Changes in Accumulated Other Comprehensive Losses (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at January 1	$ (6,369)	[1]
Components of Other Comprehensive Income (Loss):
Before Reclassifications	(37)	[1]
Reclassifications	137	[1],[2]
Other Comprehensive Gain, Net of Tax	100	[1]	147
Balance at March 31	(6,269)	[1]
Income tax expense	4,044		5,570
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at January 1	(65)	[1]
Components of Other Comprehensive Income (Loss):
Before Reclassifications	(11)	[1]
Reclassifications	0	[1],[2]
Other Comprehensive Gain, Net of Tax	(11)	[1]
Balance at March 31	(76)	[1]
Unrealized Holding Gains (Losses) on Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at January 1	1	[1]
Components of Other Comprehensive Income (Loss):
Before Reclassifications	(1)	[1]
Reclassifications	0	[1],[2]
Other Comprehensive Gain, Net of Tax	(1)	[1]
Balance at March 31	0	[1]
Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at January 1	125	[1]
Components of Other Comprehensive Income (Loss):
Before Reclassifications	0	[1]
Reclassifications	(3)	[1],[2]
Other Comprehensive Gain, Net of Tax	(3)	[1]
Balance at March 31	122	[1]
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at January 1	(6,430)	[1]
Components of Other Comprehensive Income (Loss):
Before Reclassifications	(25)	[1]
Reclassifications	140	[1],[2]
Other Comprehensive Gain, Net of Tax	115	[1]
Balance at March 31	(6,315)	[1]
Defined Benefit Plans [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Components of Other Comprehensive Income (Loss):
Employee benefits reclassification component, included in employee benefit costs	220
Income tax expense	$ 80

[1] All amounts are net of tax.

[2] Refer to Note 9, Employee Benefits for reclassified components totaling $220 million that are included in employee benefit costs for the three months ending March 31, 2013. Related income taxes for the same period, totaling $80 million, are reflected in Income Tax Expense on the Consolidated Statement of Income. All other reclassified amounts were insignificant.