Comprehensive Income - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net increase to Other Comprehensive Income or Loss upon the translation	$ 84	$ 117	$ 28	$ 25
Changes in derivative financial instruments, net of tax	64	(71)	74	(29)
Changes in derivative financial instruments, tax	$ 23	$ 28	$ 27	$ 12

Amount after tax, before reclassification adjustments, resulting from the process of expressing in the reporting currency of the reporting entity those amounts that are denominated or measured in a different currency, and from transactions whose terms are denominated in a currency other than the entity's functional currency.

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+ Details