Income Taxes (Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 61.7	$ 55.9	$ 59.5
State	14.1	14.2	17.8
Foreign	4.8	9.3	4.6
Total current	80.6	79.4	81.9
Deferred:
Federal	(0.7)	15.0	23.2
State	1.1	3.9	1.0
Foreign	7.1	0.8	1.5
Total deferred	7.5	19.7	25.7
Total provision for income taxes	$ 88.1	$ 99.1	$ 107.6