Income Taxes (Summary of Income Tax Contingencies) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized income tax benefits at January 1	$ 2.9	$ 5.2	$ 6.1
Unrecognized Tax Benefits, Increases Resulting from Prior Period Tax Positions	20.5	0
Unrecognized Tax Benefits, Decreases Resulting from Prior Period Tax Positions			(0.8)
Decreases for settlements with taxing authorities	0	(2.3)	0
Decreases for lapses in the applicable statute of limitations	(0.8)	0	(0.1)
Unrecognized income tax benefits at December 31	$ 22.6	$ 2.9	$ 5.2