Pre-tax Impacts of Foreign Currency Cash Flow Derivatives on Comprehensive Income and Results of Operations (Detail) (Other income (expense) [Member], Foreign exchange contracts [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Other income (expense) [Member] | Foreign exchange contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Gain or (Loss) Recognized in OCI (Effective Portion)	$ (15)	$ 25	$ (14)	$ 11
Derivative Gain or (Loss) Reclassified from AOCI into Income (Effective Portion)	$ (14)	$ 33	$ (17)	$ 21