transaction. As part of the terms of the transaction, we provided transition services to West, such as technology, finance and facilities related services until mid-2019, and the compensation received for such transition services was reflected as a reduction to the underlying expenses incurred by Nasdaq to provide such transition services. Intangible Assets The following table presents the details of the customer relationships intangible asset at the date of acquisition for Cinnober which was the significant acquired intangible asset for this acquisition. All acquired intangible assets with finite lives are amortized using the straight-line method. ($ in millions) Customer relationships $ 67 Discount rate used 9.5 % Estimated average useful life 13 years Customer Relationships Customer relationships represent the non-contractual and contractual relationships with customers. Methodology 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. 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 acquisition of Cinnober, 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 5 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. Pro Forma Results and Acquisition-related Costs The condensed consolidated financial statements for the three and six months ended June 30, 2019 include the financial results of the above acquisitions from the date of each acquisition. Pro forma financial results 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 Condensed Consolidated Statements of Income.

Assets and Liabilities Held For

Assets and Liabilities Held For Sale	6 Months Ended
	Jun. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Assets and Liabilities Held For Sale	Assets and Liabilities Held For Sale In 2018, we decided to sell BWise, our enterprise governance, risk and compliance software platform and this business was recorded as held for sale as of December 31, 2018. BWise was part of our Corporate Solutions business within our Corporate Services segment. We determined that we met all of the criteria to classify the assets and liabilities of BWise as held for sale. The disposal of BWise did not represent a strategic shift that would have a major effect on our operations and financial results and was, therefore, not classified as discontinued operations. As a result of this classification, the assets and liabilities of this business were recorded at the lower of their carrying amount or fair value less costs to sell. In February 2019, we entered into an agreement to sell BWise and in March 2019, we completed the sale and recognized a pre-tax gain on the sale of $27 million , net of disposal costs ( $20 million after tax). See “2019 Divestiture,” of Note 5, “Acquisitions and Divestitures,” for further discussion. Based on the sales price in the agreement, no impairment charge was recorded at the time of the sale as the carrying amount of the net assets was less than the sales price in the agreement less costs to sell. Major Classes of Assets and Liabilities Held For Sale The carrying amounts of the major classes of assets and liabilities that were classified as held for sale at December 31, 2018 were as follows: December 31, 2018 (in millions) Receivables, net $ 13 Property and equipment, net 10 Goodwill (1) 47 Intangible assets, net (2) 16 Other assets 3 Total assets held for sale (3) $ 89 Deferred tax liabilities $ 4 Deferred revenue 12 Other current liabilities 4 Total liabilities held for sale (4) $ 20 ____________ (1) The assignment of goodwill was based on the relative fair value of the disposal group and the portion of the remaining reporting unit. (2) Primarily represents customer relationships. (3) Included in other current assets in the Condensed Consolidated Balance Sheets as of December 31, 2018. (4) Included in other current liabilities in the Condensed Consolidated Balance Sheets as of December 31, 2018.

Goodwill and Acquired Intangibl

Goodwill and Acquired Intangible Assets	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Acquired Intangible Assets	Goodwill and Acquired Intangible Assets Goodwill The following table presents the changes in goodwill by business segment during the six months ended June 30, 2019 : Market Services Corporate Services Information Services Market Technology Total (in millions) Balance at December 31, 2018 $ 3,430 $ 455 $ 2,333 $ 145 $ 6,363 Goodwill acquired — — — 137 137 Foreign currency translation adjustment (58 ) (6 ) (43 ) (11 ) (118 ) Balance at June 30, 2019 $ 3,372 $ 449 $ 2,290 $ 271 $ 6,382 The goodwill acquired for Market Technology shown above relates to our acquisition of Cinnober. See “2019 Acquisition,” of Note 5, “Acquisitions and Divestitures,” for further discussion. 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 six months ended June 30, 2019 and 2018 ; 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: June 30, 2019 December 31, 2018 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 $ (18 ) $ 47 9 $ 54 $ (15 ) $ 39 9 Customer relationships 1,599 (484 ) 1,115 18 1,532 (456 ) 1,076 18 Other 18 (3 ) 15 8 17 (2 ) 15 8 Foreign currency translation adjustment (160 ) 52 (108 ) (149 ) 64 (85 ) Total finite-lived intangible assets $ 1,522 $ (453 ) $ 1,069 $ 1,454 $ (409 ) $ 1,045 Indefinite-Lived Intangible Assets Exchange and clearing registrations $ 1,257 $ — $ 1,257 $ 1,257 $ — $ 1,257 Trade names 121 — 121 122 — 122 Licenses 52 — 52 52 — 52 Foreign currency translation adjustment (195 ) — (195 ) (176 ) — (176 ) Total indefinite-lived intangible assets $ 1,235 $ — $ 1,235 $ 1,255 $ — $ 1,255 Total intangible assets $ 2,757 $ (453 ) $ 2,304 $ 2,709 $ (409 ) $ 2,300 Amortization expense for acquired finite-lived intangible assets was $26 million for the three months ended June 30, 2019 , $28 million for the three months ended June 30, 2018 , $51 million for the six months ended June 30, 2019 , and $56 million for the six months ended June 30, 2018 . Amortization expense decreased in 2019 primarily due to certain assets becoming fully amortized in the fourth quarter of 2018, partially offset by additional amortization expense associated with acquired intangible assets in 2019. These amounts are included in depreciation and amortization expense in the Condensed Consolidated Statements of Income. The estimated future amortization expense (excluding the impact of foreign currency translation adjustments of $108 million as of June 30, 2019 ) of acquired finite-lived intangible assets as of June 30, 2019 is as follows: (in millions) 2019 (1) $ 53 2020 105 2021 104 2022 101 2023 98 2024 and thereafter 716 Total $ 1,177 ____________ (1) Represents the estimated amortization to be recognized for the remaining six months of 2019.

Investments

Investments	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Investments	Investments The following table presents the details of our investments: June 30, December 31, (in millions) Trading securities $ 251 $ 259 Available-for-sale investment securities 8 9 Financial investments, at fair value $ 259 $ 268 Equity method investments $ 147 $ 135 Equity securities $ 68 $ 44 Financial Investments, at Fair Value Trading Securities Trading securities, which are included in financial investments, at fair value in the Condensed Consolidated Balance Sheets, are primarily comprised of highly rated European government debt securities, of which $180 million as of June 30, 2019 and $166 million as of December 31, 2018 , are assets primarily utilized to meet regulatory capital requirements, mainly for our clearing operations at Nasdaq Clearing. Available-for-Sale Investment Securities As of June 30, 2019 and December 31, 2018, available-for-sale investment securities, which are included in financial investments, at fair value in the Condensed Consolidated Balance Sheets, were primarily comprised of commercial paper. As of June 30, 2019 and December 31, 2018, the cumulative unrealized gains and losses on these securities were immaterial. Equity Method Investments As of June 30, 2019 and December 31, 2018 , our equity method investments primarily included our equity interest in OCC. The carrying amounts of our equity method investments are included in other non-current assets in the Condensed Consolidated Balance Sheets. Net income recognized from our equity interest in the earnings and losses of these equity method investments was $10 million for the three months ended June 30, 2019 , $5 million for the three months ended June 30, 2018 , $55 million for the six months ended June 30, 2019 , and $7 million for the six months ended June 30, 2018 . The change for the three and six months ended June 30, 2019 compared with the same periods in 2018 is primarily due to an increase in income recognized from our investment in OCC. Following the disapproval of the OCC capital plan in February 2019, described below, OCC suspended customer rebates and dividends to owners, including the unpaid dividend on 2018 results which Nasdaq expected to receive in March 2019. In 2018, we recorded $16 million of income relating to our share of OCC’s net income. We were not able to determine the impact of the disapproval of the OCC capital plan on OCC's 2018 net income until March 2019, when OCC's 2018 financial statements were made available to us. As a result, in March 2019, we recognized an additional $36 million of income relating to our share of OCC's net income for the year ended December 31, 2018. In March 2019 and in June 2019, we also recognized our share of OCC's quarterly 2019 net income which was $9 million in both the first and second quarters of 2019. OCC Capital Plan In March 2015, OCC implemented a capital plan under which the options exchanges that are OCC’s stockholders contributed $150 million of new equity capital to OCC, committed to make future replenishment capital contributions under certain circumstances, and received commitments regarding future dividend payments and related matters. Nasdaq PHLX and ISE each contributed $30 million of new equity capital under the OCC capital plan. OCC adopted specific policies with respect to fees, customer refunds and stockholder dividends, which envisioned an annual dividend equal to the portion of OCC’s after-tax income that exceeded OCC’s capital requirements after payment of refunds to OCC’s clearing members (such refunds were generally 50% of the portion of OCC’s pre-tax income that exceeded OCC’s capital requirements). In 2018, 2017 and 2016, OCC disbursed annual dividends under the capital plan and Nasdaq, as the beneficial owner of shares held by Nasdaq PHLX and ISE, received $13 million in 2018, $10 million in 2017 and $4 million in 2016. The dividend recorded by Nasdaq in 2016 did not include the dividend due to ISE because our acquisition of ISE was completed in June 2016, after that year’s dividend had been paid. In February 2016, after the SEC approved the rule change establishing the OCC capital plan, certain industry participants appealed that approval in the U.S. Court of Appeals. In February 2019, on remand from the Court of Appeals, the SEC disapproved the OCC rule change that established the capital plan. OCC began a phased return of capital contributed under the capital plan, and we received $44 million in February 2019, with the remainder to be repaid at a later date. As a result of the SEC's disapproval of the rule change, we are also released from any future capital replenishment obligations under the 2015 capital plan. Equity Securities The carrying amounts of our equity securities are included in other non-current assets in the Condensed Consolidated Balance Sheets. We elected the measurement alternative for primarily all of our equity securities as they do not have a readily determinable fair value. Under the measurement alternative, these securities 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. For the six months ended June 30, 2019 , no impairment charges were recorded on our equity securities and there were no upward or downward adjustments recorded. As of December 31, 2018, our equity securities primarily represent various strategic investments made through our corporate venture program. As of June 30, 2019 , our equity securities represent various strategic investments made through our c

Deferred Revenue

Deferred Revenue	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Deferred Revenue	Revenue From Contracts With Customers Disaggregation of Revenue The following tables summarize the disaggregation of revenue by major product and service and by segment for the three and six months ended June 30, 2019 and 2018 : Three Months Ended June 30, 2019 Market Services Corporate Services Information Services Market Technology Consolidated (in millions) Transaction-based trading and clearing, net $ 154 $ — $ — $ — $ 154 Trade management services 73 — — — 73 Listing services — 74 — — 74 Corporate solutions — 49 — — 49 Market data products — — 100 — 100 Index — — 55 — 55 Investment data & analytics — — 39 — 39 Market technology — — — 79 79 Revenues less transaction-based expenses $ 227 $ 123 $ 194 $ 79 $ 623 Three Months Ended June 30, 2018 Market Services Corporate Services Information Services Market Technology Other Revenues Consolidated (in millions) Transaction-based trading and clearing, net $ 164 $ — $ — $ — $ — $ 164 Trade management services 73 — — — — 73 Listing services — 72 — — — 72 Corporate solutions — 48 — — — 48 Market data products — — 98 — — 98 Index — — 50 — — 50 Investment data & analytics — — 27 — — 27 Market technology — — — 66 — 66 Other revenues — — — — 17 17 Revenues less transaction-based expenses $ 237 $ 120 $ 175 $ 66 $ 17 $ 615 For the three months ended June 30, 2019 , approximately 64.0% of Market Services revenues were recognized at a point in time and 36.0% were recognized over time. For the three months ended June 30, 2018 , approximately 65.0% of Market Services revenues were recognized at a point in time and 35.0% were recognized over time. Substantially all revenues from the Corporate Services, Information Services and Market Technology segments were recognized over time for both the three months ended June 30, 2019 and 2018. Six Months Ended June 30, 2019 Market Services Corporate Services Information Services Market Technology Other Revenues Consolidated (in millions) Transaction-based trading and clearing, net $ 315 $ — $ — $ — $ — $ 315 Trade management services 146 — — — — 146 Listing services — 145 — — — 145 Corporate solutions — 98 — — — 98 Market data products — — 200 — — 200 Index — — 109 — — 109 Investment data & analytics — — 78 — — 78 Market technology — — — 156 — 156 Other revenues — — — — 10 10 Revenues less transaction-based expenses $ 461 $ 243 $ 387 $ 156 $ 10 $ 1,257 Six Months Ended June 30, 2018 Market Services Corporate Services Information Services Market Technology Other Revenues Consolidated (in millions) Transaction-based trading and clearing, net $ 339 $ — $ — $ — $ — $ 339 Trade management services 148 — — — — 148 Listing services — 144 — — — 144 Corporate solutions — 99 — — — 99 Market data products — — 197 — — 197 Index — — 100 — — 100 Investment data & analytics — — 51 — — 51 Market technology — — — 126 — 126 Other revenues — — — — 77 77 Revenues less transaction-based expenses $ 487 $ 243 $ 348 $ 126 $ 77 $ 1,281 For both the six months ended June 30, 2019 and 2018, approximately 65.0% of Market Services revenues were recognized at a point in time and 35.0% were recognized over time. Substantially all revenues from the Corporate Services, Information Services and Market Technology segments were recognized over time for both the six months ended June 30, 2019 and 2018. * * * * * * Contract Balances Substantially all of our revenues are considered to be revenues from contracts with customers. The related accounts receivable balances are recorded in our Condensed Consolidated Balance Sheets as receivables which are net of allowance for doubtful accounts of $12 million as of June 30, 2019 and $13 million as of December 31, 2018 . The changes in the balance between periods were immaterial. We do not have obligations for warranties, returns or refunds to customers. For the majority of our contracts with customers, except for our market technology and listings services contracts, our performance obligations are short-term in nature and there is no significant variable consideration. We do not have revenues recognized from performance obligations that were satisfied in prior periods. We have elected not to provide disclosures about transaction price allocated to unsatisfied performance obligations if contract durations are less than one year. Excluding our market technology contracts, for contract durations that are one-year or greater, materially all of the transaction price allocated to unsatisfied performance obligations is included in deferred revenue. For our market technology contracts, the portion of transaction price allocated to unsatisfied performance obligations is shown in the table below. Deferred revenue primarily represents our contract liabilities related to our fees for annual and initial listings, market technology, corporate solutions and information services contracts. Deferred revenue is the only significant contract asset or liability as of June 30, 2019 . See Note 9, “Deferred Revenue,” for our discussion on deferred revenue balances, activity, and expected timing of recognition. Transaction Price Allocated to Remaining Performance Obligations As stated above, for contract durations that are one-year or greater, we do not have a material portion of transaction price allocated to unsatisfied performance obligations that are not included in deferred revenue other than for our market technology contracts. For our market technology contracts, t he following table summarizes the amount of the transaction price allocated to performance obligations that are unsatisfied as of June 30, 2019 : (in millions) 2019 (1) $ 150 2020 286 2021 132 2022 86 2023 46 2024 and thereafter 86 Total $ 786 ____________ (1) Represents performance obligations to be recognized over the remaining six months of 2019. Market technology deferred revenue, as discussed in Note 9, “Deferred Revenue,” to the condensed consolidated financial statements, represents consideration received that is yet to be recognized as revenue for unsatisfied performance obligations. Deferred revenue represents consideration received that is yet to be recognized as revenue. The changes in our deferred revenue during the six months ended June 30, 2019 are reflected in the following table: Initial Listing Revenues Annual Listings Revenues Market Technology Revenues Corporate Solutions Revenues Information Services Revenues Other (1) Total (in millions) Balance at December 31, 2018 $ 66 $ 4 $ 75 $ 36 $ 80 $ 20 $ 281 Deferred revenue billed in the current period, net of recognition 18 118 28 30 67 6 267 Revenue recognized that was included in the beginning of the period (16 ) (2 ) (29 ) (28 ) (58 ) (7 ) (140 ) Translation adjustment (2 ) — (4 ) — — (1 ) (7 ) Balance at June 30, 2019 $ 66 $ 120 $ 70 $ 38 $ 89 $ 18 $ 401 ____________ (1) Primarily includes deferred revenue from U.S. listing of additional shares fees which will continue to run-off as a result of the implementation of our all-inclusive annual fee. Listing of additional shares fees are included in our Listing Services business. The deferred revenue billed in the current period, net of recognition primarily pertains to our Market Services business. As of June 30, 2019 , we estimate that our deferred revenue will be recognized in the following years: Initial Listing Revenues Annual Listings Revenues Market Technology Revenues Corporate Solutions Revenues Information Services Revenues Other (1) Total (in millions) Fiscal year ended: 2019 (2) $ 12 $ 120 $ 35 $ 31 $ 67 $ 7 $ 272 2020 24 — 27 7 22 7 87 2021 13 — 8 — — 3 24 2022 9 — — — — 1 10 2023 5 — — — — — 5 2024 and thereafter 3 — — — — — 3 Total $ 66 $ 120 $ 70 $ 38 $ 89 $ 18 $ 401 ____________ (1) Other primarily includes revenues from U.S. listing of additional shares fees which are included in our Listing Services business. (2) Represents the estimated amortization to be recognized for the remaining six months of 2019. 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.

Debt Obligations

Debt Obligations	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Debt Obligations	Debt Obligations The following table presents the changes in the carrying amount of our debt obligations during the six months ended June 30, 2019 : December 31, 2018 Additions Payments, Accretion and Other June 30, 2019 Short-term debt: (in millions) Commercial paper $ 275 $ 1,866 $ (1,674 ) $ 467 Senior unsecured floating rate notes repaid on March 22, 2019 500 — (500 ) — 5.55% senior unsecured notes repaid on May 1, 2019 ( 1) 599 — (599 ) — $400 million senior unsecured term loan facility repaid on June 28, 2019 (average interest rate of 4.00% for the period January 1, 2019 through June 28, 2019) 100 — (100 ) — Total short-term debt 1,474 1,866 (2,873 ) 467 Long-term debt: 3.875% senior unsecured notes due June 7, 2021 686 — (6 ) 680 4.25% senior unsecured notes due June 1, 2024 497 — — 497 1.75% senior unsecured notes due May 19, 2023 682 — (5 ) 677 3.85% senior unsecured notes due June 30, 2026 496 — 1 497 1.75% senior unsecured notes due March 28, 2029 — 665 9 674 $1 billion senior unsecured revolving credit facility due April 25, 2022 (average interest rate of 5.60% for the period January 1, 2019 through June 30, 2019) (4 ) 15 (14 ) (3 ) Total long-term debt 2,357 680 (15 ) 3,022 Total debt obligations $ 3,831 $ 2,546 $ (2,888 ) $ 3,489 ____________ (1) Balance was reclassified to short-term debt as of March 31, 2019. Commercial Paper Program Our U.S. dollar 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 fluctuates as short term interest rates and demand fluctuate. The fluctuation of these rates due to market conditions may impact our interest expense. As of June 30, 2019 , 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 13 days to 63 days and the weighted-average maturity is 29 days . The weighted-average effective interest rate is 2.64% 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 June 30, 2019 , 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. 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. Senior Unsecured Floating Rate Notes In March 2019, we used net proceeds from the sale of commercial paper and cash on hand and repaid all of our 2019 Notes. Nasdaq issued the 2019 Notes in September 2017. The 2019 Notes paid 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. Early Extinguishment of 5.55% Senior Unsecured Notes Due 2020 Nasdaq issued the 2020 Notes in January 2010. The 2020 Notes paid interest semiannually at a rate of 5.55% % per annum. In May 2019, we primarily used the net proceeds from the 2029 Notes to repay in full and terminate our 2020 Notes. For further discussion of the 2029 Notes, see “ 1.75% Senior Unsecured Notes Due 2029” below. In connection with the early extinguishment of the 2020 Notes, we recorded a pre-tax charge of $11 million , which primarily included a make-whole redemption price premium. This charge is included in general, administrative and other expense in the Condensed Consolidated Statements of Income for both the three and six months ended June 30, 2019 . 3.875% Senior Unsecured Notes Due 2021 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 decrease in the carrying amount of $6 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 Condensed Consolidated Balance Sheets as of June 30, 2019 . 4.25% Senior Unsecured Notes Due 2024 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 Due 2023 In May 2016, Nasdaq issued the 2023 Notes. 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 decrease in the carrying amount of $5 million noted in the “Payments, Accretion and Other” column in the table above primarily reflects the translation of the 2023 Notes into U.S. dollars and is recorded in accumulated other comprehensive loss within stockholders’ equity in the Condensed Consolidated Balance Sheets as of June 30, 2019 . 3.85% Senior Unsecured Notes Due 2026 In June 2016, Nasdaq issued the 2026 Notes. 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% . 1.75% Senior Unsecured Notes Due 2029 In April 2019, Nasdaq issued the 2029 Notes at a discount. As a result of the discount, the proceeds received from the issuance were less than the aggregate principal amount. The 2029 Notes are unsecured, pay interest annually in arrears, beginning on March 28, 2020 at a rate of 1.75% per annum until March 28, 2029 and such rate may vary with Nasdaq’s debt rating up to a rate not to exceed 3.75% . The 2029 Notes may be redeemed by Nasdaq at any time, subject to a make-whole amount. The proceeds from the 2029 Notes, approximately $665 million after deducting the underwriting discount and expenses of this offering, were primarily used to redeem the 2020 Notes. For further discussion of the 2020 Notes, see “ 5.55% Senior Unsecured Notes Due 2020” above. The 2029 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 $9 million noted in the “Payments, Accretion and Other” column in the table above reflects the translation of the 2029 Notes into U.S. dollars and is recorded in accumulated other comprehensive loss within stockholders’ equity in the Condensed Consolidated Balance Sheets as of June 30, 2019 . Credit Facilities Early Extinguishment of 2016 Credit Facility In March 2016, Nasdaq entered into the 2016 Credit Facility. Under our 2016 Credit Facility, borrowings bore 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 varied with Nasdaq’s debt rating. In June 2019, we used proceeds from issuances of commercial paper to repay in full and terminate our 2016 Credit Facility. 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 a former credit facility. 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. Nasdaq is permitted to repay borrowings under our 2017 Credit Facility at any time in whole or in part, without penalty. As of June 30, 2019 , no amounts were outstanding on the 2017 Credit Facility. The $3 million balance represents unamortized debt issuance costs which are being accreted through interest expense over the life of the credit facility. Of the $1 billion that is available for borrowing, $469 million provides liquidity support for the commercial paper program and for a letter of credit. As such, as of June 30, 2019 , the total remaining amount available under the 2017 Credit Facility was $531 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. We are charged commitment fees of 0.125% to 0.4% , depending on our credit rating, whether or not amounts have been borrowed. These commitment fees are included in interest expense and were not material for both the three and six months ended June 30, 2019 and 2018. The 2017 Credit Facility contains 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 make certain restricted payments. The facility also contains 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. 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. 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 $211 million as of June 30, 2019 and $220 million as of December 31, 2018 in available liquidity, none of which was utilized. Debt Covenants As of June 30, 2019 , we were in compliance with the covenants of all of our debt obligations.

Retirement Plans

Retirement Plans	6 Months Ended
	Jun. 30, 2019
Retirement Benefits [Abstract]
Retirement Plans	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 Condensed Consolidated Statements of Income was $3 million for both the three months ended June 30, 2019 and 2018, $6 million for the six months ended June 30, 2019 , and $7 million for six months ended June 30, 2018 . 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 Condensed Consolidated Statements of Income and was $5 million for both the three months ended June 30, 2019 and 2018, $10 million for the six months ended June 30, 2019 , and $11 million for the six months ended June 30, 2018 .

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2019
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation We have a share-based compensation program for employees and non-employee directors. 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 three and six months ended June 30, 2019 and 2018 in the Condensed Consolidated Statements of Income: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in millions) Share-based compensation expense before income taxes $ 20 $ 18 $ 36 $ 33 Income tax benefit (6 ) (5 ) (10 ) (9 ) Share-based compensation expense after income taxes $ 14 $ 13 $ 26 $ 24 Common Shares Available Under Our Equity Plan As of June 30, 2019 , we had approximately 10.3 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 stock 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. Summary of Restricted Stock Activity The following table summarizes our restricted stock activity for the six months ended June 30, 2019 : Restricted Stock Number of Awards Weighted-Average Grant Date Fair Value Unvested balances at January 1, 2019 1,583,375 $ 68.62 Granted 576,036 $ 84.46 Vested (477,052 ) $ 59.15 Forfeited (102,894 ) $ 72.16 Unvested balances at June 30, 2019 1,579,465 $ 77.00 As of June 30, 2019 , $73 million of total unrecognized compensation cost related to restricted stock is expected to be recognized over a weighted-average period of 1.9 years . PSUs PSUs are based on performance measures that impact the amount of shares that each recipient will receive upon vesting. 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 The grant date fair value of PSUs under the one-year performance-based program is based on the closing stock price at the date of grant less the present value of future cash dividends. Under this program, an eligible employee receives a target grant of PSUs, but 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 one-year performance period. Compensation cost is recognized over the performance period and the three-year vesting period based on the probability that such performance measures will be achieved, taking into account an estimated forfeiture rate. During 2018, certain grants of PSUs with a one-year performance period exceeded the applicable performance parameters. As a result, an additional 51,914 units above target were considered granted in the first quarter of 2019 and are included in the below table. Three-Year PSU Program Under the three-year performance-based program, each eligible individual receives PSUs, subject to market conditions, 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, taking into account an estimated forfeiture rate, regardless of whether the market condition is satisfied, provided that the requisite service period has been completed. 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 2016 with a three-year performance period exceeded the applicable performance parameters. As a result, an additional 99,622 units above target were considered granted in the first quarter of 2019 and are included in the below table. 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 six months ended June 30, 2019 : Six Months Ended June 30, 2019 2018 Weighted-average risk free interest rate (1) 2.26 % 2.36 % Expected volatility (2) 16.5 % 18.7 % Weighted-average grant date share price $89.00 $ 86.24 Weighted-average fair value at grant date $97.65 $ 116.86 ____________ (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 six months ended June 30, 2019 : 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 January 1, 2019 314,231 $ 74.01 837,750 $ 96.57 Granted (1) 179,599 $ 83.56 397,553 $ 96.55 Vested (8,207 ) $ 64.91 (431,751 ) $ 93.25 Forfeited (20,958 ) $ 74.86 (6,101 ) $ 103.29 Unvested balances at June 30, 2019 464,665 $ 77.82 797,451 $ 98.31 ____________ (1) Includes target awards granted and certain additional awards granted based on overachievement of performance parameters. As of June 30, 2019 , $17 million of total unrecognized compensation cost related to the one-year PSU program is expected to be recognized over a weighted-average period of 1.6 years . For the three-year PSU program, $45 million of total unrecognized compensation cost is expected to be recognized over a weighted-average period of 1.6 years . Stock Options In January 2017, our CEO received 268,817 performance-based non-qualified stock options which will vest one-third annually over a three-year period, with each vesting contingent upon the achievement of annual performance parameters. On January 29, 2019, Nasdaq's management compensation committee and board of directors determined that the performance goal for 2018 was met, resulting in the settlement of the second tranche of the grant. There were no stock option awards granted during the six months ended June 30, 2019 . The weighted-average grant date fair value for the 2017 grant was $66.68 . We estimated the fair value of this stock option award using the Black-Scholes valuation model using the following assumptions: Expected life (in years) 6 Weighted-average risk free interest rate 2.1 % Expected volatility 25.6 % Dividend yield 1.92 % Our computation of expected life was based on an estimate of the average length of time between option grant and exercise. The interest rate for periods within the expected life of the award was based on the U.S. Treasury yield curve in effect at the time of grant. Our computation of expected volatility was an estimate of the future upward/downward fluctuations in the underlying share price. We used Nasdaq's historical volatility for the trailing 6-year period as of the grant date. Our computation of dividend yield was based on annualized dividends expressed as a percentage of share price. Summary of Stock Option Activity A summary of stock option activity for the six months ended June 30, 2019 is as follows: Number of Stock Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in millions) Outstanding at January 1, 2019 447,716 $ 49.25 5.51 $ 14 Exercised (53,408 ) 21.02 Forfeited (25 ) 20.10 Outstanding at June 30, 2019 394,283 $ 52.91 5.56 $ 17 Exercisable at June 30, 2019 305,927 $ 48.87 4.99 $ 14 The net cash proceeds from the exercise of 44,742 stock options for the three months ended June 30, 2019 and 53,408 stock options for the six months ended June 30, 2019 was $1 million in both periods. We received net cash proceeds of $1 million from the exercise of 53,805 stock options for the three months ended June 30, 2018 and $2 million from the exercise of 88,000 stock options for the six months ended June 30, 2018 . 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 June 28, 2019 of $96.17 and the exercise price, times the number of shares) based on stock options with an exercise price less than Nasdaq’s closing price of $96.17 as of June 28, 2019, 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 June 30, 2019 was 0.3 million and the weighted-average exercise price was $48.87 . As of June 30, 2018 , 0.3 million outstanding stock options were exercisable and the weighted-average exercise price was $35.98 . The total pre-tax intrinsic value of stock options exercised was $3 million for the three months ended June 30, 2019 , $4 million for the six months ended June 30, 2019 , $4 million for the three months ended June 30, 2018 , and $6 million for the six months ended June 30, 2018 . ESPP We have an ESPP under which approximately 1.7 million shares of our common stock have been reserved for future issuance as of June 30, 2019 . 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 which totaled $2 million for both the six months ended June 30, 2019

Nasdaq Stockholders_ Equity

Nasdaq Stockholders’ Equity	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Nasdaq Stockholders' Equity	Nasdaq Stockholders’ Equity Common Stock As of June 30, 2019 , 300,000,000 shares of our common stock were authorized, 171,288,122 shares were issued and 165,389,235 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 Condensed Consolidated Balance Sheets. Shares repurchased under our share repurchase program are currently retired and canceled and are therefore not included in the common stock in treasury balance. When treasury shares are reissued, they are recorded at the average cost of the treasury shares acquired. We held 5,898,887 shares of common stock in treasury as of June 30, 2019 and 5,544,321 shares as of December 31, 2018, 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 and PSUs. Share Repurchase Program In January 2018, our board of directors authorized an additional $500 million for the share repurchase program, increasing the aggregate authorized amount to $726 million . 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 share repurchase program has no defined expiration date. The following is a summary of our share repurchase activity, reported based on settlement date, for the six months ended June 30, 2019 and 2018: Six Months Ended June 30, 2019 2018 Number of shares of common stock repurchased 538,449 3,929,520 Average price paid per share $ 92.84 $ 86.58 Total purchase price (in millions) $ 50 $ 340 As discussed above in “Common Stock in Treasury, at Cost,” shares repurchased under our share repurchase program are currently retired and cancelled. As of June 30, 2019 , the remaining amount authorized for share repurchases under the program was $282 million . Other Repurchases of Common Stock During the first six months of 2019 , we repurchased 354,566 shares of our common stock in settlement of employee tax withholding obligations arising from the vesting of restricted stock and PSUs. 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 June 30, 2019 and December 31, 2018, no shares of preferred stock were issued or outstanding. * * * * * * Cash Dividends on Common Stock During the first six months of 2019, 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 29, 2019 $ 0.44 March 15, 2019 $ 73 March 29, 2019 April 23, 2019 0.47 June 14, 2019 77 June 28, 2019 $ 150 The total amount paid of $150 million was recorded in retained earnings in the Condensed Consolidated Balance Sheets at June 30, 2019 . In July 2019, the board of directors approved a regular quarterly cash dividend of $0.47 per share on our outstanding common stock. The dividend is payable on September 27, 2019 to shareholders of record at the close of business on September 13, 2019. The estimated amount of this dividend is $78 million . Future declarations of quarterly dividends and the establishment of future record and payment dates are subject to approval by the board of directors. Our board of directors maintains a dividend policy with the intention to provide stockholders with regular and growing dividends over the long term as earnings and cash flow grow.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table sets forth the computation of basic and diluted earnings per share: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Numerator: (in millions, except share and per share amounts) Net income attributable to common shareholders $ 174 $ 162 $ 421 $ 339 Denominator: Weighted-average common shares outstanding for basic earnings per share 165,596,174 165,748,107 165,470,767 166,331,583 Weighted-average effect of dilutive securities: Employee equity awards (1) 1,445,245 1,651,497 1,564,016 1,812,437 Weighted-average common shares outstanding for diluted earnings per share 167,041,419 167,399,604 167,034,783 168,144,020 Basic and diluted earnings per share: Basic earnings per share $ 1.05 $ 0.98 $ 2.54 $ 2.04 Diluted earnings per share $ 1.04 $ 0.97 $ 2.52 $ 2.02 ____________ (1) PSUs, which are considered contingently issuable, are included in the computation of dilutive earnings per share on a weighted average basis when management determines that the applicable performance criteria would have been met if the performance period ended as of the date of the relevant computation. Securities that were not included in the computation of diluted earnings per share because their effect was antidilutive were immaterial for the three and six months ended June 30, 2019

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments The following tables present our financial assets and financial liabilities that are measured at fair value on a recurring basis as of June 30, 2019 and December 31, 2018 . June 30, 2019 Total Level 1 Level 2 Level 3 Assets at Fair Value (in millions) Financial investments, at fair value $ 259 $ 164 $ 95 $ — Default fund and margin deposit investments 1,496 234 1,262 — Total assets at fair value $ 1,755 $ 398 $ 1,357 $ — December 31, 2018 Total Level 1 Level 2 Level 3 Assets at Fair Value (in millions) Financial investments, at fair value $ 268 $ 133 $ 135 $ — Default fund and margin deposit investments 1,649 327 1,322 — Total assets at fair value $ 1,917 $ 460 $ 1,457 $ — Liabilities at Fair Value Other financial instruments $ 112 $ — $ 112 $ — Total liabilities at fair value $ 112 $ — $ 112 $ — As of June 30, 2019 and December 31, 2018 , Level 1 financial investments, at fair value were primarily comprised of trading securities, mainly highly rated European government debt securities. As of June 30, 2019 and December 31, 2018 , Level 2 financial investments, at fair value were primarily comprised of trading securities, mainly time deposits and European mortgage bonds. Of the Level 1 and Level 2 financial investments, at fair value, $180 million as of June 30, 2019 and $166 million as of December 31, 2018 are assets primarily utilized to meet regulatory capital requirements, mainly for our clearing operations at Nasdaq Clearing. Our Level 1 default fund and margin deposit investments were primarily comprised of highly rated European and U.S. government debt securities. Level 2 default fund and margin deposit investments were primarily comprised of central bank certificates and reverse repurchase agreements, as of June 30, 2019 and December 31, 2018. Our Level 2 other financial instruments at December 31, 2018 include a liability associated with Nasdaq Clearing's requirement to fulfill the settlement of certain contracts of a defaulted member. The fair value of this guarantee was $112 million as of December 31, 2018 and is included in other current liabilities in the Condensed Consolidated Balance Sheets. Collateral of $112 million as of December 31, 2018 was recorded in other current assets which offsets this liability. See Note 16, “Clearing Operations,” for further discussion of default fund contributions and margin deposits. 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. Our investment in OCC is accounted for under the equity method of accounting. We have elected the measurement alternative for the majority of our equity securities, which primarily represent various strategic investments made through our corporate venture program. See “Equity Method Investments,” and “Equity Securities,” of Note 8, “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 $3.7 billion as of June 30, 2019 and $3.9 billion as of December 31, 2018 . 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 June 30, 2019 . 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 June 30, 2019 and December 31, 2018 , there were no non-financial assets measured at fair value on a non-recurring basis.

Clearing Operations

Clearing Operations	6 Months Ended
	Jun. 30, 2019
Due to and from Broker-Dealers and Clearing Organizations [Abstract]
Clearing Operations	Clearing Operations Nasdaq Clearing Nasdaq Clearing is authorized and supervised under EMIR as a multi-asset clearinghouse by the SFSA. Such authorization is effective for all member states of the European Union and certain other non-member states that are part of the European Economic Area, including Norway. 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, fuel oil 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, default fund and margin collateral requirements are calculated for each clearing member’s positions in accounts with the CCP. 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 align risk between Nasdaq Clearing and its clearing members. Nasdaq Commodities Clearing Default In September 2018, a member of the Nasdaq Clearing commodities market defaulted due to inability to post sufficient collateral to cover increased margin requirements for the positions of the relevant member, which had experienced losses due to sharp adverse movements in the Nordic - German power market spread. Nasdaq Clearing followed default procedures and offset the future market risk on the defaulting member’s positions. The default resulted in a loss of $133 million . In accordance with the liability waterfall, the first $8 million of the loss was allocated to Nasdaq Clearing’s junior capital and the remainder was allocated on a pro-rata basis to the commodities clearing members’ default funds. In September 2018, these funds were replenished . In December 2018, we initiated a capital relief program. The capital relief program was a voluntary program open to each commodities default fund participant; each such participant who agreed to the capital relief program received a proportion of the funds made available under the capital relief program as reflected by their proportionate share of the aggregate of the clearing members' default fund replenishments. As of June 30, 2019, we have disbursed substantially all of the $23 million offered through the program. As a result of the default, a liability of $112 million as of December 31, 2018 was recorded in other current liabilities. Collateral of $112 million as of December 31, 2018 was recorded in other current assets in the Condensed Consolidated Balance Sheets in order to allow Nasdaq Clearing to fulfill the settlement of certain contracts of the defaulted member arising from the default management process. We had established mitigating positions. As of June 30, 2019, these contracts and mitigating positions have either expired or were sold to a third party together with associated collateral. The collateral and liability were previously included in default funds and margin deposits. Default Fund Contributions and Margin Deposits As of June 30, 2019 , clearing member default fund contributions and margin deposits were as follows: June 30, 2019 Cash Contributions Non-Cash Contributions Total Contributions (in millions) Default fund contributions $ 438 $ 123 $ 561 Margin deposits 2,723 3,473 6,196 Total $ 3,161 $ 3,596 $ 6,757 In accordance with its investment policy, of the total cash contributions of $3,161 million , Nasdaq Clearing has invested $973 million in highly rated European and U.S. government debt securities or central bank certificates with maturity dates primarily 90 days or less and $523 million in reverse repurchase agreements secured with highly rated government securities with maturity dates that range from 3 days to 18 days . The carrying value of these securities approximates their fair value due to the short-term nature of the instruments and reverse repurchase agreements. The remainder of this balance was held in cash in demand deposit accounts at central banks and large, highly rated financial institutions. Of the total default fund contributions of $561 million , Nasdaq Clearing can utilize $473 million as capital resources in the event of a counterparty default. The remaining balance of $88 million pertains to member posted surplus balances. In the investment activity related to default fund and margin contributions, we are exposed to counterparty risk related to reverse repurchase agreement transactions, which reflect the risk that the counterparty might become insolvent and, thus, fail to meet its obligations to Nasdaq Clearing. We mitigate this risk by only engaging in transactions with high credit quality reverse repurchase agreement counterparties and by limiting the acceptable collateral under the reverse repurchase agreement to high quality issuers, primarily government securities and other securities explicitly guaranteed by a government. The value of the underlying security is monitored during the lifetime of the contract, and in the event the market value of the underlying security falls below the reverse repurchase amount, our clearinghouse may require additional collateral or a reset of the contract. Default Fund Contributions Required contributions 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 Condensed 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 June 30, 2019 , Nasdaq Clearing committed capital totaling $152 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 Condensed Consolidated Balance Sheets. The combined regulatory capital of the clearing members and Nasdaq Clearing is intended to secure the obligations of a clearing member exceeding such member’s own margin and default fund deposits 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 and are recorded in revenues. These cash deposits are recorded in default funds and margin deposits in the Condensed Consolidated Balance Sheets as both a current asset and a current liability. Pledged margin collateral is not recorded in our Condensed 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 and default fund 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 cleared 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, excluding any liability related to the Nasdaq commodities clearing default (see discussion above), the estimated liability was nominal and no liability was recorded as of June 30, 2019 . 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 $34 million as of June 30, 2019 ; • 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 $22 million as of June 30, 2019 ; 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 liability waterfall, 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. In addition to the capital held to withstand counterparty defaults described above, Nasdaq Clearing also has committed capital of $96 million to ensure that it can handle an orderly wind-down of its operation, and that it is adequately protected against investment, operational, legal, and business risks. Market Value of Derivative Contracts Outstanding The following table includes the market value of derivative contracts outstanding prior to netting: June 30, 2019 (in millions) Commodity and seafood options, futures and forwards (1)(2)(3) $ 411 Fixed-income options and futures (1)(2) 889 Stock options and futures (1)(2) 133 Index options and futures (1)(2) 84 Total $ 1,517 ____________ (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. Derivative Contracts Cleared The following table includes the total number of derivative contracts cleared through Nasdaq Clearing for the six months ended June 30, 2019 and 2018 : June 30, 2019 June 30, 2018 Commodity and seafood options, futures and forwards (1)(2) 267,006 1,162,716 Fixed-income options and futures 11,565,386 11,286,397 Stock options and futures 12,476,329 11,940,062 Index options and futures 23,877,389 24,641,397 Total 48,186,110 49,030,572 ____________ (1) The total volume in cleared power related to commodity contracts was 420 Terawatt hours (TWh) for the six months ended June 30, 2019 and 577 TWh for the six months ended June 30, 2018 . (2) In July 2018, the Nasdaq freight product offering was migrated to NFX, our U.S.-based futures exchange. The outstanding contract value of resale and repurchase agreements was $3.8 billion as of June 30, 2019 and $3.4 billion as of June 30, 2018 . The total number of contracts cleared was 3,787,315 for the six months ended June 30, 2019 and was 4,498,651 for the six months ended June 30, 2018 .

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income Tax Provision The following table shows our income tax provision and effective tax rate: Three Months Ended June 30, Percentage Change 2019 2018 (in millions) Income tax provision $ 65 $ 126 (48.4 )% Effective tax rate 27.2 % 43.8 % Six Months Ended June 30, Percentage Change 2019 2018 (in millions) Income tax provision $ 131 $ 188 (30.3 )% Effective tax rate 23.7 % 35.7 % The lower effective tax rate in the second quarter and first six months of 2019 is primarily due to the 2018 reversal of certain Swedish tax benefits recorded in prior periods. The lower effective tax rate in the first six months of 2019 was also impacted by a tax benefit from a dividends received deduction related to capital distributions from the OCC and the reversal of a previously accrued tax penalty in Finland. 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 history of pre-tax earnings and losses, are taken into account in assessing the ability to realize deferred tax assets. Tax Audits 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 2008 through 2016 are currently under examination by the Internal Revenue Service and we are subject to examination by the Internal Revenue Service for the year 2017. Several state tax returns are currently under examination by the respective tax authorities for the years 2007 through 2017. Non-U.S. tax returns are subject to examination by the respective tax authorities for the years 2009 through 2017. 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. In addition, other than the Swedish tax matter described below, we do not expect to settle any material tax audits in the next twelve months. The Swedish Tax Agency has disallowed certain interest expense deductions for the years 2013 - 2016. We appealed to the Lower Administrative Court for the years 2013 - 2015. In the first quarter of 2018, the Lower Administrative Court denied our appeal. We have appealed to the Administrative Court of Appeal. Through March 31, 2018, we had 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 and have paid $45 million through June 30, 2019. In the second quarter of 2018, the Administrative Court of Appeal decided similar cases against other taxpayers. Although we continue to assert the validity of these interest expense deductions, the decisions of the court lead us to conclude that we can no longer assert that we are more than likely to be successful in our appeal. As such, in 2018, we recorded tax expense of $41 million , or $0.24 per diluted share, which is net of any related U.S. tax benefits and reflects the impact of foreign currency translation. We record quarterly net tax expense of $1 million related to this matter. 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. Tax Cuts and Jobs Act On January 1, 2018, we adopted ASU 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (Topic 220).” As a result of the adoption of this standard, we recorded a reclassification of $142 million for stranded tax effects related to the Tax Cuts and Jobs Act from accumulated other comprehensive loss to retained earnings within stockholders’ equity in the Condensed Consolidated Balance Sheets as of June 30, 2018 . Of the $142 million of stranded tax effects, $135 million relates to the effect on net foreign currency translation gains and losses and $7 million relates to the effect on employee benefit plan adjustment gains and losses. These provisional amounts were finalized in the fourth quarter of 2018.

Commitments, Contingencies and

Commitments, Contingencies and Guarantees	6 Months Ended
	Jun. 30, 2019
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 16, “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 $11 million as of June 30, 2019 and $12 million as of December 31, 2018 . As discussed in “Other Credit Facilities,” of Note 10, “Debt Obligations,” clearing-related credit facilities, which are available in multiple currencies, totaled $211 million as of June 30, 2019 and $220 million as of December 31, 2018 , 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 Industrial and Commercial Bank of China Financial Services LLC, or ICBC. As of June 30, 2019 , we have contributed $15 million of clearing deposits to ICBC in connection with this clearing arrangement. These deposits are recorded in other current assets in our Condensed Consolidated Balance Sheets. Some of the trading activity in Execution Access is cleared by ICBC through the Fixed Income Clearing Corporation, with ICBC acting as agent. 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). 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 Condensed Consolidated Balance Sheets for these arrangements. However, no guarantee can be provided that these arrangements will at all times be sufficient. Other 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 16, “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 condensed 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 Condensed 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 June 30, 2019 , these escrow agreements provide for future payment by us of up to an aggregate of $12 million which is included in other current liabilities in the Condensed 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 Condensed Consolidated Balance Sheets for these arrangements. Oslo Børs VPS In February 2019, we, through our indirect wholly-owned subsidiary Nasdaq AB, made a public offer to acquire all of the issued shares of Oslo Børs VPS Holding ASA, or Oslo Børs VPS. In May 2019, another bidder secured the necessary commitments and approvals to acquire more than 50% of the Oslo Børs VPS shares, and as a result, we withdrew our offer. Legal and Regulatory Matters Litigation As previously disclosed, we 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. The plaintiffs appealed the judgment of dismissal to the United States Court of Appeals for the Second Circuit (although opting not to appeal the dismissal with respect to Barclays PLC or the dismissal of claims under Section 6(b) of the Exchange Act). 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. On May 18, 2018, the exchanges filed a motion to dismiss the amended complaint, raising issues not addressed in the proceedings to date. On May 28, 2019, the district court denied the exchanges’ renewed motion to dismiss. On June 17, 2019, the exchanges filed a motion to certify the district court’s order for immediate review by the Second Circuit and on July 16, 2019, the district court denied the motion. Given the preliminary nature of the proceedings, we are unable to estimate what, if any, liability may result from this litigation. However, we believe that the claims are without merit and will continue to litigate vigorously. Nasdaq Commodities Clearing Default During September 2018, a clearing member of Nasdaq Clearing's commodities market was declared in default. We are responding to requests for information and are cooperating fully with the SFSA in the associated regulatory audits. While we are currently unable to predict the outcome of this matter, we do not believe it will have a material impact on our consolidated financial statements. See “Nasdaq Commodities Clearing Default,” of Note 16, “Clearing Operations,” for further information on this event. SEC Decisions In recent years, certain industry groups have challenged the level of fees that U.S. exchanges charge for market data and connectivity. We have defeated two challenges in federal appeals court pertaining to market data and an additional challenge at the administrative level within the SEC. However, in October 2018, the SEC reversed that administrative decision and found that Nasdaq had not met a burden of demonstrating that certain challenged fees were fair and reasonable; we estimate that this decision will reduce our revenues by approximately $1 million . Nasdaq has appealed this decision to the U.S. Court of Appeals for the District of Columbia Circuit. In addition, the SEC remanded a series of additional challenges to market data and connectivity fees back to Nasdaq for further consideration. Nasdaq has also appealed this decision to the U.S. Court of Appeals for the District of Columbia Circuit. We are unable to predict the outcome or the timing of the ultimate resolution of these matters. Other Matters 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 inquiries. Management believes that censures, fines, penalties or other sanctions that could result from any ongoing examinations or inquiries 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. See “Tax Audits,” of Note 17, “Income Taxes,” for further discussion.

Business Segments

Business Segments	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Business Segments	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 business segments for the three and six months ended June 30, 2019 and 2018 : Market Services Corporate Services Information Services Market Technology Corporate Items Consolidated (in millions) Three Months Ended June 30, 2019 Total revenues $ 665 $ 123 $ 194 $ 79 $ — $ 1,061 Transaction-based expenses (438 ) — — — — (438 ) Revenues less transaction-based expenses 227 123 194 79 — 623 Operating income (loss) $ 127 $ 44 $ 122 $ 8 $ (45 ) $ 256 Three Months Ended June 30, 2018 Total revenues $ 649 $ 120 $ 175 $ 66 $ 17 $ 1,027 Transaction-based expenses (412 ) — — — — (412 ) Revenues less transaction-based expenses 237 120 175 66 17 615 Operating income (loss) $ 134 $ 34 $ 112 $ 9 $ (20 ) $ 269 Six Months Ended June 30, 2019 Total revenues $ 1,304 $ 243 $ 387 $ 156 $ 10 $ 2,100 Transaction-based expenses (843 ) — — — — (843 ) Revenues less transaction-based expenses 461 243 387 156 10 1,257 Operating income (loss) 263 87 246 15 (80 ) 531 Six Months Ended June 30, 2018 Total revenues $ 1,384 $ 243 $ 348 $ 126 $ 77 $ 2,178 Transaction-based expenses (897 ) — — — — (897 ) Revenues less transaction-based expenses 487 243 348 126 77 1,281 Operating income (loss) 281 76 225 11 (52 ) 541 Certain amounts are allocated to corporate items in our management reports as we believe they do not contribute to a meaningful evaluation of a particular segment's ongoing operating performance. These items, which are shown in the table below, include the following: 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 acquisitions and divestitures 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. The credit balance in merger and strategic initiative expense in the second quarter of 2018 relates to the reclass of costs incurred during the first quarter of 2018 to sell the Public Relations Solutions and Digital Media Services businesses. Since these businesses were sold during the second quarter of 2018, these costs have been included as a deduction to the gain on the sale of these businesses. 2019 and 2018 Divestitures: We have included in corporate items the revenues and expenses of BWise and the Public Relations Solutions and Digital Media Services businesses which were part of the Corporate Solutions business within our Corporate Services segment as BWise was sold in March 2019 and the Public Relations Solutions and Digital Media Services businesses were sold in April 2018. See “2019 Divestiture,” and “2018 Divestiture,” of Note 5, “Acquisitions and Divestitures,” for further discussion. Other significant items: We have included certain other charges or gains in corporate items, to the extent we believe they should be excluded when evaluating the ongoing operating performance of each individual segment. For the three and six months ended June 30, 2019, other significant items primarily included loss on extinguishment of debt. For the three and six months ended June 30, 2018 , other significant items included a sales and use tax charge which related to prior periods. 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. A summary of our corporate items is as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in millions) Revenues - divested businesses $ — $ 17 $ 10 $ 77 Expenses: Amortization expense of acquired intangible assets 26 28 51 56 Merger and strategic initiatives expense 5 (10 ) 14 — Extinguishment of debt 11 — 11 — Expenses - divested businesses — 16 8 67 Other 3 3 6 6 Total expenses 45 37 90 129 Operating loss $ (45 ) $ (20 ) $ (80 ) $ (52 )

Significant Accounting Polici_2

Significant Accounting Policies Update (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	The condensed 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 8, “Investments,” for further discussion of our equity method investments.
Consolidation	The accompanying condensed 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. As permitted under U.S. GAAP, certain footnotes or other financial information can be condensed or omitted in the interim condensed consolidated financial statements. The information included in this Quarterly Report on Form 10-Q should be read in conjunction with the consolidated financial statements and accompanying notes included in Nasdaq’s Form 10-K. The year-end condensed balance sheet data was derived from the audited financial statements, but does not include all disclosures required by U.S. GAAP. On January 1, 2019, we adopted ASU 2016-02, “Leases,” or ASU 2016-02. See Note 3, “Significant Accounting Policies Update,” for further discussion.
Reclassification	Certain prior year amounts have been reclassified to conform to the current year presentation.
Use of Estimates	The preparation of condensed 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 condensed consolidated financial statements and accompanying notes. Actual results could differ from those estimates.
Subsequent Events	Subsequent Events We have evaluated subsequent events through the issuance date of this Quarterly Report on Form 10-Q.
Recent Accounting Pronouncements	Recent Accounting Pronouncements 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. January 1, 2020, with early adoption permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We will adopt this standard on January 1, 2020. 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. 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. 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 will adopt this standard on January 1, 2020 and are currently assessing the impact that this standard will have on our consolidated financial statements. Any impact will be recognized as a cumulative-effect adjustment to retained earnings as of the effective date to align our credit loss methodology with the new standard.
Leases	We adopted ASU 2016-02 on January 1, 2019, and elected the optional transition method to initially apply the standard at the January 1, 2019 adoption date. As a result, we applied the new lease standard prospectively to our leases existing or commencing on or after January 1, 2019. Comparative periods presented were not restated upon adoption. Similarly, new disclosures under the standard were made for periods beginning January 1, 2019, and not for prior comparative periods. Prior periods will continue to be reported under guidance in effect prior to January 1, 2019. In addition, w e elected the package of practical expedients permitted under the transition guidance within the standard, which among other things, allowed us to not reassess contracts to determine if they contain leases, lease classification and initial direct costs. The standard did not impact our statements of income and had no impact on our cash flows. We have operating leases which are primarily real estate leases for our U.S. and European headquarters and for general office space. These leases have varying lease terms ranging from 3 months to 17 years. We determine if an arrangement is a lease at inception. Operating leases are included in operating lease assets, other current liabilities, and operating lease liabilities in our condensed consolidated balance sheets as of June 30, 2019 . As of June 30, 2019 , we do not have any finance leases. Operating lease assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Since our leases do not provide an implicit rate, we use our incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The operating lease asset also includes any lease payments made and excludes lease incentives. Our lease terms include options to extend or terminate the lease when we are reasonably certain that we will exercise that option. Lease expense for lease payments is recognized on a straight-line basis over the lease term. Certain of our lease agreements include rental payments adjusted periodically for inflation based on an index or rate. These payments are included in the initial measurement of the operating lease liability and operating lease asset. However, rental payments that are based on a change in an index or a rate are considered variable lease payments and are expensed as incurred. We have lease agreements with lease and non-lease components, which are accounted for as a single performance obligation to the extent that the timing and pattern of transfer are similar for the lease and non-lease components and the lease component qualifies as an operating lease . We do not recognize lease liabilities and operating lease assets for leases with a term of 12 months or less. We recognize these lease payments on a straight-line basis over the lease term. Our lease agreements do not contain any material residual value guarantees or material restrictions or covenants. We sublease certain real estate to third parties. Our sublease portfolio consists of operating leases.

Basis of Presentation and Pri_2

Basis of Presentation and Principles of Consolidation (Tables)	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of the Recent Accounting Pronouncements	Recent Accounting Pronouncements 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. January 1, 2020, with early adoption permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. We will adopt this standard on January 1, 2020. 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. 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. 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 will adopt this standard on January 1, 2020 and are currently assessing the impact that this standard will have on our consolidated financial statements. Any impact will be recognized as a cumulative-effect adjustment to retained earnings as of the effective date to align our credit loss methodology with the new standard.

Significant Accounting Polici_3

Significant Accounting Policies Update (Tables)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Supplemental Balance Sheet Information Related to Operating Leases	The following table provides supplemental balance sheet information related to Nasdaq's operating leases: Leases Balance Sheet Classification June 30, 2019 (in millions) Assets: Operating lease assets Operating lease assets $ 365 Liabilities: Current lease liabilities Other current liabilities $ 61 Non-current lease liabilities Operating lease liabilities 343 Total lease liabilities $ 404
Lease Cost and Supplemental Cash Flow Information	The following table summarizes Nasdaq's lease cost: Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 (in millions) Operating lease cost (1) $ 19 $ 39 Variable lease cost 7 12 Sublease income (2 ) (3 ) Total lease cost $ 24 $ 48 ____________ (1) Includes short-term lease cost, which was immaterial. The following table provides information related to Nasdaq's lease term and discount rate: June 30, 2019 Weighted-average remaining lease term (in years) 10.4 Weighted-average discount rate 4.6 % The following table provides supplemental cash flow information related to Nasdaq's operating leases: Six Months Ended June 30, 2019 (in millions) Cash paid for amounts included in the measurement of operating lease liabilities $ 38 Lease assets obtained in exchange for new operating lease liabilities $ 20
Operating Lease Maturity	The following table reconciles the undiscounted cash flows for each of the first five years and total of the remaining years to the operating lease liabilities recorded in our condensed consolidated balance sheet. June 30, 2019 (in millions) 2019 (1) $ 40 2020 76 2021 66 2022 44 2023 39 Thereafter 261 Total lease payments 526 Less: interest (2) (122 ) Present value of lease liabilities (3) $ 404 ____________ (1) Represents the estimated lease payments to be made for the remaining six months of 2019. (2) Calculated using the interest rate for each lease. (3) Includes the current portion of $61 million .

Revenue From Contracts With C_2

Revenue From Contracts With Customers (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	Six Months Ended June 30, 2019 Market Services Corporate Services Information Services Market Technology Other Revenues Consolidated (in millions) Transaction-based trading and clearing, net $ 315 $ — $ — $ — $ — $ 315 Trade management services 146 — — — — 146 Listing services — 145 — — — 145 Corporate solutions — 98 — — — 98 Market data products — — 200 — — 200 Index — — 109 — — 109 Investment data & analytics — — 78 — — 78 Market technology — — — 156 — 156 Other revenues — — — — 10 10 Revenues less transaction-based expenses $ 461 $ 243 $ 387 $ 156 $ 10 $ 1,257 Six Months Ended June 30, 2018 Market Services Corporate Services Information Services Market Technology Other Revenues Consolidated (in millions) Transaction-based trading and clearing, net $ 339 $ — $ — $ — $ — $ 339 Trade management services 148 — — — — 148 Listing services — 144 — — — 144 Corporate solutions — 99 — — — 99 Market data products — — 197 — — 197 Index — — 100 — — 100 Investment data & analytics — — 51 — — 51 Market technology — — — 126 — 126 Other revenues — — — — 77 77 Revenues less transaction-based expenses $ 487 $ 243 $ 348 $ 126 $ 77 $ 1,281 The following tables summarize the disaggregation of revenue by major product and service and by segment for the three and six months ended June 30, 2019 and 2018 : Three Months Ended June 30, 2019 Market Services Corporate Services Information Services Market Technology Consolidated (in millions) Transaction-based trading and clearing, net $ 154 $ — $ — $ — $ 154 Trade management services 73 — — — 73 Listing services — 74 — — 74 Corporate solutions — 49 — — 49 Market data products — — 100 — 100 Index — — 55 — 55 Investment data & analytics — — 39 — 39 Market technology — — — 79 79 Revenues less transaction-based expenses $ 227 $ 123 $ 194 $ 79 $ 623 Three Months Ended June 30, 2018 Market Services Corporate Services Information Services Market Technology Other Revenues Consolidated (in millions) Transaction-based trading and clearing, net $ 164 $ — $ — $ — $ — $ 164 Trade management services 73 — — — — 73 Listing services — 72 — — — 72 Corporate solutions — 48 — — — 48 Market data products — — 98 — — 98 Index — — 50 — — 50 Investment data & analytics — — 27 — — 27 Market technology — — — 66 — 66 Other revenues — — — — 17 17 Revenues less transaction-based expenses $ 237 $ 120 $ 175 $ 66 $ 17 $ 615
Remaining Performance Obligation, Expected Timing of Satisfaction	For our market technology contracts, t he following table summarizes the amount of the transaction price allocated to performance obligations that are unsatisfied as of June 30, 2019 : (in millions) 2019 (1) $ 150 2020 286 2021 132 2022 86 2023 46 2024 and thereafter 86 Total $ 786 ____________ (1) Represents performance obligations to be recognized over the remaining six months of 2019.

Acquisitions and Divestiture (T

Acquisitions and Divestiture (Tables)	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	2019 Acquisition Purchase Consideration Total Net Assets Acquired Total Net Deferred Tax Liability Acquired Goodwill (in millions) Cinnober $ 219 $ 22 $ (19 ) $ 79 $ 137
Acquired Finite Lived Intangible Assets in Acquisition	The following table presents the details of the customer relationships intangible asset at the date of acquisition for Cinnober which was the significant acquired intangible asset for this acquisition. All acquired intangible assets with finite lives are amortized using the straight-line method. ($ in millions) Customer relationships $ 67 Discount rate used 9.5 % Estimated average useful life 13 years

Assets and Liabilities Held F_2

Assets and Liabilities Held For Sale (Tables)	6 Months Ended
	Jun. 30, 2019
Discontinued Operations and Disposal Groups [Abstract]
Schedule of carrying amounts of assets and liabilities classified as held for sale	The carrying amounts of the major classes of assets and liabilities that were classified as held for sale at December 31, 2018 were as follows: December 31, 2018 (in millions) Receivables, net $ 13 Property and equipment, net 10 Goodwill (1) 47 Intangible assets, net (2) 16 Other assets 3 Total assets held for sale (3) $ 89 Deferred tax liabilities $ 4 Deferred revenue 12 Other current liabilities 4 Total liabilities held for sale (4) $ 20 ____________ (1) The assignment of goodwill was based on the relative fair value of the disposal group and the portion of the remaining reporting unit. (2) Primarily represents customer relationships. (3) Included in other current assets in the Condensed Consolidated Balance Sheets as of December 31, 2018. (4) Included in other current liabilities in the Condensed Consolidated Balance Sheets as of December 31, 2018.

Goodwill and Acquired Intangi_2

Goodwill and Acquired Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Goodwill	The following table presents the changes in goodwill by business segment during the six months ended June 30, 2019 : Market Services Corporate Services Information Services Market Technology Total (in millions) Balance at December 31, 2018 $ 3,430 $ 455 $ 2,333 $ 145 $ 6,363 Goodwill acquired — — — 137 137 Foreign currency translation adjustment (58 ) (6 ) (43 ) (11 ) (118 ) Balance at June 30, 2019 $ 3,372 $ 449 $ 2,290 $ 271 $ 6,382
Schedule of Acquired Finite-Lived Intangible Assets	The following table presents details of our total acquired intangible assets, both finite- and indefinite-lived: June 30, 2019 December 31, 2018 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 $ (18 ) $ 47 9 $ 54 $ (15 ) $ 39 9 Customer relationships 1,599 (484 ) 1,115 18 1,532 (456 ) 1,076 18 Other 18 (3 ) 15 8 17 (2 ) 15 8 Foreign currency translation adjustment (160 ) 52 (108 ) (149 ) 64 (85 ) Total finite-lived intangible assets $ 1,522 $ (453 ) $ 1,069 $ 1,454 $ (409 ) $ 1,045 Indefinite-Lived Intangible Assets Exchange and clearing registrations $ 1,257 $ — $ 1,257 $ 1,257 $ — $ 1,257 Trade names 121 — 121 122 — 122 Licenses 52 — 52 52 — 52 Foreign currency translation adjustment (195 ) — (195 ) (176 ) — (176 ) Total indefinite-lived intangible assets $ 1,235 $ — $ 1,235 $ 1,255 $ — $ 1,255 Total intangible assets $ 2,757 $ (453 ) $ 2,304 $ 2,709 $ (409 ) $ 2,300
Schedule of Acquired Indefinite-lived Intangible Assets	The following table presents details of our total acquired intangible assets, both finite- and indefinite-lived: June 30, 2019 December 31, 2018 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 $ (18 ) $ 47 9 $ 54 $ (15 ) $ 39 9 Customer relationships 1,599 (484 ) 1,115 18 1,532 (456 ) 1,076 18 Other 18 (3 ) 15 8 17 (2 ) 15 8 Foreign currency translation adjustment (160 ) 52 (108 ) (149 ) 64 (85 ) Total finite-lived intangible assets $ 1,522 $ (453 ) $ 1,069 $ 1,454 $ (409 ) $ 1,045 Indefinite-Lived Intangible Assets Exchange and clearing registrations $ 1,257 $ — $ 1,257 $ 1,257 $ — $ 1,257 Trade names 121 — 121 122 — 122 Licenses 52 — 52 52 — 52 Foreign currency translation adjustment (195 ) — (195 ) (176 ) — (176 ) Total indefinite-lived intangible assets $ 1,235 $ — $ 1,235 $ 1,255 $ — $ 1,255 Total intangible assets $ 2,757 $ (453 ) $ 2,304 $ 2,709 $ (409 ) $ 2,300
Estimated Future Amortization Expense	The estimated future amortization expense (excluding the impact of foreign currency translation adjustments of $108 million as of June 30, 2019 ) of acquired finite-lived intangible assets as of June 30, 2019 is as follows: (in millions) 2019 (1) $ 53 2020 105 2021 104 2022 101 2023 98 2024 and thereafter 716 Total $ 1,177 ____________ (1) Represents the estimated amortization to be recognized for the remaining six months of 2019.

Investments (Tables)

Investments (Tables)	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Schedule of Investments	The following table presents the details of our investments: June 30, December 31, (in millions) Trading securities $ 251 $ 259 Available-for-sale investment securities 8 9 Financial investments, at fair value $ 259 $ 268 Equity method investments $ 147 $ 135 Equity securities $ 68 $ 44

Deferred Revenue (Tables)

Deferred Revenue (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Changes in Deferred Revenue	The changes in our deferred revenue during the six months ended June 30, 2019 are reflected in the following table: Initial Listing Revenues Annual Listings Revenues Market Technology Revenues Corporate Solutions Revenues Information Services Revenues Other (1) Total (in millions) Balance at December 31, 2018 $ 66 $ 4 $ 75 $ 36 $ 80 $ 20 $ 281 Deferred revenue billed in the current period, net of recognition 18 118 28 30 67 6 267 Revenue recognized that was included in the beginning of the period (16 ) (2 ) (29 ) (28 ) (58 ) (7 ) (140 ) Translation adjustment (2 ) — (4 ) — — (1 ) (7 ) Balance at June 30, 2019 $ 66 $ 120 $ 70 $ 38 $ 89 $ 18 $ 401 ____________ (1) Primarily includes deferred revenue from U.S. listing of additional shares fees which will continue to run-off as a result of the implementation of our all-inclusive annual fee. Listing of additional shares fees are included in our Listing Services business. The deferred revenue billed in the current period, net of recognition primarily pertains to our Market Services business.
Estimated Deferred Revenue	As of June 30, 2019 , we estimate that our deferred revenue will be recognized in the following years: Initial Listing Revenues Annual Listings Revenues Market Technology Revenues Corporate Solutions Revenues Information Services Revenues Other (1) Total (in millions) Fiscal year ended: 2019 (2) $ 12 $ 120 $ 35 $ 31 $ 67 $ 7 $ 272 2020 24 — 27 7 22 7 87 2021 13 — 8 — — 3 24 2022 9 — — — — 1 10 2023 5 — — — — — 5 2024 and thereafter 3 — — — — — 3 Total $ 66 $ 120 $ 70 $ 38 $ 89 $ 18 $ 401 ____________ (1) Other primarily includes revenues from U.S. listing of additional shares fees which are included in our Listing Services business. (2) Represents the estimated amortization to be recognized for the remaining six months of 2019.

Debt Obligations (Tables)

Debt Obligations (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Changes in Debt Obligations	The following table presents the changes in the carrying amount of our debt obligations during the six months ended June 30, 2019 : December 31, 2018 Additions Payments, Accretion and Other June 30, 2019 Short-term debt: (in millions) Commercial paper $ 275 $ 1,866 $ (1,674 ) $ 467 Senior unsecured floating rate notes repaid on March 22, 2019 500 — (500 ) — 5.55% senior unsecured notes repaid on May 1, 2019 ( 1) 599 — (599 ) — $400 million senior unsecured term loan facility repaid on June 28, 2019 (average interest rate of 4.00% for the period January 1, 2019 through June 28, 2019) 100 — (100 ) — Total short-term debt 1,474 1,866 (2,873 ) 467 Long-term debt: 3.875% senior unsecured notes due June 7, 2021 686 — (6 ) 680 4.25% senior unsecured notes due June 1, 2024 497 — — 497 1.75% senior unsecured notes due May 19, 2023 682 — (5 ) 677 3.85% senior unsecured notes due June 30, 2026 496 — 1 497 1.75% senior unsecured notes due March 28, 2029 — 665 9 674 $1 billion senior unsecured revolving credit facility due April 25, 2022 (average interest rate of 5.60% for the period January 1, 2019 through June 30, 2019) (4 ) 15 (14 ) (3 ) Total long-term debt 2,357 680 (15 ) 3,022 Total debt obligations $ 3,831 $ 2,546 $ (2,888 ) $ 3,489 ____________ (1) Balance was reclassified to short-term debt as of March 31, 2019.

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2019
Share-based Payment Arrangement [Abstract]
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 three and six months ended June 30, 2019 and 2018 in the Condensed Consolidated Statements of Income: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in millions) Share-based compensation expense before income taxes $ 20 $ 18 $ 36 $ 33 Income tax benefit (6 ) (5 ) (10 ) (9 ) Share-based compensation expense after income taxes $ 14 $ 13 $ 26 $ 24
Summary of Restricted Stock Activity	The following table summarizes our restricted stock activity for the six months ended June 30, 2019 : Restricted Stock Number of Awards Weighted-Average Grant Date Fair Value Unvested balances at January 1, 2019 1,583,375 $ 68.62 Granted 576,036 $ 84.46 Vested (477,052 ) $ 59.15 Forfeited (102,894 ) $ 72.16 Unvested balances at June 30, 2019 1,579,465 $ 77.00
Schedule of Weighted-Average Assumptions Used to Determine the Weighted-Average Fair Values	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 six months ended June 30, 2019 : Six Months Ended June 30, 2019 2018 Weighted-average risk free interest rate (1) 2.26 % 2.36 % Expected volatility (2) 16.5 % 18.7 % Weighted-average grant date share price $89.00 $ 86.24 Weighted-average fair value at grant date $97.65 $ 116.86 ____________ (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 six months ended June 30, 2019 : 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 January 1, 2019 314,231 $ 74.01 837,750 $ 96.57 Granted (1) 179,599 $ 83.56 397,553 $ 96.55 Vested (8,207 ) $ 64.91 (431,751 ) $ 93.25 Forfeited (20,958 ) $ 74.86 (6,101 ) $ 103.29 Unvested balances at June 30, 2019 464,665 $ 77.82 797,451 $ 98.31 ____________ (1) Includes target awards granted and certain additional awards granted based on overachievement of performance parameters.
Summary of Stock Options, Valuation Assumptions	We estimated the fair value of this stock option award using the Black-Scholes valuation model using the following assumptions: Expected life (in years) 6 Weighted-average risk free interest rate 2.1 % Expected volatility 25.6 % Dividend yield 1.92 %
Summary of Stock Option Activity	A summary of stock option activity for the six months ended June 30, 2019 is as follows: Number of Stock Options Weighted-Average Exercise Price Weighted-Average Remaining Contractual Term (in years) Aggregate Intrinsic Value (in millions) Outstanding at January 1, 2019 447,716 $ 49.25 5.51 $ 14 Exercised (53,408 ) 21.02 Forfeited (25 ) 20.10 Outstanding at June 30, 2019 394,283 $ 52.91 5.56 $ 17 Exercisable at June 30, 2019 305,927 $ 48.87 4.99 $ 14

Nasdaq Stockholders_ Equity (Ta

Nasdaq Stockholders’ Equity (Tables)	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Common Stock in Treasury, at Cost	The following is a summary of our share repurchase activity, reported based on settlement date, for the six months ended June 30, 2019 and 2018: Six Months Ended June 30, 2019 2018 Number of shares of common stock repurchased 538,449 3,929,520 Average price paid per share $ 92.84 $ 86.58 Total purchase price (in millions) $ 50 $ 340
Schedule of Dividends Declared	During the first six months of 2019, 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 29, 2019 $ 0.44 March 15, 2019 $ 73 March 29, 2019 April 23, 2019 0.47 June 14, 2019 77 June 28, 2019 $ 150

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2019
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: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Numerator: (in millions, except share and per share amounts) Net income attributable to common shareholders $ 174 $ 162 $ 421 $ 339 Denominator: Weighted-average common shares outstanding for basic earnings per share 165,596,174 165,748,107 165,470,767 166,331,583 Weighted-average effect of dilutive securities: Employee equity awards (1) 1,445,245 1,651,497 1,564,016 1,812,437 Weighted-average common shares outstanding for diluted earnings per share 167,041,419 167,399,604 167,034,783 168,144,020 Basic and diluted earnings per share: Basic earnings per share $ 1.05 $ 0.98 $ 2.54 $ 2.04 Diluted earnings per share $ 1.04 $ 0.97 $ 2.52 $ 2.02 ____________ (1) PSUs, which are considered contingently issuable, are included in the computation of dilutive earnings per share on a weighted average basis when management determines that the applicable performance criteria would have been met if the performance period ended as of the date of the relevant computation.

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Schedule of Financial Assets Measured at Fair Value on Recurring Basis	The following tables present our financial assets and financial liabilities that are measured at fair value on a recurring basis as of June 30, 2019 and December 31, 2018 . June 30, 2019 Total Level 1 Level 2 Level 3 Assets at Fair Value (in millions) Financial investments, at fair value $ 259 $ 164 $ 95 $ — Default fund and margin deposit investments 1,496 234 1,262 — Total assets at fair value $ 1,755 $ 398 $ 1,357 $ — December 31, 2018 Total Level 1 Level 2 Level 3 Assets at Fair Value (in millions) Financial investments, at fair value $ 268 $ 133 $ 135 $ — Default fund and margin deposit investments 1,649 327 1,322 — Total assets at fair value $ 1,917 $ 460 $ 1,457 $ — Liabilities at Fair Value Other financial instruments $ 112 $ — $ 112 $ — Total liabilities at fair value $ 112 $ — $ 112 $ —

Clearing Operations (Tables)

Clearing Operations (Tables)	6 Months Ended
	Jun. 30, 2019
Due to and from Broker-Dealers and Clearing Organizations [Abstract]
Schedule of Clearing Member Default Fund Contributions	As of June 30, 2019 , clearing member default fund contributions and margin deposits were as follows: June 30, 2019 Cash Contributions Non-Cash Contributions Total Contributions (in millions) Default fund contributions $ 438 $ 123 $ 561 Margin deposits 2,723 3,473 6,196 Total $ 3,161 $ 3,596 $ 6,757
Schedule of Derivative Contracts Outstanding	The following table includes the market value of derivative contracts outstanding prior to netting: June 30, 2019 (in millions) Commodity and seafood options, futures and forwards (1)(2)(3) $ 411 Fixed-income options and futures (1)(2) 889 Stock options and futures (1)(2) 133 Index options and futures (1)(2) 84 Total $ 1,517 ____________ (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 following table includes the total number of derivative contracts cleared through Nasdaq Clearing for the six months ended June 30, 2019 and 2018 : June 30, 2019 June 30, 2018 Commodity and seafood options, futures and forwards (1)(2) 267,006 1,162,716 Fixed-income options and futures 11,565,386 11,286,397 Stock options and futures 12,476,329 11,940,062 Index options and futures 23,877,389 24,641,397 Total 48,186,110 49,030,572 ____________ (1) The total volume in cleared power related to commodity contracts was 420 Terawatt hours (TWh) for the six months ended June 30, 2019 and 577 TWh for the six months ended June 30, 2018 . (2) In July 2018, the Nasdaq freight product offering was migrated to NFX, our U.S.-based futures exchange.

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The following table shows our income tax provision and effective tax rate: Three Months Ended June 30, Percentage Change 2019 2018 (in millions) Income tax provision $ 65 $ 126 (48.4 )% Effective tax rate 27.2 % 43.8 % Six Months Ended June 30, Percentage Change 2019 2018 (in millions) Income tax provision $ 131 $ 188 (30.3 )% Effective tax rate 23.7 % 35.7 %

Business Segments (Tables)

Business Segments (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Schedule of Operating Segments	The following table presents certain information regarding our business segments for the three and six months ended June 30, 2019 and 2018 : Market Services Corporate Services Information Services Market Technology Corporate Items Consolidated (in millions) Three Months Ended June 30, 2019 Total revenues $ 665 $ 123 $ 194 $ 79 $ — $ 1,061 Transaction-based expenses (438 ) — — — — (438 ) Revenues less transaction-based expenses 227 123 194 79 — 623 Operating income (loss) $ 127 $ 44 $ 122 $ 8 $ (45 ) $ 256 Three Months Ended June 30, 2018 Total revenues $ 649 $ 120 $ 175 $ 66 $ 17 $ 1,027 Transaction-based expenses (412 ) — — — — (412 ) Revenues less transaction-based expenses 237 120 175 66 17 615 Operating income (loss) $ 134 $ 34 $ 112 $ 9 $ (20 ) $ 269 Six Months Ended June 30, 2019 Total revenues $ 1,304 $ 243 $ 387 $ 156 $ 10 $ 2,100 Transaction-based expenses (843 ) — — — — (843 ) Revenues less transaction-based expenses 461 243 387 156 10 1,257 Operating income (loss) 263 87 246 15 (80 ) 531 Six Months Ended June 30, 2018 Total revenues $ 1,384 $ 243 $ 348 $ 126 $ 77 $ 2,178 Transaction-based expenses (897 ) — — — — (897 ) Revenues less transaction-based expenses 487 243 348 126 77 1,281 Operating income (loss) 281 76 225 11 (52 ) 541
Schedule of Corporate Items	A summary of our corporate items is as follows: Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (in millions) Revenues - divested businesses $ — $ 17 $ 10 $ 77 Expenses: Amortization expense of acquired intangible assets 26 28 51 56 Merger and strategic initiatives expense 5 (10 ) 14 — Extinguishment of debt 11 — 11 — Expenses - divested businesses — 16 8 67 Other 3 3 6 6 Total expenses 45 37 90 129 Operating loss $ (45 ) $ (20 ) $ (80 ) $ (52 )

Organization and Nature of Op_2

Organization and Nature of Operations (Details) $ in Billions	6 Months Ended
	Jun. 30, 2019USD ($)exchange_traded_productmarketplacesegmentcompanyexchangecountry
Organization And Basis Of Presentation [Line Items]
Total number of listings on The Nasdaq Stock Market | company	4,000
Approximate combined market capitalization | $	$ 14,000
Number of operating segments | segment	4
Market Services
Organization And Basis Of Presentation [Line Items]
Number of derivative exchanges listing commodities offerings | exchange	2
Market Services | United States | Options Markets
Organization And Basis Of Presentation [Line Items]
Number of exchanges | exchange	6
Market Services | United States | Cash Equities Trading Markets
Organization And Basis Of Presentation [Line Items]
Number of exchanges | exchange	3
Corporate Services | United States
Organization And Basis Of Presentation [Line Items]
Total number of listings on The Nasdaq Stock Market | company	3,080
Approximate combined market capitalization | $	$ 13,300
ETPs and other listings listed on Nasdaq Stock Market | company	374
Corporate Services | Europe
Organization And Basis Of Presentation [Line Items]
Approximate combined market capitalization | $	$ 1,500
Total number of listed companies within Nordic and Baltic exchanges | company	1,029
Information Services
Organization And Basis Of Presentation [Line Items]
Number of exchange traded products licensed to Nasdaq's Indexes | exchange_traded_product	341
Assets management value | $	$ 203
Market Technology
Organization And Basis Of Presentation [Line Items]
Number of exchanges | marketplace	100
Number of countries services are provided | country	50

Significant Accounting Polici_4

Significant Accounting Policies Update (Narrative) (Details) $ in Millions	Jun. 30, 2019USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Future minimum payments on lease not yet commenced	$ 128
Terms of lease not yet commenced	16 years
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease terms of contract	3 months
Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease terms of contract	17 years

Significant Accounting Polici_5

Significant Accounting Policies Update (Summary of Supplemental Balance Sheet Information Related to Operating Leases) (Details) $ in Millions	Jun. 30, 2019USD ($)
Assets:
Operating lease assets	$ 365
Liabilities:
Current lease liabilities	61
Non-current lease liabilities	343
Total lease liabilities	$ 404

Significant Accounting Polici_6

Significant Accounting Policies Update (Lease Cost) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Accounting Policies [Abstract]
Operating lease cost	$ 19	$ 39
Variable lease cost	7	12
Sublease income	(2)	(3)
Total lease cost	$ 24	$ 48

Significant Accounting Polici_7

Significant Accounting Policies Update (Operating Lease Maturity) (Details) $ in Millions	Jun. 30, 2019USD ($)
Accounting Policies [Abstract]
2019	$ 40
2020	76
2021	66
2022	44
2023	39
Thereafter	261
Total lease payments	526
Less: interest	(122)
Present value of lease liabilities	404
Current lease liabilities	$ 61

Significant Accounting Polici_8

Significant Accounting Policies Update (Lease Terms and Discount Rate) (Details)	Jun. 30, 2019
Accounting Policies [Abstract]
Weighted-average remaining lease term (in years)	10 years 4 months 24 days
Weighted-average discount rate	4.60%

Significant Accounting Polici_9

Significant Accounting Policies Update (Supplemental Cash Flow Information) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Accounting Policies [Abstract]
Cash paid for amounts included in the measurement of operating lease liabilities	$ 38
Lease assets obtained in exchange for new operating lease liabilities	$ 20

Revenue From Contracts With C_3

Revenue From Contracts With Customers (Revenue by Product, Service and Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	$ 623	$ 615	$ 1,257	$ 1,281
Transaction-based trading and clearing, net
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	154	164	315	339
Trade management services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	73	73	146	148
Listing services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	74	72	145	144
Corporate solutions
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	49	48	98	99
Market data products
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	100	98	200	197
Index
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	55	50	109	100
Investment data & analytics
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	39	27	78	51
Market technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	79	66	156	126
Other revenues
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		17	10	77
Operating Segments | Market Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	227	237	461	487
Operating Segments | Corporate Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	123	120	243	243
Operating Segments | Information Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	194	175	387	348
Operating Segments | Market Technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	79	66	156	126
Operating Segments | Transaction-based trading and clearing, net | Market Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	154	164	315	339
Operating Segments | Transaction-based trading and clearing, net | Corporate Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Transaction-based trading and clearing, net | Information Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Transaction-based trading and clearing, net | Market Technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Trade management services | Market Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	73	73	146	148
Operating Segments | Trade management services | Corporate Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Trade management services | Information Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Trade management services | Market Technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Listing services | Market Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Listing services | Corporate Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	74	72	145	144
Operating Segments | Listing services | Information Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Listing services | Market Technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Corporate solutions | Market Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Corporate solutions | Corporate Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	49	48	98	99
Operating Segments | Corporate solutions | Information Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Corporate solutions | Market Technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Market data products | Market Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Market data products | Corporate Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Market data products | Information Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	100	98	200	197
Operating Segments | Market data products | Market Technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Index | Market Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Index | Corporate Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Index | Information Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	55	50	109	100
Operating Segments | Index | Market Technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Investment data & analytics | Market Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Investment data & analytics | Corporate Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Investment data & analytics | Information Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	39	27	78	51
Operating Segments | Investment data & analytics | Market Technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Market technology | Market Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Market technology | Corporate Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Market technology | Information Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	0	0	0	0
Operating Segments | Market technology | Market Technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses	$ 79	66	156	126
Operating Segments | Other revenues | Market Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Operating Segments | Other revenues | Corporate Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Operating Segments | Other revenues | Information Services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Operating Segments | Other revenues | Market Technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Other Revenues
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		17	10	77
Other Revenues | Transaction-based trading and clearing, net
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Other Revenues | Trade management services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Other Revenues | Listing services
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Other Revenues | Corporate solutions
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Other Revenues | Market data products
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Other Revenues | Index
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Other Revenues | Investment data & analytics
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Other Revenues | Market technology
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		0	0	0
Other Revenues | Other revenues
Disaggregation of Revenue [Line Items]
Revenues less transaction-based expenses		$ 17	$ 10	$ 77

Revenue From Contracts With C_4

Revenue From Contracts With Customers Revenue From Contracts With Customers (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Receivables net of allowance for doubtful accounts	$ 12		$ 12		$ 13
Market Services | Services transferred at a point in time
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue recognized (percentage)	64.00%	65.00%	65.00%	65.00%
Market Services | Services transferred over time
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue recognized (percentage)	36.00%	35.00%	35.00%	35.00%

Revenue From Contracts With C_5

Revenue From Contracts With Customers (Remaining Performance Obligation) (Details) - Market Technology $ in Millions	Jun. 30, 2019USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 150
Revenue, remaining performance obligation, expected timing of satisfaction	6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 286
Revenue, remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 132
Revenue, remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 86
Revenue, remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 46
Revenue, remaining performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 786
Revenue, remaining performance obligation, expected timing of satisfaction

Acquisitions and Divestiture (2

Acquisitions and Divestiture (2019 Divestiture and Acquisition) (Details) - USD ($) $ in Millions	1 Months Ended		6 Months Ended
	Mar. 31, 2019	Jan. 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
2019 Divestiture [Abstract]
Proceeds from divestiture of businesses			$ 108	$ 294
2019 Acquisition [Abstract]
Purchase Consideration			193	$ 0
Goodwill			$ 6,382		$ 6,363
Cinnober
2019 Acquisition [Abstract]
Purchase Consideration		$ 219
Total Net Liabilities Acquired		22
Total Net Deferred Tax Liability		(19)
Acquired Intangible Assets		79
Goodwill		$ 137
Disposal Group, Disposed of by Sale, Not Discontinued Operations | BWise
2019 Divestiture [Abstract]
Proceeds from divestiture of businesses	$ 27
Gain on divestiture of business, after tax	$ 20

Acquisitions and Divestiture _2

Acquisitions and Divestiture (2018 Divestiture) (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended		9 Months Ended
	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain on divestiture of businesses	$ 0		$ 41	$ 27	$ 41
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Public Relations Solutions and Digital Media Services
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net gain on divestiture of businesses			(41)		$ (41)	$ (33)
Gain on divestiture of business, after tax			$ 19			$ 14
Working capital adjustment		$ (8)
Working capital adjustment, after tax		$ 5

Acquisitions and Divestiture (I

Acquisitions and Divestiture (Intangible Assets) (Details) - Cinnober $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2019USD ($)	Dec. 31, 2018	Jan. 31, 2019USD ($)
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, finite-lived			$ 79
Customer relationships
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Intangible assets, finite-lived	$ 67
Estimated average useful life	13 years
Amortization period of intangible assets for tax purposes		5 years
Discount rate used | Customer relationships
Finite Lived And Indefinite Lived Intangible Assets [Line Items]
Discount rate used	0.095

Assets and Liabilities Held F_3

Assets and Liabilities Held For Sale (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended		9 Months Ended
	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2018	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses			$ 108	$ 294
Carrying Amount of Assets and Liabilities Held for Sale [Abstract]
Deferred revenue			$ 333			$ 194
BWise | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses	$ 27
Gain on divestiture of business, after tax	$ 20
Public Relations Solutions and Digital Media Services | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on divestiture of business, after tax		$ 19			$ 14
Public Relations Solutions and Digital Media Services | Disposal Group, Not Discontinued Operations
Carrying Amount of Assets and Liabilities Held for Sale [Abstract]
Receivables, net						13
Property and equipment, net						10
Goodwill						47
Intangible assets, net						16
Other assets						3
Total assets held for sale						89
Deferred tax liabilities						4
Deferred revenue						12
Other current liabilities						4
Total liabilities held for sale						$ 20

Goodwill and Acquired Intangi_3

Goodwill and Acquired Intangible Assets (Schedule of Changes in Goodwill) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Goodwill [Roll Forward]
Balance at beginning of period	$ 6,363
Goodwill acquired	137
Foreign currency translation adjustment	(118)
Balance at end of period	6,382
Market Services
Goodwill [Roll Forward]
Balance at beginning of period	3,430
Goodwill acquired	0
Foreign currency translation adjustment	(58)
Balance at end of period	3,372
Corporate Services
Goodwill [Roll Forward]
Balance at beginning of period	455
Goodwill acquired	0
Foreign currency translation adjustment	(6)
Balance at end of period	449
Information Services
Goodwill [Roll Forward]
Balance at beginning of period	2,333
Goodwill acquired	0
Foreign currency translation adjustment	(43)
Balance at end of period	2,290
Market Technology
Goodwill [Roll Forward]
Balance at beginning of period	145
Goodwill acquired	137
Foreign currency translation adjustment	(11)
Balance at end of period	$ 271

Goodwill and Acquired Intangi_4

Goodwill and Acquired Intangible Assets (Narrative) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Indefinite-lived Intangible Assets [Line Items]
Goodwill, impairment loss			$ 0	$ 0
Amortization expense of acquired intangible assets	$ 26,000,000	$ 28,000,000	51,000,000	$ 56,000,000
Net future amortization expense	1,069,000,000		1,069,000,000		$ 1,045,000,000
Foreign currency translation adjustment
Indefinite-lived Intangible Assets [Line Items]
Net future amortization expense	$ (108,000,000)		$ (108,000,000)		$ (85,000,000)

Goodwill and Acquired Intangi_5

Goodwill and Acquired Intangible Assets (Finite-Lived and Indefinite-Lived Intangible Assets) (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 1,522	$ 1,454
Accumulated Amortization	(453)	(409)
Net Amount	1,069	1,045
Indefinite-lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	1,235	1,255
Total intangible assets	2,757	2,709
Intangible assets, net	2,304	2,300
Exchange and clearing registrations
Indefinite-lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	1,257	1,257
Trade names
Indefinite-lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	121	122
Licenses
Indefinite-lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	52	52
Foreign currency translation adjustment
Indefinite-lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	(195)	(176)
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Amount	65	54
Accumulated Amortization	(18)	(15)
Net Amount	$ 47	$ 39
Weighted-Average Useful Life (in Years)	9 years	9 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 1,599	$ 1,532
Accumulated Amortization	(484)	(456)
Net Amount	$ 1,115	$ 1,076
Weighted-Average Useful Life (in Years)	18 years	18 years
Other
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 18	$ 17
Accumulated Amortization	(3)	(2)
Net Amount	$ 15	$ 15
Weighted-Average Useful Life (in Years)	8 years	8 years
Foreign currency translation adjustment
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ (160)	$ (149)
Accumulated Amortization	52	64
Net Amount	$ (108)	$ (85)

Goodwill and Acquired Intangi_6

Goodwill and Acquired Intangible Assets (Estimated Future Amortization Expense) (Details) $ in Millions	Jun. 30, 2019USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2019	$ 53
2020	105
2021	104
2022	101
2023	98
2024 and thereafter	716
Total	$ 1,177

Investments (Schedule of Invest

Investments (Schedule of Investments) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Trading securities	$ 251	$ 259
Available-for-sale investment securities	8	9
Financial investments, at fair value	259	268
Equity method investments	147	135
Equity securities	$ 68	$ 44

Investments (Narrative) (Detail

Investments (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended			3 Months Ended			6 Months Ended		12 Months Ended
	Mar. 31, 2019	Feb. 28, 2019	Mar. 31, 2015	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investments, Debt and Securities [Line Items]
Trading securities				$ 251			$ 251		$ 259
Cumulative unrealized gains							0		0
Net income from unconsolidated investees				10		$ 5	55	$ 7
OCC
Investments, Debt and Securities [Line Items]
Net income from unconsolidated investees									16
Committed equity contribution			$ 150
Capital contribution			$ 30
Annual dividend from shareholders percentage			50.00%
Annual dividend received									13	$ 10	$ 4
Proceeds from contributed capital		$ 44
OCC, Prior Period Results
Investments, Debt and Securities [Line Items]
Net income from unconsolidated investees	$ 36
OCC, Current Period Results
Investments, Debt and Securities [Line Items]
Net income from unconsolidated investees				9	$ 9
Foreign Government Debt Securities
Investments, Debt and Securities [Line Items]
Trading securities				$ 180			$ 180		$ 166

Deferred Revenue (Changes in De

Deferred Revenue (Changes in Deferred Revenue) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Change in Contract with Customer Liability [Roll Forward]
Beginning balance	$ 281
Deferred revenue billed in the current period, net of recognition	267
Revenue recognized that was included in the beginning of the period	(140)
Translation adjustment	(7)
Ending balance	401
Initial Listing Revenues
Change in Contract with Customer Liability [Roll Forward]
Beginning balance	66
Deferred revenue billed in the current period, net of recognition	18
Revenue recognized that was included in the beginning of the period	(16)
Translation adjustment	(2)
Ending balance	66
Annual Listings Revenues
Change in Contract with Customer Liability [Roll Forward]
Beginning balance	4
Deferred revenue billed in the current period, net of recognition	118
Revenue recognized that was included in the beginning of the period	(2)
Translation adjustment	0
Ending balance	120
Market Technology Revenues
Change in Contract with Customer Liability [Roll Forward]
Beginning balance	75
Deferred revenue billed in the current period, net of recognition	28
Revenue recognized that was included in the beginning of the period	(29)
Translation adjustment	(4)
Ending balance	70
Corporate Solutions Revenues
Change in Contract with Customer Liability [Roll Forward]
Beginning balance	36
Deferred revenue billed in the current period, net of recognition	30
Revenue recognized that was included in the beginning of the period	(28)
Translation adjustment	0
Ending balance	38
Information Services Revenues
Change in Contract with Customer Liability [Roll Forward]
Beginning balance	80
Deferred revenue billed in the current period, net of recognition	67
Revenue recognized that was included in the beginning of the period	(58)
Translation adjustment	0
Ending balance	89
Other
Change in Contract with Customer Liability [Roll Forward]
Beginning balance	20
Deferred revenue billed in the current period, net of recognition	6
Revenue recognized that was included in the beginning of the period	(7)
Translation adjustment	(1)
Ending balance	$ 18

Deferred Revenue (Estimated Def

Deferred Revenue (Estimated Deferred Revenue) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Fiscal year ended:
2019	$ 272
2020	87
2021	24
2022	10
2023	5
2024 and thereafter	3
Total	401	$ 281
Initial Listing Revenues
Fiscal year ended:
2019	12
2020	24
2021	13
2022	9
2023	5
2024 and thereafter	3
Total	66	66
Annual Listings Revenues
Fiscal year ended:
2019	120
2020	0
2021	0
2022	0
2023	0
2024 and thereafter	0
Total	120	4
Market Technology Revenues
Fiscal year ended:
2019	35
2020	27
2021	8
2022	0
2023	0
2024 and thereafter	0
Total	70	75
Corporate Solutions Revenues
Fiscal year ended:
2019	31
2020	7
2021	0
2022	0
2023	0
2024 and thereafter	0
Total	38	36
Information Services Revenues
Fiscal year ended:
2019	67
2020	22
2021	0
2022	0
2023	0
2024 and thereafter	0
Total	89	80
Other
Fiscal year ended:
2019	7
2020	7
2021	3
2022	1
2023	0
2024 and thereafter	0
Total	$ 18	$ 20

Debt Obligations (Changes in De

Debt Obligations (Changes in Debt Obligations) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2019	Apr. 30, 2019	Apr. 30, 2017	Jun. 30, 2016	May 31, 2016	May 31, 2014	Jun. 30, 2013
Changes In Short-Term Debt Obligations [Roll Forward]
Short-term debt - commercial paper beginning balance	$ 1,474,000,000
Additions	1,866,000,000
Payments, Accretion and Other	(2,873,000,000)
Short-term debt - commercial paper ending balance	467,000,000
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	2,357,000,000
Additions	680,000,000
Payments, Accretion and Other	(15,000,000)
Long-term debt obligations at end of period	3,022,000,000
Changes In Debt Obligations [Roll Forward]
Total debt obligations at beginning of period	3,831,000,000
Additions	2,546,000,000
Payments, Accretion and Other	(2,888,000,000)
Total debt obligations at end of period	$ 3,489,000,000
Senior Notes | 3.875% senior unsecured notes due June 7, 2021
Schedule of Debt [Line Items]
Stated rate	3.875%						3.875%
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	$ 686,000,000
Additions	0
Payments, Accretion and Other	(6,000,000)
Long-term debt obligations at end of period	$ 680,000,000
Senior Notes | 4.25% senior unsecured notes due June 1, 2024
Schedule of Debt [Line Items]
Stated rate	4.25%					4.25%
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	$ 497,000,000
Additions	0
Payments, Accretion and Other	0
Long-term debt obligations at end of period	$ 497,000,000
Senior Notes | 1.75% senior unsecured notes due May 19, 2023
Schedule of Debt [Line Items]
Stated rate	1.75%				1.75%
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	$ 682,000,000
Additions	0
Payments, Accretion and Other	5,000,000
Long-term debt obligations at end of period	$ 677,000,000
Senior Notes | 3.85% senior unsecured notes due June 30, 2026
Schedule of Debt [Line Items]
Stated rate	3.85%			3.85%
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	$ 496,000,000
Additions	0
Payments, Accretion and Other	1,000,000
Long-term debt obligations at end of period	$ 497,000,000
Senior Notes | 1.75% senior unsecured notes due March 28, 2029
Schedule of Debt [Line Items]
Stated rate	1.75%	1.75%
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	$ 0
Additions	665,000,000
Payments, Accretion and Other	(9,000,000)
Long-term debt obligations at end of period	674,000,000
Revolving Credit Facility | $1 billion senior unsecured revolving credit facility due April 25, 2022 (average interest rate of 5.60% for the period January 1, 2019 through June 30, 2019)
Schedule of Debt [Line Items]
Facility borrowing capacity	$ 1,000,000,000		$ 1,000,000,000
Interest rate	5.60%
Changes in Long-Term Debt Obligations [Roll Forward]
Long-term debt obligations at beginning of period	$ (4,000,000)
Additions	15,000,000
Payments, Accretion and Other	(14,000,000)
Long-term debt obligations at end of period	(3,000,000)
Commercial paper
Changes In Short-Term Debt Obligations [Roll Forward]
Short-term debt - commercial paper beginning balance	275,000,000
Additions	1,866,000,000
Payments, Accretion and Other	(1,674,000,000)
Short-term debt - commercial paper ending balance	467,000,000
Senior unsecured floating rate notes due March 22, 2019
Changes In Short-Term Debt Obligations [Roll Forward]
Short-term debt - commercial paper beginning balance	500,000,000
Additions	0
Payments, Accretion and Other	(500,000,000)
Short-term debt - commercial paper ending balance	0
5.55% senior unsecured notes repaid on May 1, 2019
Changes In Short-Term Debt Obligations [Roll Forward]
Short-term debt - commercial paper beginning balance	599,000,000
Additions	0
Payments, Accretion and Other	(599,000,000)
Short-term debt - commercial paper ending balance	0
$400 million senior unsecured term loan facility repaid on June 28, 2019 (average interest rate of 4.00% for the period January 1, 2019 through June 28, 2019)
Schedule of Debt [Line Items]
Facility borrowing capacity	$ 400,000,000
Interest rate	4.00%
Changes In Short-Term Debt Obligations [Roll Forward]
Short-term debt - commercial paper beginning balance	$ 100,000,000
Additions	0
Payments, Accretion and Other	(100,000,000)
Short-term debt - commercial paper ending balance	$ 0

Debt Obligations (Commercial Pa

Debt Obligations (Commercial Paper) (Details) - Commercial paper	6 Months Ended
	Jun. 30, 2019
Short-term Debt [Line Items]
Weighted average interest rate	2.64%
Minimum
Short-term Debt [Line Items]
Maturity period	13 days
Maximum
Short-term Debt [Line Items]
Maturity period	63 days
Weighted Average
Short-term Debt [Line Items]
Maturity period	29 days

Debt Obligations (Senior Unsecu

Debt Obligations (Senior Unsecured Notes) (Details)	6 Months Ended
	Jun. 30, 2019
Senior Notes | Senior Notes Excluding 2020 Notes
Debt Instrument [Line Items]
Aggregate principal amount purchased plus accrued and unpaid interest	101.00%

Debt Obligations (Senior Unse_2

Debt Obligations (Senior Unsecured Floating Rate Notes) (Details)	1 Months Ended
	Sep. 30, 2017
Senior unsecured floating rate notes due March 22, 2019 | Senior Notes | LIBOR
Debt Instrument [Line Items]
Spread on variable rate	0.39%

Debt Obligations (Early Extingu

Debt Obligations (Early Extinguishment of 5.55% Senior Unsecured Notes) (Details) - Senior Notes - USD ($) $ in Millions	1 Months Ended
	May 31, 2019	Jun. 30, 2019	Apr. 30, 2019	Jan. 31, 2019	Jan. 31, 2010
5.55% senior unsecured notes repaid on May 1, 2019
Debt Instrument [Line Items]
Stated rate		5.55%		5.55%	5.55%
Early extinguishment of senior notes	$ 11
1.75% senior unsecured notes due March 28, 2029
Debt Instrument [Line Items]
Stated rate		1.75%	1.75%

Debt Obligations (3.875% Senior

Debt Obligations (3.875% Senior Unsecured Notes) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2013
Debt Instrument [Line Items]
Decrease in carrying amount	$ 15
Senior Notes | 3.875% senior unsecured notes due June 7, 2021
Debt Instrument [Line Items]
Stated rate	3.875%	3.875%
Decrease in carrying amount	$ 6
Senior Notes | 3.875% senior unsecured notes due June 7, 2021 | Maximum
Debt Instrument [Line Items]
Maximum interest rate on debt instrument		5.875%

Debt Obligations (4.25% Senior

Debt Obligations (4.25% Senior Unsecured Notes) (Details) - Senior Notes - 4.25% senior unsecured notes due June 1, 2024	Jun. 30, 2019	May 31, 2014
Debt Instrument [Line Items]
Stated rate	4.25%	4.25%
Maximum
Debt Instrument [Line Items]
Maximum interest rate on debt instrument		6.25%

Debt Obligations (1.75% Senior

Debt Obligations (1.75% Senior Unsecured Notes Due 2023) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Apr. 30, 2019	May 31, 2016
Debt Instrument [Line Items]
Decrease in carrying amount	$ 15
Senior Notes | 1.75% senior unsecured notes due May 19, 2023
Debt Instrument [Line Items]
Stated rate	1.75%		1.75%
Decrease in carrying amount	$ (5)
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

Debt Obligations (3.85% Senior Unsecured Notes) (Details) - Senior Notes - 3.85% senior unsecured notes due June 30, 2026	Jun. 30, 2019	Jun. 30, 2016
Debt Instrument [Line Items]
Stated rate	3.85%	3.85%
Maximum
Debt Instrument [Line Items]
Maximum interest rate on debt instrument		5.85%

Debt Obligations Debt Obligatio

Debt Obligations Debt Obligations (1.75% Senior Unsecured Notes Due 2029) (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended
	Apr. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Jan. 31, 2019	Jan. 31, 2010
Debt Instrument [Line Items]
Proceeds from issuances of long-term debt, net of issuance costs		$ 680	$ 0
Increase in carrying amount		$ 15
Senior Notes | 1.75% senior unsecured notes due March 28, 2029
Debt Instrument [Line Items]
Stated rate	1.75%	1.75%
Increase in carrying amount		$ 9
Senior Notes | 5.55% senior unsecured notes repaid on May 1, 2019
Debt Instrument [Line Items]
Stated rate		5.55%		5.55%	5.55%
Maximum | Senior Notes | 1.75% senior unsecured notes due March 28, 2029
Debt Instrument [Line Items]
Maximum interest rate on debt instrument	3.75%
Proceeds from issuances of long-term debt, net of issuance costs	$ 665

Debt Obligations (2017 Credit F

Debt Obligations (2017 Credit Facility) (Details) - Revolving Credit Facility - $1 billion senior unsecured revolving credit facility due April 25, 2022 (average interest rate of 5.60% for the period January 1, 2019 through June 30, 2019) - USD ($)	1 Months Ended	6 Months Ended
	Apr. 30, 2017	Jun. 30, 2019
Debt Instrument [Line Items]
Credit facility, borrowing capacity	$ 1,000,000,000	$ 1,000,000,000
Credit facility term	5 years
Line of credit facility, fair value of amount outstanding		0
Unamortized debt issuance expense		3,000,000
Remaining amount available		531,000,000
Option to increase available aggregate amount		500,000,000
Commercial Paper And Letter Of Credit
Debt Instrument [Line Items]
Credit facility, remaining residual borrowing capacity		$ 469,000,000
Minimum
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage		0.125%
Maximum
Debt Instrument [Line Items]
Line of credit facility, commitment fee percentage		0.40%

Debt Obligations (Other Credit

Debt Obligations (Other Credit Facilities) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Commercial Paper And Letter Of Credit | Clearinghouse Credit Facilities
Debt Instrument [Line Items]
Remaining amount available	$ 211	$ 220

Retirement Plans (Narrative) (D

Retirement Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Retirement Benefits [Abstract]
Employer contribution match, percent match			100.00%	100.00%
Employer contribution match, percentage of employee contribution			6.00%	6.00%
Defined contributions plan expense	$ 3	$ 3	$ 6	$ 7
Cost or expenses included in compensation and benefit expense	$ 5	$ 5	$ 10	$ 11

Share-Based Compensation (Narra

Share-Based Compensation (Narrative) (Details) $ / shares in Units, $ in Millions	Jan. 30, 2018	Jan. 31, 2017$ / sharesshares	Jun. 30, 2019USD ($)$ / sharespeer_groupshares	Jun. 30, 2018USD ($)$ / sharesshares	Jun. 30, 2019USD ($)program$ / sharespeer_groupshares	Jun. 30, 2018USD ($)$ / sharesshares	Jun. 28, 2019$ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares reserved for future issuance (in shares)			10,300,000		10,300,000
Stock options exercised in period (in shares)			44,742	53,805	53,408	88,000
Net cash proceeds from the exercise of stock options | $			$ 1	$ 1	$ 1	$ 2
Share price (in dollars per share) | $ / shares							$ 96.17
Stock options, exercisable (in shares)			305,927	300,000	305,927	300,000
Options exercisable, weighted average exercise price (in dollars per share) | $ / shares			$ 48.87	$ 35.98	$ 48.87	$ 35.98
Total pre-tax intrinsic value of stock options exercised | $			$ 3	$ 4	$ 4	$ 6
Share-based compensation expense before income taxes | $			$ 20	$ 18	$ 36	$ 33
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Discount from market price				15.00%	15.00%	15.00%
Common stock shares reserved for future issuance (in shares)			1,700,000		1,700,000
Maximum percentage of shares purchased from annual compensation					10.00%
Discount given to employees					15.00%
Share-based compensation expense before income taxes | $					$ 2	$ 2
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost | $			$ 73		$ 73
Weighted-average period unrecognized compensation cost is expected to be recognized, in years					1 year 10 months 24 days
PSUs | One-Year Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost | $			17		$ 17
Weighted-average period unrecognized compensation cost is expected to be recognized, in years					1 year 7 months 6 days
Performance period					1 year
Percentage of target amount granted, minimum					0.00%
Percentage of target amount granted, maximum					150.00%
Vesting period					3 years
Additional units granted above target (in shares)					51,914
PSUs | Three-Year Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost | $			$ 45		$ 45
Weighted-average period unrecognized compensation cost is expected to be recognized, in years					1 year 7 months 6 days
Performance period					3 years
Additional units granted above target (in shares)					99,622
Number of peer groups | peer_group			2		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			$ 89	$ 86.24	$ 89	$ 86.24
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 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 awards granted (in shares)					0
Weighted-average grant date fair value (in dollars per share) | $ / shares		$ 66.68
Expected life (in years)		6 years
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
Second Anniversary | Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage					25.00%
Second Anniversary | Employee Stock Option | CEO
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	33.33%
Third Anniversary | Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage					25.00%
Fourth Anniversary | Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage					50.00%

Share-Based Compensation (Summa

Share-Based Compensation (Summary of Share-Based Compensation Expense) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Payment Arrangement [Abstract]
Share-based compensation expense before income taxes	$ 20	$ 18	$ 36	$ 33
Income tax benefit	(6)	(5)	(10)	(9)
Share-based compensation expense after income taxes	$ 14	$ 13	$ 26	$ 24

Share-Based Compensation (Sum_2

Share-Based Compensation (Summary of Restricted Stock Activity) (Details) - Restricted stock	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Number of Awards
Unvested balances at beginning of period (in shares) | shares	1,583,375
Granted (in shares) | shares	576,036
Vested (in shares) | shares	(477,052)
Forfeited (in shares) | shares	(102,894)
Unvested balances at end of period (in shares) | shares	1,579,465
Weighted-Average Grant Date Fair Value
Unvested balances at beginning of period (in dollars per share) | $ / shares	$ 68.62
Granted (in dollars per share) | $ / shares	84.46
Vested (in dollars per share) | $ / shares	59.15
Forfeited (in dollars per share) | $ / shares	72.16
Unvested balances at end of period (in dollars per share) | $ / shares	$ 77

Share-Based Compensation (Sched

Share-Based Compensation (Schedule of Weighted- Average Assumptions Used to Determine Weighted-Average Fair Values) (Details) - $ / shares	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 28, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date share price (in dollars per share)			$ 96.17
PSUs | Three-Year Program
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average risk free interest rate	2.26%	2.36%
Expected volatility	16.50%	18.70%
Weighted-average grant date share price (in dollars per share)	$ 89	$ 86.24
Weighted-average fair value at grant date (in dollars per share)	$ 97.65	$ 116.86

Share-Based Compensation (Sum_3

Share-Based Compensation (Summary of PSU Activity) (Details) - PSUs	6 Months Ended
	Jun. 30, 2019$ / sharesshares
One-Year Program
Number of Awards
Unvested balances at beginning of period (in shares) | shares	314,231
Granted (in shares) | shares	179,599
Vested (in shares) | shares	(8,207)
Forfeited (in shares) | shares	(20,958)
Unvested balances at end of period (in shares) | shares	464,665
Weighted-Average Grant Date Fair Value
Unvested balances at beginning of period (in dollars per share) | $ / shares	$ 74.01
Granted (in dollars per share) | $ / shares	83.56
Vested (in dollars per share) | $ / shares	64.91
Forfeited (in dollars per share) | $ / shares	74.86
Unvested balances at end of period (in dollars per share) | $ / shares	$ 77.82
Three-Year Program
Number of Awards
Unvested balances at beginning of period (in shares) | shares	837,750
Granted (in shares) | shares	397,553
Vested (in shares) | shares	(431,751)
Forfeited (in shares) | shares	(6,101)
Unvested balances at end of period (in shares) | shares	797,451
Weighted-Average Grant Date Fair Value
Unvested balances at beginning of period (in dollars per share) | $ / shares	$ 96.57
Granted (in dollars per share) | $ / shares	96.55
Vested (in dollars per share) | $ / shares	93.25
Forfeited (in dollars per share) | $ / shares	103.29
Unvested balances at end of period (in dollars per share) | $ / shares	$ 98.31

Share-Based Compensation (Sum_4

Share-Based Compensation (Summary of Stock Options Valuation Assumptions) (Details) - Employee Stock Option	1 Months Ended
	Jan. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected life (in years)	6 years
Weighted-average risk free interest rate	2.10%
Expected volatility	25.60%
Dividend yield	1.92%

Share-Based Compensation (Sum_5

Share-Based Compensation (Summary of Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Number of Stock Options
Outstanding at Beginning of period (in shares)			447,716
Exercised (in shares)	(44,742)	(53,805)	(53,408)	(88,000)
Forfeited (in shares)			(25)
Outstanding at End of period (in shares)	394,283		394,283		447,716
Stock options, exercisable (in shares)	305,927	300,000	305,927	300,000
Weighted-Average Exercise Price
Outstanding at Beginning of period (in dollars per share)			$ 49.25
Exercised (in dollars per share)			21.02
Forfeited (in dollars per share)			20.10
Outstanding at End of period (in dollars per share)	$ 52.91		52.91		$ 49.25
Options exercisable, weighted average exercise price (in dollars per share)	$ 48.87	$ 35.98	$ 48.87	$ 35.98
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding beginning balance, Weighted-Average Remaining Contractual Term (in years)			5 years 6 months 21 days		5 years 6 months 3 days
Outstanding ending balance, Weighted-Average Remaining Contractual Term (in years)			4 years 11 months 26 days
Outstanding beginning balance, Aggregate Intrinsic Value	$ 17		$ 17		$ 14
Outstanding ending balance, Aggregate Intrinsic Value	$ 14		$ 14

Nasdaq Stockholders' Equity (Na

Nasdaq Stockholders' Equity (Narrative) (Details)	Apr. 23, 2019USD ($)$ / shares	Jan. 29, 2019USD ($)$ / shares	Jul. 31, 2019USD ($)$ / shares	Jun. 30, 2019USD ($)vote$ / sharesshares	Jun. 30, 2018$ / shares	Jun. 30, 2019USD ($)vote$ / sharesshares	Jun. 30, 2018$ / sharesshares	Dec. 31, 2018shares	Jan. 31, 2018USD ($)
Stockholders Equity [Line Items]
Common stock, shares authorized (in shares)				300,000,000		300,000,000		300,000,000
Common stock, shares issued (in shares)				171,288,122		171,288,122		170,709,425
Common stock, shares outstanding (in shares)				165,389,235		165,389,235		165,165,104
Common stock (in votes per share) | vote				1		1
Common stock holder voting rights, maximum percentage of the then-outstanding shares of Nasdaq common stock				5.00%		5.00%
Common stock in treasury (in shares)				5,898,887		5,898,887		5,544,321
Share repurchase program additional amount authorized | $									$ 500,000,000
Share repurchase program, authorized amount | $									$ 726,000,000
Remaining authorized share repurchase amounts under repurchase program | $				$ 282,000,000		$ 282,000,000
Number of shares of common stock repurchased (in shares)						538,449	3,929,520
Preferred stock, shares authorized (in shares)				30,000,000		30,000,000
Preferred stock par value (in dollars per share) | $ / shares				$ 0.01		$ 0.01
Payments of dividends | $						$ 150,000,000
Cash dividends declared per common share (in dollars per share) | $ / shares	$ 0.47	$ 0.44		$ 0.47	$ 0	$ 0.91	$ 0.82
Dividends declared | $	$ 77,000,000	$ 73,000,000				$ 150,000,000
Other Repurchases of Common Stock
Stockholders Equity [Line Items]
Number of shares of common stock repurchased (in shares)						354,566
Series A Preferred Stock
Stockholders Equity [Line Items]
Preferred stock, series A preferred stock, shares issued (in shares)				0		0		0
Preferred stock, series A preferred stock, shares outstanding (in shares)				0		0		0
Subsequent Event
Stockholders Equity [Line Items]
Cash dividends declared per common share (in dollars per share) | $ / shares			$ 0.47
Dividends declared | $			$ 78,000,000

Nasdaq Stockholders' Equity (Co

Nasdaq Stockholders' Equity (Common Stock in Treasury) (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Equity [Abstract]
Number of shares of common stock repurchased (in shares)	538,449	3,929,520
Average price paid per share (in dollars per share)	$ 92.84	$ 86.58
Total purchase price	$ 50	$ 340

Nasdaq Stockholders' Equity (Sc

Nasdaq Stockholders' Equity (Schedule of Dividends Declared) (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 23, 2019	Jan. 29, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Equity [Abstract]
Dividend Per Common Share	$ 0.47	$ 0.44	$ 0.47	$ 0	$ 0.91	$ 0.82
Total Amount Paid	$ 77	$ 73			$ 150

Earnings Per Share (Summary of

Earnings Per Share (Summary of Computation of Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator:
Net income attributable to common shareholders	$ 174	$ 162	$ 421	$ 339
Denominator:
Weighted-average common shares outstanding for basic earnings per share (in shares)	165,596,174	165,748,107	165,470,767	166,331,583
Weighted-average effect of dilutive securities:
Employee equity awards (in shares)	1,445,245	1,651,497	1,564,016	1,812,437
Weighted-average common shares outstanding for diluted earnings per share (in shares)	167,041,419	167,399,604	167,034,783	168,144,020
Basic and diluted earnings per share:
Basic earnings per share (in dollars per share)	$ 1.05	$ 0.98	$ 2.54	$ 2.04
Diluted earnings per share (in dollars per share)	$ 1.04	$ 0.97	$ 2.52	$ 2.02

Fair Value of Financial Instr_3

Fair Value of Financial Instruments (Schedule of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Assets at Fair Value
Financial investments, at fair value	$ 259	$ 268
Fair Value, Measurements, Recurring
Assets at Fair Value
Financial investments, at fair value	259	268
Default fund and margin deposit investments	1,496	1,649
Total assets at fair value	1,755	1,917
Liabilities at Fair Value
Other financial instruments		112
Total liabilities at fair value		112
Fair Value, Measurements, Recurring | Level 1
Assets at Fair Value
Financial investments, at fair value	164	133
Default fund and margin deposit investments	234	327
Total assets at fair value	398	460
Liabilities at Fair Value
Other financial instruments		0
Total liabilities at fair value		0
Fair Value, Measurements, Recurring | Level 2
Assets at Fair Value
Financial investments, at fair value	95	135
Default fund and margin deposit investments	1,262	1,322
Total assets at fair value	1,357	1,457
Liabilities at Fair Value
Other financial instruments		112
Total liabilities at fair value		112
Fair Value, Measurements, Recurring | Level 3
Assets at Fair Value
Financial investments, at fair value	0	0
Default fund and margin deposit investments	0	0
Total assets at fair value	$ 0	0
Liabilities at Fair Value
Other financial instruments		0
Total liabilities at fair value		$ 0

Fair Value of Financial Instr_4

Fair Value of Financial Instruments (Narrative) (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	$ 251,000,000	$ 259,000,000
Liability due to market default	0
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other financial instruments		112,000,000
Collateral due to market default		112,000,000
Liability due to market default		112,000,000
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other financial instruments		112,000,000
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	3,700,000,000	3,900,000,000
Foreign Government Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading securities	$ 180,000,000	$ 166,000,000

Clearing Operations (Narrative)

Clearing Operations (Narrative) (Details)	1 Months Ended		6 Months Ended
	Dec. 31, 2018USD ($)	Sep. 30, 2018USD ($)	Jun. 30, 2019USD ($)fundcontract	Jun. 30, 2018USD ($)contract
Clearing Operations [Line Items]
Number of member sponsored default funds | fund			4
Loss due to commodities market default		$ 133,000,000
Loss due to commodities market default allocated to junior capital		$ 8,000,000
Capital relief program expense	$ 23,000,000
Liability due to market default			$ 0
Default funds and margin deposits	4,742,000,000		3,161,000,000
Default fund contributions			561,000,000
Committed capital	268,000,000		259,000,000
Liability Waterfall
Clearing Operations [Line Items]
Junior capital, cash deposits and pledged assets			34,000,000
Senior capital, cash deposits and pledged assets			22,000,000
Committed capital			96,000,000
Utilize as capital resources
Clearing Operations [Line Items]
Default fund contributions			473,000,000
Utilize as member posted surplus balance
Clearing Operations [Line Items]
Default fund contributions			88,000,000
Nasdaq Clearing
Clearing Operations [Line Items]
Default fund cash contributions invested in highly rated government debt securities			$ 973,000,000
Maturity period of time deposits			90 days
Committed capital			$ 152,000,000
Power of assessment of the clearing member's contribution to the financial markets and commodities markets default funds			100.00%
Contract value of resale and repurchase agreements			$ 3,800,000,000	$ 3,400,000,000
Total number of derivative contracts cleared | contract			3,787,315	4,498,651
Nasdaq Clearing | Reverse Repurchase Agreements
Clearing Operations [Line Items]
Default funds and margin deposits			$ 523,000,000
Minimum
Clearing Operations [Line Items]
Reverse purchase agreements, maturity range			3 days
Maximum
Clearing Operations [Line Items]
Reverse purchase agreements, maturity range			18 days
Fair Value, Measurements, Recurring
Clearing Operations [Line Items]
Liability due to market default	112,000,000
Collateral due to market default	112,000,000
Committed capital	$ 268,000,000		$ 259,000,000

Clearing Operations (Schedule o

Clearing Operations (Schedule of Clearing Member Default Fund Contributions And Margin Deposits) (Details) $ in Millions	Jun. 30, 2019USD ($)
Clearing Operations [Line Items]
Default fund contributions	$ 561
Margin deposits	6,196
Total	6,757
Cash Contributions
Clearing Operations [Line Items]
Default fund contributions	438
Margin deposits	2,723
Total	3,161
Non-Cash Contributions
Clearing Operations [Line Items]
Default fund contributions	123
Margin deposits	3,473
Total	$ 3,596

Clearing Operations (Schedule_2

Clearing Operations (Schedule of Derivative Contracts) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)TWhcontract	Jun. 30, 2018TWhcontract
Clearing Operations [Line Items]
Market value of derivative contracts | $	$ 1,517
Total number of cleared contracts (in shares) | contract	48,186,110	49,030,572
Total volume in cleared power, in Terawatt hours (TWh) | TWh	420	577
Commodity and seafood options, futures and forwards
Clearing Operations [Line Items]
Market value of derivative contracts | $	$ 411
Total number of cleared contracts (in shares) | contract	267,006	1,162,716
Fixed-income options and futures
Clearing Operations [Line Items]
Market value of derivative contracts | $	$ 889
Total number of cleared contracts (in shares) | contract	11,565,386	11,286,397
Stock options and futures
Clearing Operations [Line Items]
Market value of derivative contracts | $	$ 133
Total number of cleared contracts (in shares) | contract	12,476,329	11,940,062
Index options and futures
Clearing Operations [Line Items]
Market value of derivative contracts | $	$ 84
Total number of cleared contracts (in shares) | contract	23,877,389	24,641,397

Income Taxes (Components of Inc

Income Taxes (Components of Income Tax Provision) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income tax provision	$ 65	$ 126	$ 131	$ 188
Percent change in income tax provision	(48.40%)		(30.30%)
Effective tax rate	27.20%	43.80%	23.70%	35.70%

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Mar. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Line Items]
Payments for tax settlements		$ 45
Foreign Tax Authority | Sweden
Income Tax Disclosure [Line Items]
Tax expense (benefits) associated with foreign tax agency				$ (56)	$ 41
Tax expense (benefits), per diluted share (in dollars per share)					$ 0.24
Quarterly recurring tax expense	$ 1
Accumulated Other Comprehensive Loss | Accounting Standards Update 2018-02
Income Tax Disclosure [Line Items]
Reclassification from AOCI, tax amount			$ 142
Employee Benefit Plan Adjustment Gains and Losses | Accounting Standards Update 2018-02
Income Tax Disclosure [Line Items]
Reclassification from AOCI, tax amount			135
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent | Accounting Standards Update 2018-02
Income Tax Disclosure [Line Items]
Reclassification from AOCI, tax amount			$ 7

Commitments, Contingencies an_2

Commitments, Contingencies and Guarantees (Details)	Sep. 02, 2014exchange	Jun. 30, 2019USD ($)shares	Dec. 31, 2018USD ($)	Oct. 31, 2018USD ($)
Commitments and Contingencies Disclosure [Line Items]
Financial guarantees obtained		$ 11,000,000	$ 12,000,000
National exchanges named as defendants | exchange	7
Estimate of possible legal fees				$ 1,000,000
eSpeed
Commitments and Contingencies Disclosure [Line Items]
Contingent future issuance of common stock (in shares) | shares		992,247
Revenue required to trigger annual issuance of Nasdaq common stock		$ 25,000,000
Escrow Agreement
Commitments and Contingencies Disclosure [Line Items]
Contingency, accrual		12,000,000
ICBC
Commitments and Contingencies Disclosure [Line Items]
Margin deposits contributed to brokers		15,000,000
Clearinghouse Credit Facilities
Commitments and Contingencies Disclosure [Line Items]
Credit facility, available liquidity		$ 211,000,000	$ 220,000,000

Business Segments (Narrative) (

Business Segments (Narrative) (Details)	6 Months Ended
	Jun. 30, 2019segment
Segment Reporting [Abstract]
Number of operating segments	4

Business Segments (Schedule of

Business Segments (Schedule of Operating Segments) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Total revenues	$ 1,061	$ 1,027	$ 2,100	$ 2,178
Transaction-based expenses	(438)	(412)	(843)	(897)
Revenues less transaction-based expenses	623	615	1,257	1,281
Operating income (loss)	256	269	531	541
Operating Segments | Market Services
Segment Reporting Information [Line Items]
Total revenues	665	649	1,304	1,384
Transaction-based expenses	(438)	(412)	(843)	(897)
Revenues less transaction-based expenses	227	237	461	487
Operating income (loss)	127	134	263	281
Operating Segments | Corporate Services
Segment Reporting Information [Line Items]
Total revenues	123	120	243	243
Transaction-based expenses	0	0	0	0
Revenues less transaction-based expenses	123	120	243	243
Operating income (loss)	44	34	87	76
Operating Segments | Information Services
Segment Reporting Information [Line Items]
Total revenues	194	175	387	348
Transaction-based expenses	0	0	0	0
Revenues less transaction-based expenses	194	175	387	348
Operating income (loss)	122	112	246	225
Operating Segments | Market Technology
Segment Reporting Information [Line Items]
Total revenues	79	66	156	126
Transaction-based expenses	0	0	0	0
Revenues less transaction-based expenses	79	66	156	126
Operating income (loss)	8	9	15	11
Corporate Items
Segment Reporting Information [Line Items]
Total revenues	0	17	10	77
Transaction-based expenses	0	0	0	0
Revenues less transaction-based expenses	0	17	10	77
Operating income (loss)	$ (45)	$ (20)	$ (80)	$ (52)

Business Segments (Corporate It

Business Segments (Corporate Items) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Revenues - divested businesses	$ 1,061	$ 1,027	$ 2,100	$ 2,178
Expenses:
Amortization expense of acquired intangible assets	26	28	51	56
Merger and strategic initiatives expense	5	(10)	14	0
Extinguishment of debt			11	0
Operating income	256	269	531	541
Corporate Items
Segment Reporting Information [Line Items]
Revenues - divested businesses	0	17	10	77
Expenses:
Amortization expense of acquired intangible assets	26	28	51	56
Merger and strategic initiatives expense	5	(10)	14	0
Extinguishment of debt	(11)	0	(11)	0
Expenses - divested businesses	0	16	8	67
Other	3	3	6	6
Total expenses	45	37	90	129
Operating income	$ (45)	$ (20)	$ (80)	$ (52)