Employee Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
U.S. [Member]
Change in Benefit Obligation
Benefit obligation at January 1	$ 12,165	$ 10,271
Service cost	452	374	337
Interest cost	435	463	486
Plan participants contributions	0	0
Plan amendments	94	0
Actuarial loss (gain)	1,322	1,920
Foreign currency exchange rate changes	0	0
Benefits paid	(763)	(863)
Divestitures	(51)	0
Curtailments	0	0
Benefit obligation at December 31	13,654	12,165	10,271
Change in Plan Assets
Fair value of plan assets at January	8,720	8,579
Actual return on plan assets	1,149	(143)
Foreign currency exchange rate changes	0	0
Contributions to employee pension plans	844	1,147
Plan participants contributions	0	0
Benefits paid	(763)	(863)
Divestitures	(41)	0
Fair value of plan assets at December 31	9,909	8,720	8,579
Funded Status at December 31	(3,745)	(3,445)
International [Member]
Change in Benefit Obligation
Benefit obligation at January 1	5,519	5,070
Service cost	181	174	153
Interest cost	320	325	307
Plan participants contributions	7	6
Plan amendments	37	27
Actuarial loss (gain)	417	318
Foreign currency exchange rate changes	114	(98)
Benefits paid	(308)	(303)
Divestitures	0	0
Curtailments	0	0
Benefit obligation at December 31	6,287	5,519	5,070
Change in Plan Assets
Fair value of plan assets at January	3,577	3,503
Actual return on plan assets	375	118
Foreign currency exchange rate changes	90	(66)
Contributions to employee pension plans	384	319
Plan participants contributions	7	6
Benefits paid	(308)	(303)
Divestitures	0	0
Fair value of plan assets at December 31	4,125	3,577	3,503
Funded Status at December 31	(2,162)	(1,942)
Other Benefits [Member]
Change in Benefit Obligation
Benefit obligation at January 1	3,765	3,605
Service cost	61	58	39
Interest cost	153	180	175
Plan participants contributions	151	148
Plan amendments	11	0
Actuarial loss (gain)	44	149
Foreign currency exchange rate changes	1	(19)
Benefits paid	(350)	(346)
Divestitures	(49)	0
Curtailments	0	(10)
Benefit obligation at December 31	3,787	3,765	3,605
Change in Plan Assets
Fair value of plan assets at January	0	0
Actual return on plan assets	0	0
Foreign currency exchange rate changes	0	0
Contributions to employee pension plans	199	198
Plan participants contributions	151	148
Benefits paid	(350)	(346)
Divestitures	0	0
Fair value of plan assets at December 31	0	0	0
Funded Status at December 31	$ (3,787)	$ (3,765)

The difference between fair value of plan assets at the end of the period and the fair value at the beginning of the period, adjusted for contributions and payments of benefits during the period, and after adjusting for taxes and other expenses, as applicable.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Actual Return on Plan Assets (Component of Net Periodic Pension Cost)

-URI http://asc.fasb.org/extlink&oid=6504226

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 87

-Paragraph 264

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph d(iv)(b)(i)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 106

-Paragraph 518

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Actual Return on Plan Assets (Component of Net Periodic Postretirement Benefit Cost)

-URI http://asc.fasb.org/extlink&oid=6504192

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.