Cost-Reduction Actions - Liabilities and Expected Future Payments Related to Work-Force Reduction Actions (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2020
Restructuring Reserve [Roll Forward]
Additional provisions	$ 7.9	$ 2.6	$ 35.4	$ 5.2
Work-force Reductions
Restructuring Reserve [Roll Forward]
Balance at beginning of period			49.8
Additional provisions			11.3
Payments			(14.3)
Changes in estimates			(5.8)
Translation adjustments			(0.7)
Balance at end of period	40.3		40.3
2020 remaining six months	32.3		32.3
Beyond 2020	32.3		32.3
Work-force Reductions | Forecast
Restructuring Reserve [Roll Forward]
2020 remaining six months					$ 8.0
Beyond 2020					8.0
Work-force Reductions | U.S.
Restructuring Reserve [Roll Forward]
Balance at beginning of period			5.2
Additional provisions			3.0
Payments			(1.4)
Changes in estimates			0.1
Translation adjustments			0.0
Balance at end of period	6.9		6.9
2020 remaining six months	6.4		6.4
Beyond 2020	6.4		6.4
Work-force Reductions | U.S. | Forecast
Restructuring Reserve [Roll Forward]
2020 remaining six months					0.5
Beyond 2020					0.5
Work-force Reductions | International
Restructuring Reserve [Roll Forward]
Balance at beginning of period			44.6
Additional provisions			8.3
Payments			(12.9)
Changes in estimates			(5.9)
Translation adjustments			(0.7)
Balance at end of period	33.4		33.4
2020 remaining six months	25.9		25.9
Beyond 2020	$ 25.9		$ 25.9
Work-force Reductions | International | Forecast
Restructuring Reserve [Roll Forward]
2020 remaining six months					7.5
Beyond 2020					$ 7.5