Income Taxes - Current and Deferred Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal U.S.	$ 48.3	$ 170.0	$ 197.2
Non-U.S.	96.3	69.8	59.5
State and local	7.8	10.5	29.7
Deferred:
Federal U.S.	27.3	(62.0)	(8.9)
Non-U.S.	(19.6)	(1.7)	(4.7)
State and local	0.0	2.7	(2.5)
Income tax provision	$ 160.1	$ 189.3	$ 270.3