Income Taxes - Provision/(Benefit) For Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current
U.S. federal	$ 0.7	$ 0.8	$ (5.9)
Foreign	36.1	49.0	72.9
State and local	1.5	1.9	1.7
Total current	38.3	51.7	68.7
Deferred
U.S. federal	78.1	4.6	7.6
Foreign	(11.7)	(19.8)	(44.9)
State and local	12.0	0.7	(3.1)
Total deferred	78.4	(14.5)	(40.4)
Income tax expense (benefit)	$ 116.7	$ 37.2	$ 28.3