Restructuring Costs - Schedule of Accrued Restructuring Costs Activity (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Beginning balance	$ 70.8	$ 84.5
Restructuring Costs, Net	27.1	86.8	$ 95.3
Payments	(59.7)	(76.5)
Restructuring reserve, reclassifications	(13.8)
Foreign Currency and Other	(1.9)	(24.0)
Ending balance	22.5	70.8	84.5
Non-cash restructuring charges	1.3	22.2
Employee severance and termination benefits
Restructuring Cost and Reserve [Line Items]
Beginning balance	23.8	52.4
Restructuring Costs, Net	20.2	50.1
Payments	(32.7)	(53.3)
Restructuring reserve, reclassifications	0.0
Foreign Currency and Other	(1.1)	(25.4)
Ending balance	10.2	23.8	52.4
Exited contractual commitments and other
Restructuring Cost and Reserve [Line Items]
Beginning balance	47.0	32.1
Restructuring Costs, Net	6.9	36.7
Payments	(27.0)	(23.2)
Restructuring reserve, reclassifications	(13.8)
Foreign Currency and Other	(0.8)	1.4
Ending balance	$ 12.3	$ 47.0	$ 32.1