Income Taxes - Income Tax Expense by Component (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ 224.7	$ 192.6	$ 258.9
State	56.1	43.3	29.8
Foreign	20.0	17.7	21.3
Total current	300.8	253.6	310.0
Deferred:
Domestic	(83.0)	(52.7)	(167.6)
Foreign	(4.9)	(3.4)	(4.8)
Total deferred	(87.9)	(56.1)	(172.4)
Income tax expense	$ 212.9	$ 197.5	$ 137.6