Employee Benefit Plans (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net Periodic Benefit Cost
Curtailment losses (gains)			$ 0
Changes Recognized in Other Comprehensive Income
Prior service cost during period	142	27	12
Amortization to net income of net prior service credits	61	26	61
U.S. [Member]
Net Periodic Benefit Cost
Service cost	452	374	337
Interest cost	435	463	486
Expected return on plan assets	(634)	(613)	(538)
Amortization of prior service (credits) costs	(7)	(8)	(8)
Recognized actuarial losses	470	310	318
Settlement losses	220	298	186
Curtailment losses (gains)	0	0	0
Total net periodic benefit cost	936	824	781
Changes Recognized in Other Comprehensive Income
Net actuarial loss during period	805	2,671	242
Amortization of actuarial loss	(700)	(608)	(504)
Prior service cost during period	94	0	0
Amortization to net income of net prior service credits	7	8	8
Total changes recognized in other comprehensive income	206	2,071	(254)
Recognized in Net Periodic Benefit Cost and Other Comprehensive Income	1,142	2,895	527
International [Member]
Net Periodic Benefit Cost
Service cost	181	174	153
Interest cost	320	325	307
Expected return on plan assets	(269)	(283)	(241)
Amortization of prior service (credits) costs	18	19	22
Recognized actuarial losses	136	101	98
Settlement losses	5	0	6
Curtailment losses (gains)	0	35
Total net periodic benefit cost	391	371	345
Changes Recognized in Other Comprehensive Income
Net actuarial loss during period	330	448	118
Amortization of actuarial loss	(141)	(101)	(104)
Prior service cost during period	37	27	0
Amortization to net income of net prior service credits	(18)	(54)	(22)
Total changes recognized in other comprehensive income	208	320	(8)
Recognized in Net Periodic Benefit Cost and Other Comprehensive Income	599	691	337
Other Benefits [Member]
Net Periodic Benefit Cost
Service cost	61	58	39
Interest cost	153	180	175
Expected return on plan assets	0	0	0
Amortization of prior service (credits) costs	(72)	(72)	(75)
Recognized actuarial losses	56	64	27
Settlement losses	(26)	0	0
Curtailment losses (gains)	0	(10)	0
Total net periodic benefit cost	172	220	166
Changes Recognized in Other Comprehensive Income
Net actuarial loss during period	45	131	497
Amortization of actuarial loss	(79)	(64)	(27)
Prior service cost during period	11	0	12
Amortization to net income of net prior service credits	72	72	75
Total changes recognized in other comprehensive income	49	139	557
Recognized in Net Periodic Benefit Cost and Other Comprehensive Income	$ 221	$ 359	$ 723