Derivatives and Financial Instruments - Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract liabilities	$ (11.6)		$ (69.6)
Cost-method Investments, Realized Losses	21.2	$ 12.0
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract assets	0.1
Foreign currency contract liabilities	(11.6)		(69.6)
Deferred compensation plan assets	21.3		22.6
Total recurring fair value measurements	9.8		(47.0)
Level 1 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract assets	0.0
Foreign currency contract liabilities	0.0		0.0
Deferred compensation plan assets	12.5		12.2
Total recurring fair value measurements	12.5		12.2
Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract assets	0.1
Foreign currency contract liabilities	(11.6)		(69.6)
Deferred compensation plan assets	0.0		0.0
Total recurring fair value measurements	(11.5)		(69.6)
Level 3 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract assets	0.0
Foreign currency contract liabilities	0.0		0.0
Deferred compensation plan assets	0.0		0.0
Total recurring fair value measurements	0.0		0.0
NAV | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contract assets	0.0
Foreign currency contract liabilities	0.0		0.0
Deferred compensation plan assets	8.8		10.4
Total recurring fair value measurements	$ 8.8		$ 10.4