Other income (expense), net (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Income and Expenses [Abstract]
Foreign currency transactions	$ 0.3	$ (0.9)	$ (6.1)	$ (3.7)
Foreign currency denominated loans revaluation	0.2	16.8	0.0	17.3
Undesignated foreign currency derivative instruments	0.5	(20.6)	0.6	(26.2)
Undesignated swap contracts	(0.1)	(1.0)	(6.1)	(3.8)
Non-operating retirement benefits	2.2	0.5	6.5	1.7
Debt refinancing costs	0.0	0.0	(0.1)	0.0
Other	(0.7)	(0.3)	(2.2)	(2.5)
Total other income (expense), net	$ 2.4	$ (5.5)	$ (7.4)	$ (17.2)