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Nasdaq Stockholders' Equity (Common Stock in Treasury) (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Equity [Abstract]      
Number of shares of common stock repurchased (in shares) 1,547,778 7,191,685  
Average per share price of repurchased stock (in dollars per share) $ 64.42 $ 52.44  
Total purchase price (in millions) $ 100 $ 377 $ 178