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, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Other current assets [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amount	$ 46.6	$ 30.3
Offset	8.3	15.2
Net Amount in Balance Sheet	38.3	15.1
Other assets [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amount	21.8	19.8
Offset	6.3	6.5
Net Amount in Balance Sheet	15.5	13.3
Other current liabilities [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amount	16.2	20.2
Offset	8.3	15.2
Net Amount in Balance Sheet	7.9	5.0
Other long-term liabilities [Member]
Derivatives And Hedging Activities [Line Items]
Gross Amount	12.8	12.3
Offset	6.3	6.5
Net Amount in Balance Sheet	$ 6.5	$ 5.8