Income Taxes - Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
U.S.:
Federal	$ (0.8)	$ (4.1)	$ 14.9
State and local	1.3	0.0	0.4
Foreign	56.8	68.5	63.2
Total current	57.3	64.4	78.5
U.S.:
Federal	(40.4)	33.2	(35.1)
State and local	1.1	(0.8)	(4.3)
Foreign	(13.7)	(35.5)	(15.3)
Total deferred	(53.0)	(3.1)	(54.7)
Income tax expense	$ 4.3	$ 61.3	$ 23.8