Income Taxes - Income Tax (Benefit) Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
U.S.:
Federal	$ (4.1)	$ 14.9	$ (1.2)
State and local	0.0	0.4	1.0
Foreign	68.5	63.2	65.7
Total current	64.4	78.5	65.5
U.S.:
Federal	33.2	(35.1)	(78.4)
State and local	(0.8)	(4.3)	(2.1)
Foreign	(35.5)	(15.3)	(53.6)
Total deferred	(3.1)	(54.7)	(134.1)
Income tax expense (benefit)	$ 61.3	$ 23.8	$ (68.6)