Consolidated Statements of Comprehensive Income (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Tax effect on unrealized cash flow hedge gains/(losses)	$ (4.3)	$ 4.3	$ 10.1
Tax effects on reclassification adjustments on cash flow hedges	(8.9)	(16.7)	(4.3)
Tax effect on unrealized gain/(loss) on securities	0	0	0.3
Tax effects on reclassification adjustments on securities			(1.2)
Tax effects on prior service cost and unrecognized actuarial assumptions	$ (8.5)	$ 23.0	$ 4.4