Income Taxes - Provision/(Benefit) For Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current
U.S. federal	$ 0.8	$ (5.9)	$ (68.6)
Foreign	49.0	72.9	54.0
State and local	1.9	1.7	(10.6)
Total current	51.7	68.7	(25.2)
Deferred
U.S. federal	4.6	7.6	3.6
Foreign	(19.8)	(44.9)	(50.2)
State and local	0.7	(3.1)	2.8
Total deferred	(14.5)	(40.4)	(43.8)
Income tax expense (benefit)	$ 37.2	$ 28.3	$ (69.0)