Schedule of Changes in Balance Sheet Position of Restructuring Reserves (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Reserve at beginning of the period	$ 41.7	$ 37.5
Provision/charge	3.3	2.5
Provision/reversal		(0.5)
Cash payments	(4.9)	(9.3)
Translation difference	1.0	0.6
Reserve at end of the period	41.1	30.8
Restructuring employee-related
Restructuring Cost and Reserve [Line Items]
Reserve at beginning of the period	41.4	37.1
Provision/charge	3.3	2.3
Provision/reversal		(0.1)
Cash payments	(4.9)	(9.3)
Translation difference	1.0	0.6
Reserve at end of the period	40.8	30.6
Restructuring Other
Restructuring Cost and Reserve [Line Items]
Reserve at beginning of the period	0.3	0.4
Provision/charge		0.2
Provision/reversal		(0.4)
Reserve at end of the period	$ 0.3	$ 0.2