CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 43.6	$ 60.9
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	20.0	5.9
Defined benefit pension and other postretirement plan adjustments, net of tax of $(0.3) and $(0.1)	(0.7)	(0.1)
Net gain on investment securities, net of tax of $0.1	0.0	0.3
Net gain on derivatives, net of tax of $0.8 and $0.8	2.2	1.7
Other comprehensive income, net of tax	21.5	7.8
Comprehensive income	$ 65.1	$ 68.7