Restructuring - Costs Included in Selling, General & Administrative expenses on Consolidated Statements of Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 14.0	$ 40.6	$ 28.2
Severance and related costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	11.7	13.2	27.3
Other
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 2.3	$ 27.4	$ 0.9