Derivative Instruments and Hedging Activities - Fair Value of Derivative Instruments on Gross Basis (Detail) - Designated as Hedging Instrument [Member] - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Derivative Assets	$ 60.1	$ 23.8
Derivative Liabilities	25.1	68.6
Foreign Exchange Forward Contracts [Member] | Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	15.0	14.5
Foreign Exchange Forward Contracts [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	7.9	4.8
Foreign Exchange Forward Contracts [Member] | Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	18.2	45.8
Foreign Exchange Forward Contracts [Member] | Other Long-term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	5.7	22.8
Interest Rate Swaps [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	4.6	$ 4.5
Cross-currency Interest Rate Swaps [Member] | Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Assets	32.6
Cross-currency Interest Rate Swaps [Member] | Other Long-term Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liabilities	$ 1.2