Consolidated Statements Of Income (USD $) In Millions, except Share data in Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenues
Clearing and transaction fees	$ 562.2	$ 732.7	$ 1,826.9	$ 2,111.8
Market data and information services	82.8	107.0	307.8	321.9
Access and communication fees	23.2	12.0	65.5	34.8
Other	15.0	22.5	53.5	75.6
Total Revenues	683.2	874.2	2,253.7	2,544.1
Expenses
Compensation and benefits	117.5	119.9	383.7	359.7
Communications	9.8	11.0	30.8	31.7
Technology support services	11.8	13.3	36.7	38.7
Professional fees and outside services	26.7	29.0	99.2	90.4
Amortization of purchased intangibles	26.2	33.0	90.3	99.2
Depreciation and amortization	34.5	32.4	103.0	95.1
Occupancy and building operations	18.8	18.5	57.8	56.9
Licensing and other fee agreements	19.2	22.6	63.2	64.7
Other	22.7	22.4	72.6	77.0
Total Expenses	287.2	302.1	937.3	913.4
Operating Income	396.0	572.1	1,316.4	1,630.7
Non-Operating Income (Expense)
Investment income	13.1	3.7	31.3	27.1
Gains (losses) on derivative investments	0	0	0	(0.1)
Interest and other borrowing costs	(30.2)	(29.0)	(88.2)	(87.8)
Equity in net losses of unconsolidated subsidiaries	16.5	(0.9)	14.8	(3.1)
Other nonoperating income (expense)	0.4	0	65.6	0
Total Non-Operating	(0.2)	(26.2)	23.5	(63.9)
Income before Income Taxes	395.8	545.9	1,339.9	1,566.8
Income tax provision	176.9	230.9	601.3	499.1
Net Income	218.9	315.0	738.6	1,067.7
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	0.9	(1.1)	9.1	1.3
Net Income Attributable to CME Group	$ 218.0	$ 316.1	$ 729.5	$ 1,066.4
Earnings per Common Share Attributable to CME Group:
Basic (in dollars per share)	$ 0.66	$ 0.95	$ 2.20	$ 3.20
Diluted (in dollars per share)	$ 0.66	$ 0.95	$ 2.20	$ 3.19
Weighted Average Number of Common Shares:
Basic (in shares)	331,377	332,289	331,091	333,449
Diluted (in shares)	332,458	333,337	332,147	334,507