Income Taxes (Provision for Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current:
Federal	$ 131.8	$ 104.0	$ 72.0
State	26.6	21.6	17.0
Foreign	14.5	7.8	13.4
Total current	172.9	133.4	102.4
Deferred:
Federal	(22.2)	(13.9)	(2.6)
State	(4.9)	(3.1)	(1.5)
Foreign	1.6	2.3	(2.2)
Total deferred	(25.5)	(14.7)	(6.3)
Total provision for income taxes	$ 147.4	$ 118.7	$ 96.1