Derivative Instruments and Hedging Activities - Fair Value of Derivative Instruments on Gross Basis (Detail) - Designated as Hedging Instrument [Member] - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 43.2	$ 112.1
Derivative Liabilities	32.5	13.1
Foreign Exchange Forward Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	18.1	41.8
Foreign Exchange Forward Contracts [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	5.5	9.8
Foreign Exchange Forward Contracts [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	8.3	7.9
Foreign Exchange Forward Contracts [Member] | Other Long-term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	9.1	5.2
Cross-currency Interest Rate Swaps [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	2.9
Cross-currency Interest Rate Swaps [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	16.7	$ 60.5
Cross-currency Interest Rate Swaps [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	13.3
Cross-currency Interest Rate Swaps [Member] | Other Long-term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	$ 1.8