Derivative Instruments and Hedging Activities - Schedule of Effects of Master Netting Agreements on Condensed Consolidated Balance Sheets (Detail) - Cash Flow Hedges [Member] - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Other Current Assets [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gross Amount	$ 15.9	$ 57.9
Offset	13.6	20.6
Net Amount in Balance Sheet	2.3	37.3
Other Assets [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gross Amount	7.4	34.9
Offset	5.8	6.8
Net Amount in Balance Sheet	1.6	28.1
Other Current Liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gross Amount	37.2	20.9
Offset	13.6	20.6
Net Amount in Balance Sheet	23.6	0.3
Other Long-term Liabilities [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gross Amount	21.7	6.9
Offset	5.8	6.8
Net Amount in Balance Sheet	$ 15.9	$ 0.1