Gains Losses Recognized in Accumulated Other Comprehensive Income AOCI Net of Tax Related to Derivative Instruments (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	$ 13	$ (49)
Cash Flow Hedging | Foreign Exchange Contract
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	14	(47)
Cash Flow Hedging | Commodity | Fuel oil contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	0	2
Cash Flow Hedging | Commodity | Natural gas contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in AOCI on Derivatives (Effective Portion)	$ (1)	$ (4)