Income Taxes (Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ 101.0	$ 84.3	$ 71.9
State	13.1	10.1	8.5
Foreign	3.6	9.6	16.2
Total current	117.7	104.0	96.6
Deferred:
Federal	(21.4)	2.3	(4.0)
State	(0.6)	1.0	2.5
Foreign	(0.3)	2.2	(0.7)
Total deferred	(22.3)	5.5	(2.2)
Total provision for income taxes	$ 95.4	$ 109.5	$ 94.4