Aggregate dividends declared during the period for each share of common stock outstanding.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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- Definition

Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Nasdaq Stockholders' Equity (Schedule of Dividends Declared) (Details) - USD ($) $ / shares in Units, $ in Millions					1 Months Ended	12 Months Ended
	Oct. 24, 2018	Jul. 24, 2018	Mar. 26, 2018	Jan. 30, 2018	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Dividends Payable [Line Items]
Dividend per common share (in dollars per share)		$ 0.44	$ 0.44	$ 0.38	$ 0.44	$ 1.7	$ 1.46	$ 1.21
Total Amount		$ 72	$ 73	$ 63		$ 280	$ 243	$ 200
Dividend Declaration Date Fourth Quarter
Dividends Payable [Line Items]
Dividend per common share (in dollars per share)	$ 0.44
Total Amount	$ 72