Schedule of Changes in Balance Sheet Position of Restructuring Reserves Related to Continuing Operations (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Reserve at beginning of the period	$ 36.0	$ 24.7	$ 39.6	$ 35.8
Provision/charge	0.5	21.3	4.8	24.6
Provision/reversal		(0.4)		(4.2)
Cash payments	(4.0)	(4.1)	(10.8)	(17.0)
Translation difference	0.0	2.2	(1.1)	4.5
Reserve at end of the period	32.5	43.7	32.5	43.7
Restructuring employee-related
Restructuring Cost and Reserve [Line Items]
Reserve at beginning of the period	35.8	24.4	39.4	35.7
Provision/charge	0.5	21.3	4.8	24.4
Provision/reversal		(0.4)		(4.2)
Cash payments	(4.0)	(4.1)	(10.8)	(17.0)
Translation difference	0.0	2.3	(1.1)	4.6
Reserve at end of the period	32.3	43.5	32.3	43.5
Restructuring Other
Restructuring Cost and Reserve [Line Items]
Reserve at beginning of the period	0.2	0.3	0.2	0.1
Provision/charge				0.2
Translation difference		(0.1)		(0.1)
Reserve at end of the period	$ 0.2	$ 0.2	$ 0.2	$ 0.2