Fair Value of Derivatives Not Designated and Designated as Hedges (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Derivatives Fair Value [Line Items]
Derivatives assets	$ 4.6	$ 15.3
Derivatives liabilities	17.0	24.0
Not Designated as Hedging Instrument | Prepaid Expenses and Other Current Assets
Derivatives Fair Value [Line Items]
Derivatives assets	0.8	0.6
Not Designated as Hedging Instrument | Accrued Liabilities
Derivatives Fair Value [Line Items]
Derivatives liabilities	10.3	24.0
Designated as Hedging Instrument | Prepaid Expenses and Other Current Assets
Derivatives Fair Value [Line Items]
Derivatives assets	3.8
Designated as Hedging Instrument | Other Noncurrent Assets
Derivatives Fair Value [Line Items]
Derivatives assets		14.7
Designated as Hedging Instrument | Other Noncurrent Liabilities
Derivatives Fair Value [Line Items]
Derivatives liabilities	$ 6.7