Segment and Geographic Area Information - Schedule of Segment Reporting Information to Consolidated Assets (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule Of Assets By Segment [Line Items]
Total segment assets	$ 31,912	$ 32,039
Elimination of intersegment receivables	(444)	(483)
Cash and cash equivalents	1,861	1,939	1,543	1,481
Corporate goodwill	5,170	5,157	5,028
Corporate fixed assets, net	18,947	19,282
Consolidated assets	40,179	40,120
Unallocated Amounts (Net of Tax) [Member]
Schedule Of Assets By Segment [Line Items]
Cash and cash equivalents	1,861	1,939
Deferred income taxes	4,061	3,738
Corporate goodwill	1,272	1,281
Corporate fixed assets, net	961	935
LIFO reserve	(770)	(801)
Other	$ 1,326	$ 1,472