Restructuring - Restructuring Related Costs Included in Selling, General & Administrative expenses on Consolidated Statements of Income (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 20.9	$ 0.5
Severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	20.6	0.6
Other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 0.3	$ (0.1)