Income Taxes (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Change in unrecognized tax benefits
Beginning balance	$ 52.5	$ 36.8	$ 40.1
Additions for tax positions related to the current year	4.1	3.8	3.3
Additions for tax positions of prior years	0	16.4	9.3
Reductions for tax positions of prior years	(1.1)	(0.1)	(5.6)
Settlements	(3.4)	(3.5)	(9.5)
Expiration of statute of limitations	(3.4)	(0.9)	(0.8)
Ending balance	$ 48.7	$ 52.5	$ 36.8