Restructuring Costs - Schedule of Accrued Restructuring Costs Activity (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Restructuring Cost and Reserve [Line Items]
Beginning balance			$ 67.8
Restructuring costs, net	$ 2.9	$ 12.4	21.3	$ 64.1	$ 83.1
Payments			(47.9)
Reclassification			(12.7)
Foreign Currency and Other			(1.4)
Ending balance	27.1		27.1		67.8
Employee severance, termination benefits and relocation costs
Restructuring Cost and Reserve [Line Items]
Beginning balance			21.2
Restructuring costs, net			14.2
Payments			(24.7)
Reclassification			0.0
Foreign Currency and Other			(0.5)
Ending balance	10.2		10.2		21.2
Exited contractual commitments and other
Restructuring Cost and Reserve [Line Items]
Beginning balance			46.6
Restructuring costs, net			7.1
Payments			(23.2)
Reclassification			(12.7)
Foreign Currency and Other			(0.9)
Ending balance	$ 16.9		$ 16.9		$ 46.6