Capital Stock (Narrative) (Details) (USD $)
In Millions, except Share data, unless otherwise specified |
12 Months Ended | 12 Months Ended | 12 Months Ended | 1 Months Ended | ||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2013
|
Dec. 31, 2013
Class A Common Stock (Shares) [Member]
|
Dec. 31, 2012
Class A Common Stock (Shares) [Member]
|
Dec. 31, 2013
Class B Common Stock (Shares)
|
Dec. 31, 2012
Class B Common Stock (Shares)
|
Dec. 31, 2013
Class B Common Stock, Class B1 [Member]
directors
|
Dec. 31, 2013
Class B Common Stock, Class B2 [Member]
directors
|
Dec. 31, 2013
Class B Common Stock, Class B3 [Member]
directors
|
Dec. 31, 2013
Class B common stock, Class B1, B2, B3 [Member]
directors
|
Dec. 31, 2013
Core Rights [Member]
Class B Common Stock, Class B1 [Member]
|
Dec. 31, 2013
Core Rights [Member]
Class B Common Stock, Class B2 [Member]
|
Dec. 31, 2013
Core Rights [Member]
Class B Common Stock, Class B3 [Member]
|
Dec. 31, 2013
Core Rights [Member]
Class B Common Stock, Class B4 [Member]
|
Dec. 31, 2013
Other Voting Rights [Member]
Class B Common Stock (Shares)
|
Dec. 31, 2013
CME Group Omnibus Stock Plan [Member]
|
Dec. 31, 2013
CBOT Holdings Long-Term Equity Plan [Member]
|
Dec. 31, 2013
NYMEX Holdings Omnibus Long-Term Incentive Plan [Member]
|
Dec. 31, 2013
Director Stock Plan; Class A Shares [Member]
|
Dec. 31, 2013
Employee Stock Purchase Plan; Class A Shares [Member]
|
May 31, 2011
Share Repurchases; Class A Common Stock [Member]
|
|
Common Stock, Par or Stated Value Per Share | $ 0.01 | $ 0.01 | $ 0.01 | $ 0.01 | ||||||||||||||||
Common stock, voting rights | 6 | 2 | 1 | 1/6 | 1 | |||||||||||||||
Number of directors | 29 | 3 | 2 | 1 | 6 | |||||||||||||||
Shares granted, outstanding and exercised | 22,800,000 | |||||||||||||||||||
Number of shares reserved for awards under the plan | 40,200,000 | 2,300,000 | 5,000,000 | 625,000 | 500,000 | |||||||||||||||
Shares authorized for future awards, frozen awards | 1,600,000 | 3,500,000 | ||||||||||||||||||
Class A shares awarded under Director Stock Plan | 261,000 | |||||||||||||||||||
Market value of the shares an Employee Stock Purchase Plan | 90.00% | |||||||||||||||||||
Class A shares Purchased under Employee Stock Purchase Plan | 177,000 | |||||||||||||||||||
Share Buyback Program | $ 750.0 | |||||||||||||||||||
Number of Shares Company Repurchased | 4,000,000 | |||||||||||||||||||
Average Purchase Price Per Share | $ 54 | |||||||||||||||||||
Total Cost of Repurchased Shares | $ 220.4 |