Changes in Accumulated Other Comprehensive Losses (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period				$ (6,369)	[1]
Components of Other Comprehensive Income (Loss):
Before Reclassifications				(49)	[1]
Reclassifications				421	[1],[2]
Other Comprehensive Gain, Net of Tax	81		174	372	[1]	464
Balance at end of period	(5,997)	[1]		(5,997)	[1]
Income tax expense	3,839		4,624	11,068		15,317
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period				(65)	[1]
Components of Other Comprehensive Income (Loss):
Before Reclassifications				45	[1]
Reclassifications				0	[1],[2]
Other Comprehensive Gain, Net of Tax				45	[1]
Balance at end of period	(20)	[1]		(20)	[1]
Unrealized Holding Gains (Losses) on Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period				1	[1]
Components of Other Comprehensive Income (Loss):
Before Reclassifications				(6)	[1]
Reclassifications				0	[1],[2]
Other Comprehensive Gain, Net of Tax				(6)	[1]
Balance at end of period	(5)	[1]		(5)	[1]
Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period				125	[1]
Components of Other Comprehensive Income (Loss):
Before Reclassifications				(69)	[1]
Reclassifications				(1)	[1],[2]
Other Comprehensive Gain, Net of Tax				(70)	[1]
Balance at end of period	55	[1]		55	[1]
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period				(6,430)	[1]
Components of Other Comprehensive Income (Loss):
Before Reclassifications				(19)	[1]
Reclassifications				422	[1],[2]
Other Comprehensive Gain, Net of Tax				403	[1]
Balance at end of period	(6,027)	[1]		(6,027)	[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				665
Income tax expense				$ 243

[1] All amounts are net of tax.

[2] Refer to Note 9, Employee Benefits for reclassified components totaling $665 million that are included in employee benefit costs for the nine months ending September 30, 2013. Related income taxes for the same period, totaling $243 million, are reflected in Income Tax Expense on the Consolidated Statement of Income. All other reclassified amounts were insignificant.