Income Taxes (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current:
Federal	$ 84.3	$ 71.9	$ 47.5
State	10.1	8.5	7.3
Foreign	9.6	16.2	13.4
Total current	104.0	96.6	68.2
Deferred:
Federal	2.3	(4.0)	0.7
State	1.0	2.5	(0.2)
Foreign	2.2	(0.7)	(2.0)
Total deferred	5.5	(2.2)	(1.5)
Total income tax provision	$ 109.5	$ 94.4	$ 66.7