Consolidated Statements of Comprehensive Income - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	[1]	$ 303.0	$ 561.6	$ 457.5
Other comprehensive (loss) income before tax:
Change in cumulative translation adjustment	[1]	272.1	(156.3)	(191.5)
Net change in cash flow hedges		(8.9)	7.9	0.2
Net change in unrealized components of defined benefit plans		31.9	(24.6)	49.3
Other comprehensive (loss) income, before tax		295.1	(173.0)	(142.0)
Benefit (cost) for taxes related to defined benefit plans		(7.8)	7.6	(14.3)
Other comprehensive (loss) income, net of tax		287.3	(165.4)	(156.3)
Comprehensive income	[1]	590.3	396.2	301.2
Less: Comprehensive (loss) income attributable to non-controlling interest		(114.8)	(13.9)	0.1
Comprehensive income attributable to controlling interest		$ 705.1	$ 410.1	$ 301.1

[1] See Note 13 for further details – includes tax effects where applicable.