CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) income	$ (174.3)	$ 109.4	$ (99.4)	$ 220.9
Other comprehensive income (loss) before tax:
Change in cumulative translation adjustments	26.6	6.1	(75.2)	26.9
Net change in unrealized components of defined benefit plans	3.1	(0.0)	4.0	0.1
Other comprehensive income (loss), before tax	29.7	6.1	(71.2)	27.0
Tax effect allocated to other comprehensive loss	(0.9)	(0.0)	(1.2)	(0.0)
Other comprehensive income (loss), net of tax	28.8	6.1	(72.4)	27.0
Comprehensive (loss) income	(145.5)	115.5	(171.8)	247.9
Less: Comprehensive income attributable to non-controlling interest	0.4	0.1	0.3	0.5
Comprehensive (loss) income attributable to controlling interest	$ (145.9)	$ 115.4	$ (172.1)	$ 247.4