Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Income Tax Contingency [Line Items]
Effective income tax rate	28.50%	24.40%	29.90%	30.90%
Overall increase/decrease in unrecognized tax benefits (UTBS)			$ (0.1)	$ 21.8
Prepaid taxes	12.6		12.6		82.3
Gross [Member]
Income Tax Contingency [Line Items]
Overall increase/decrease in unrecognized tax benefits (UTBS)	12.6		6.2
Net [Member]
Income Tax Contingency [Line Items]
Overall increase/decrease in unrecognized tax benefits (UTBS)	$ 10.4		$ 8.7