Long-Term Debt (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule Of Debt Instruments [Line Items]
U.S. Dollar notes	$ 16,887	$ 21,766
Euro notes	1,119	3,690
Sterling notes	1,109	1,074
Other foreign currency obligations	32	178
Capital leases and other	4	41
Total	19,151	26,749
Less current portion of long-term debt	(3,577)	(3,654)
Long-term debt	$ 15,574	$ 23,095