Organization and Business (Details) (USD $)
In Millions, unless otherwise specified |
6 Months Ended | 12 Months Ended | ||||
---|---|---|---|---|---|---|
Jun. 30, 2013
|
Dec. 31, 2014
|
Dec. 31, 2012
|
Apr. 30, 2013
|
Mar. 18, 2010
|
Jun. 30, 2012
|
|
Business Acquisition [Line Items] | ||||||
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests | $ 80.0 | $ 5.8 | ||||
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage | 51.00% | |||||
S&P/Dow Jones Indices LLC [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Equity Method Investment, Ownership Percentage | 27.00% | |||||
Dow Jones [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners | 10.00% | |||||
CME Group net of non-controlling interest [Member] | ||||||
Business Acquisition [Line Items] | ||||||
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners | 24.40% | 24.40% |