Restructuring - Restructuring Related Costs Included in Selling, General & Administrative expenses on Consolidated Statements of Income (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 12.8	$ 12.1	$ 33.7	$ 12.6
Severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	12.8	11.3	33.4	11.9
Other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 0.0	$ 0.8	$ 0.3	$ 0.7