Provision for Income Taxes (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current:
Federal	$ 2,342	$ 1,724	$ 1,657
State	171	274	458
Foreign	358	248	167
Total	2,871	2,246	2,282
Deferred:
Federal	(328)	452	(25)
State	(19)	(109)	47
Foreign	74	0	(13)
Total	(273)	343	9
Provision for income taxes	$ 2,598	$ 2,589	$ 2,291