Intangible Assets and Goodwill (Goodwill Activity) (Details) - USD ($) $ in Millions |
12 Months Ended | |
---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
|
Total Goodwill, beginning balance | $ 7,569.0 | $ 7,569.0 |
Business Combinations | 0.0 | 0.0 |
Goodwill, Written off Related to Sale of Business Unit | 0.0 | 0.0 |
Other Activity | 0.0 | 0.0 |
Total Goodwill, ending balance | 7,569.0 | 7,569.0 |
CBOT holdings [Member] | ||
Total Goodwill, beginning balance | 5,066.4 | 5,035.7 |
Business Combinations | 0.0 | 0.0 |
Goodwill, Transfers | 0.0 | 30.7 |
Other Activity | 0.0 | 0.0 |
Total Goodwill, ending balance | 5,066.4 | 5,066.4 |
NYMEX holdings [Member] | ||
Total Goodwill, beginning balance | 2,462.2 | 2,462.2 |
Business Combinations | 0.0 | 0.0 |
Goodwill, Written off Related to Sale of Business Unit | 0.0 | 0.0 |
Other Activity | 0.0 | 0.0 |
Total Goodwill, ending balance | 2,462.2 | 2,462.2 |
Other Affiliates [Member] | ||
Total Goodwill, beginning balance | 40.4 | 71.1 |
Business Combinations | 0.0 | 0.0 |
Goodwill, Transfers | 0.0 | (30.7) |
Other Activity | 0.0 | 0.0 |
Total Goodwill, ending balance | $ 40.4 | $ 40.4 |