Income Taxes (Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ 59.5	$ 86.1	$ 106.0
State	17.8	12.5	14.5
Foreign	4.6	15.0	9.7
Total current	81.9	113.6	130.2
Deferred:
Federal	23.2	43.8	(4.5)
State	1.0	0.9	(1.2)
Foreign	1.5	(1.4)	(0.4)
Total deferred	25.7	43.3	(6.1)
Total provision for income taxes	$ 107.6	$ 156.9	$ 124.1