Basis of Presentation and Principles of Consolidation (Policies)	3 Months Ended
Mar. 31, 2020
Accounting Policies [Abstract]
Recently Adopted Accounting Standard	Recently Adopted Accounting Standard In June 2016, the FASB issued ASU 2016-13, “Measurement of Credit Losses on Financial Instruments.” This standard changes the impairment model for certain financial instruments. The new model is a forward looking expected loss model and applies 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 trade receivables. For available-for-sale debt securities with unrealized losses, credit losses are measured in a manner similar to previous accounting, except that the losses are recognized as allowances rather than reductions in the amortized cost of the securities. We adopted this standard on January 1, 2020 using the modified retrospective transition method. We recorded a $12 million non-cash cumulative effect adjustment to retained earnings on our opening Condensed Consolidated Balance Sheets as of January 1, 2020. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. We expect the impact of the adoption of the new standard to be immaterial to our net income on an on-going basis. At the date of adoption, the adjustment impacted by the standard related primarily to an adjustment to trade receivables. We took into consideration all financial instruments held at the date of adoption which were impacted by the standard, including reverse repurchase agreements and commercial paper, and estimated the risk of loss to be immaterial. Therefore, no adjustment was recorded for these instruments. In accordance with the new standard, Nasdaq must recognize an allowance when a receivable or contract asset is established, regardless of whether there has been an incurred loss. Our receivables are concentrated with our member firms, market data distributors, listed companies and corporate solutions and market technology customers. In order to assess the appropriate allowance as of January 1, 2020, we disaggregated our trade receivables by business unit and the aging of receivables. We concluded that historical loss information is a reasonable starting point on which to determine expected credit losses for trade receivables held at the date of adoption as the composition of our trade receivables at adoption of the standard is materially consistent with that used in developing the historical loss percentages for each business unit. In order to incorporate our expectation of credit losses over the life of our receivables, we considered corporate default rate averages over an extended period as compared to the period covered by our historical loss data and included an adjustment to historical loss percentages for current conditions and expected future conditions at the date of adoption. The allowance for losses is reviewed monthly and adjustments may be required if economic conditions at the measurement date reflect stronger or weaker economic performance than the historical data implies. If circumstances change (i.e., higher than expected defaults or an unexpected material adverse change in a major customer’s ability to pay), our estimates of recoverability could be reduced by a material amount. When we deem all or a portion of a receivable uncollectible the allowance for losses is reduced by the amount being written off. Any change in the allowance is included in general, administrative and other expense in the Condensed Consolidated Statements of Income. Receivables are shown net of the allowance for losses. The total allowance netted against receivables in the Condensed Consolidated Balance Sheets was $21 million as of March 31, 2020 and $9 million as of December 31, 2019.
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 6, “Investments,” for further discussion of our equity method investments.
Principles of 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.
Reclassification	Certain prior year amounts have been reclassified to conform to the current year presentation.
Use of Estimates	In preparing our condensed consolidated financial statements, we make assumptions, judgments and estimates that can have a significant impact on our revenue, operating income and net income, as well as on the value of certain assets and liabilities in our condensed consolidated balance sheets. At least quarterly, we evaluate our assumptions, judgments and estimates, and make changes as deemed necessary. Nasdaq considered the impact of COVID-19 on the assumptions and estimates used in evaluating our assets and liabilities, including but not limited to our goodwill, intangible assets, equity method investments, equity securities and allowance for losses on accounts receivable. We determined that there were no material adverse impacts on our first quarter 2020 results of operations. In addition, there were no material impairment charges recorded for the three months ended March 31, 2020. These estimates may change as new events occur and additional information is obtained. Actual results could differ from these estimates under different assumptions or conditions.
Subsequent Events	We have evaluated subsequent events through the issuance date of this Quarterly Report on Form 10-Q. For discussion of financing actions subsequent to March 31, 2020, see “3.25% Senior Unsecured Notes Due 2050,” and “2017 Credit Facility,” of Note 8, “Debt Obligations.”

Basis of Presentation and Principles of Consolidation (Policies)

3 Months Ended

Mar. 31, 2020

In June 2016, the FASB issued ASU 2016-13, “Measurement of Credit Losses on Financial Instruments.” This standard changes the impairment model for certain financial instruments. The new model is a forward looking expected loss model and applies 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 trade receivables. For available-for-sale debt securities with unrealized losses, credit losses are measured in a manner similar to previous accounting, except that the losses are recognized as allowances rather than reductions in the amortized cost of the securities.

We adopted this standard on January 1, 2020 using the modified retrospective transition method. We recorded a $12 million non-cash cumulative effect adjustment to retained earnings on our opening Condensed Consolidated Balance Sheets as of January 1, 2020.

The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. We expect the impact of the adoption of the new standard to be immaterial to our net income on an on-going basis.

At the date of adoption, the adjustment impacted by the standard related primarily to an adjustment to trade receivables. We took into consideration all financial instruments held at the date of adoption which were impacted by the standard, including reverse repurchase agreements and commercial paper, and estimated the risk of loss to be immaterial. Therefore, no adjustment was recorded for these instruments.

In accordance with the new standard, Nasdaq must recognize an allowance when a receivable or contract asset is established, regardless of whether there has been an incurred loss. Our receivables are concentrated with our member firms, market data distributors, listed companies and corporate solutions and market technology customers.

In order to assess the appropriate allowance as of January 1, 2020, we disaggregated our trade receivables by business unit and the aging of receivables. We concluded that historical loss information is a reasonable starting point on which to determine expected credit losses for trade receivables held at the date of adoption as the composition of our trade receivables at adoption of the standard is materially consistent with that used in developing the historical loss percentages for each business unit. In order to incorporate our expectation of credit losses over the life of our receivables, we considered corporate default rate averages over an extended period as compared to the period covered by our historical loss data and included an adjustment to historical loss percentages for current conditions and expected future conditions at the date of adoption.

The allowance for losses is reviewed monthly and adjustments may be required if economic conditions at the measurement date reflect stronger or weaker economic performance than the historical data implies. If circumstances change (i.e., higher than expected defaults or an unexpected material adverse change in a major customer’s ability to pay), our estimates of recoverability could be reduced by a material amount. When we deem all or a portion of a receivable uncollectible the allowance for losses is reduced by the amount being written off. Any change in the allowance is included in general, administrative and other expense in the Condensed Consolidated Statements of Income.

Receivables are shown net of the allowance for losses. The total allowance netted against receivables in the Condensed Consolidated Balance Sheets was $21 million as of March 31, 2020 and $9 million as of December 31, 2019.

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 6, “Investments,” for further discussion of our equity method investments.

Principles of 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.

Reclassification

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

Use of Estimates

In preparing our condensed consolidated financial statements, we make assumptions, judgments and estimates that can have a significant impact on our revenue, operating income and net income, as well as on the value of certain assets and liabilities in our condensed consolidated balance sheets. At least quarterly, we evaluate our assumptions, judgments and estimates, and make changes as deemed necessary.

Nasdaq considered the impact of COVID-19 on the assumptions and estimates used in evaluating our assets and liabilities, including but not limited to our goodwill, intangible assets, equity method investments, equity securities and allowance for losses on accounts receivable. We determined that there were no material adverse impacts on our first quarter 2020 results of operations. In addition, there were no material impairment charges recorded for the three months ended March 31, 2020. These estimates may change as new events occur and additional information is obtained. Actual results could differ from these estimates under different assumptions or conditions.

Subsequent Events

We have evaluated subsequent events through the issuance date of this Quarterly Report on Form 10-Q. For discussion of financing actions subsequent to March 31, 2020, see “3.25% Senior Unsecured Notes Due 2050,” and “2017 Credit Facility,” of Note 8, “Debt Obligations.”