Cost-Reduction Actions - Individual Components of Work Force Reduction and Idle Lease Cost (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019
Restructuring Reserve [Roll Forward]
Changes in estimates	$ (0.9)		$ (3.1)
Work-force Reductions
Restructuring Reserve [Roll Forward]
Balance at beginning of period		$ 86.2
Payments		(40.9)
Changes in estimates		0.2
Translation adjustments		(2.5)
Balance at end of period		43.0
2019 remaining three months		29.2
Beyond 2019		29.2
Work-force Reductions | Forecast
Restructuring Reserve [Roll Forward]
2019 remaining three months				$ 13.8
Beyond 2019				13.8
Work-force Reductions | U.S.
Restructuring Reserve [Roll Forward]
Balance at beginning of period		6.1
Payments		(3.0)
Changes in estimates		(1.1)
Translation adjustments		0.0
Balance at end of period		2.0
2019 remaining three months		1.5
Beyond 2019		1.5
Work-force Reductions | U.S. | Forecast
Restructuring Reserve [Roll Forward]
2019 remaining three months				0.5
Beyond 2019				0.5
Work-force Reductions | International
Restructuring Reserve [Roll Forward]
Balance at beginning of period		80.1
Payments		(37.9)
Changes in estimates		1.3
Translation adjustments		(2.5)
Balance at end of period		41.0
2019 remaining three months		27.7
Beyond 2019		$ 27.7
Work-force Reductions | International | Forecast
Restructuring Reserve [Roll Forward]
2019 remaining three months				13.3
Beyond 2019				$ 13.3