CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 118.0	$ 88.2	$ 274.5	$ 358.6
Other comprehensive income before tax:
Change in cumulative translation adjustments	(30.0)	57.9	(134.8)	231.9
Net change in cash flow hedges		(3.9)	1.1	(10.5)
Net change in unrealized components of defined benefit plans	0.5	1.9	8.0	5.4
Other comprehensive (loss) income, before tax	(29.5)	55.9	(125.7)	226.8
Tax effect allocated to other comprehensive income	(0.1)	(0.6)	(1.9)	(1.6)
Other comprehensive (loss) income, net of tax	(29.6)	55.3	(127.6)	225.2
Comprehensive income (loss)	88.4	143.5	146.9	583.8
Less: Comprehensive income (loss) attributable to non-controlling interest	(0.5)	(1.8)	(7.6)	1.6
Comprehensive income attributable to controlling interest	$ 88.9	$ 145.3	$ 154.5	$ 582.2