Reconciliation of Total Reportable Segments Operating Income to Consolidated Income before Provision for Income Taxes (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Pension remeasurement (Note 6)	$ 237		$ 237
Operating income	6,555	5,651	12,777	10,846
Equity in earnings of unconsolidated businesses	120	72	115	175
Other income, net	25	34	64	53
Interest expense	(514)	(679)	(1,051)	(1,364)
Income Before Provision For Income Taxes	6,186	5,078	11,905	9,710
Corporate, Eliminations and Other
Segment Reporting Information [Line Items]
Operating income	(220)	(250)	(429)	(429)
Total Segments
Segment Reporting Information [Line Items]
Operating income	$ 6,538	$ 5,901	$ 12,969	$ 11,275