Segment and Geographical Area Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information, Operating Income (Loss) [Abstract]
External revenue	$ 229.9	$ 196.1	$ 668.6	$ 586.4
U.S. [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
External revenue	171.8	143.5	503.4	430.6
Non-U.S. [Member]
Segment Reporting Information, Operating Income (Loss) [Abstract]
External revenue	$ 58.1	$ 52.6	$ 165.2	$ 155.8