Related Party Transactions (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended	0 Months Ended			3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jun. 30, 2014 Other (Income) Loss [Member]	Jul. 31, 2014 Mr. Terry McGraw [Member]	Jun. 25, 2014 Mr. Terry McGraw [Member]	Jun. 25, 2014 Harold W. McGraw III [Member]	Sep. 30, 2014 CME Group S&P DJ Indices	Sep. 30, 2014 CME Group S&P DJ Indices
Related Party Transaction [Line Items]
Transaction amount						$ 20
Non-cash impairment charge					6
Total number of shares purchased (in shares)	0	6.4	4.4	15.0			0.5	0.5
Repurchase discount							0.35%	0.35%
Total cash utilized	0	350	352	850			41
Average price paid per share (in dollars per share)	$ 0.00	$ 61.42	$ 79.06	$ 61.42			$ 82.66
Revenues earned under license agreement									$ 13	$ 38
Noncontrolling interest ownership by noncontrolling owners									27.00%	27.00%