Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 9.7	$ 80.3	$ 51.1	$ 233.4
Currency translation adjustments	38.7	(33.1)	22.7	(37.3)
Net unrealized pension and other benefit actuarial gains (losses) and prior service credits (net of tax)	(1.0)	0.3	(0.2)
Net unrealized gains (losses) on financial instruments (net of tax)	15.1	(10.2)	11.0	(15.8)
Total other comprehensive income (loss)	52.8	(43.0)	33.5	(53.1)
Comprehensive income	$ 62.5	$ 37.3	$ 84.6	$ 180.3