Consolidated Statements Comprehensive Income (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Statement of Other Comprehensive Income [Abstract]
Tax benefit (expense), pension liability	$ (0.6)	$ 6.7	$ 2.9
Tax benefit (expense), unrealized gain (loss) on hedging activities	$ (8.1)	$ 13.0	$ (20.0)