Income Taxes - Provision (Benefit) for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
U.S. federal	$ 27.7	$ 6.3	$ 25.6
U.S. state and local	10.2	0.9	1.5
Non-U.S.	79.5	45.2	47.8
Deferred:
U.S. federal	(53.4)	(13.2)	14.4
U.S. state and local	(5.5)	0.5	(0.7)
Non-U.S.	(45.5)	(7.9)	(8.5)
Provision for income taxes	$ 13.0	$ 31.8	$ 80.1