Income Taxes (Unrecognized Tax Benefits) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes [Abstract]
Balance at beginning of year	$ 27.3	$ 25.9	$ 26.5
Increases related to prior period tax positions	96.9	1.8
Decreases related to prior period tax positions	(2.9)	(0.4)	(0.4)
Increases related to current period tax positions	19.3	1.8	1.7
Settlements	(0.3)	(0.6)	(1.1)
Lapse in applicable statute of limitations	(0.5)	(1.2)	(0.8)
Balance at end of year	$ 139.8	$ 27.3	$ 25.9