Components of Income Before Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Domestic	$ 921.6	$ 726.7	$ 671.8
Foreign	52.2	47.0	47.7
Income before Income Taxes	$ 973.8	$ 773.7	$ 719.5