Stock-Based Compensation (Details) (USD $) In Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Stock-Based Compensation
Stock option expense	$ 6.0	$ 5.8	$ 17.6	$ 16.0
Restricted stock and unit awards expense	17.3	15.7	46.3	28.2
Total stock-based compensation expense	$ 23.3	$ 21.5	$ 63.9	$ 44.2
Stock-Based Compensation (Textuals) [Abstract]
Common shares issued from exercise of stock option outstanding			3.6		1.8