Related Party Transactions (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions			1 Months Ended	3 Months Ended		12 Months Ended
	Jul. 31, 2014	Jun. 25, 2014	Dec. 31, 2015	Jun. 30, 2014	Dec. 31, 2013	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jun. 30, 2013
Related Party Transaction [Line Items]
Non-cash impairment charge on long-lived assets to be disposed					$ 36
Total number of shares purchased (in shares)			0.3
Total cash utilized			$ 26			$ 1,097	$ 1,002	$ 346
Average price paid per share (in dollars per share)			$ 98.98			$ 113.36	$ 99.00	$ 79.06
Harold W. McGraw III
Related Party Transaction [Line Items]
Total number of shares purchased (in shares)		0.5
Repurchase discount		0.35%
Total cash utilized		$ 41
Average price paid per share (in dollars per share)		$ 82.66
CME Group [Member] | S&P/DJ Indices [Member]
Related Party Transaction [Line Items]
Revenues earned under license agreement						$ 76	$ 63	$ 52
Noncontrolling interest ownership by noncontrolling owners									27.00%
Disposal Group, Disposed of by Sale, Not Discontinued Operations
Related Party Transaction [Line Items]
Non-cash impairment charge on long-lived assets to be disposed				$ 6
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Harold W. McGraw III
Related Party Transaction [Line Items]
Amount of transaction with related party	$ 20