Nasdaq Stockholders' Equity (Common Stock in Treasury) (Details) $ / shares in Units, $ in Millions	3 Months Ended
Mar. 31, 2020 USD ($) $ / shares shares
Equity [Abstract]
Number of shares of common stock repurchased (in shares) \| shares	1,182,114
Average price paid per share (in dollars per share) \| $ / shares	$ 103.17
Share repurchase program \| $	$ 122

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the par value method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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