Schedule of Changes in Balance Sheet Position of Restructuring Reserves (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, beginning balance	$ 24.7	$ 66.6	$ 37.5	$ 87.9
Provision/ Charge	21.3	3.4	25.1	20.6
Provision/ Reversal	(0.4)	(0.1)	(4.6)	(0.8)
Cash payments	(4.1)	(11.8)	(18.8)	(50.9)
Translation difference	2.3	0.3	4.6	1.6
Restructuring reserve, ending balance	43.8	58.4	43.8	58.4
Restructuring employee-related
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, beginning balance	24.5	66.5	37.1	87.7
Provision/ Charge	21.3	3.4	24.9	20.6
Provision/ Reversal	(0.4)	(0.1)	(4.2)	(0.8)
Cash payments	(4.1)	(11.8)	(18.8)	(50.9)
Translation difference	2.3	0.4	4.6	1.8
Restructuring reserve, ending balance	43.6	58.4	43.6	58.4
Other Restructuring
Restructuring Cost and Reserve [Line Items]
Restructuring reserve, beginning balance	0.2	0.1	0.4	0.2
Provision/ Charge			0.2
Provision/ Reversal			(0.4)
Translation difference	0.0	(0.1)	0.0	(0.2)
Restructuring reserve, ending balance	$ 0.2	$ 0.0	$ 0.2	$ 0.0