Income Taxes - Components of Provision for Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current:
Federal	$ 86.8	$ 37.7	$ 58.1
State and other	25.0	13.7	17.8
Total current expense	111.8	51.4	75.9
Deferred:
Federal	23.6	39.5	32.0
State and other	4.2	12.9	8.0
Total deferred expense	27.8	52.4	40.0
Total income tax expense related to continuing operations	$ 139.6	$ 103.8	$ 115.9