Employee Benefit Plans (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Changes Recognized in Comprehensive Income
Prior service (credits) costs during period	$ (6)	$ 6	$ (60)
Amortization of prior service (costs) credits	(30)	(26)	27
U.S. [Member]
Net Periodic Benefit Cost
Service cost	538	450	495
Interest cost	502	494	471
Expected return on plan assets	(783)	(788)	(701)
Amortization of prior service costs (credits)	(8)	(9)	2
Recognized actuarial losses	356	209	485
Settlement losses	320	237	173
Curtailment losses (gains)	0	0	0
Total net periodic benefit cost	925	593	925
Changes Recognized in Comprehensive Income
Net actuarial (gain) loss during period	513	2,233	(2,244)
Amortization of actuarial loss	(676)	(446)	(658)
Prior service (credits) costs during period	0	0	(78)
Amortization of prior service (costs) credits	8	9	(2)
Total changes recognized in other comprehensive income	(155)	1,796	(2,982)
Recognized in Net Periodic Benefit Cost and Other Comprehensive Income	770	2,389	(2,057)
International [Member]
Net Periodic Benefit Cost
Service cost	185	190	197
Interest cost	277	340	314
Expected return on plan assets	(262)	(298)	(274)
Amortization of prior service costs (credits)	22	21	21
Recognized actuarial losses	78	96	143
Settlement losses	6	208	12
Curtailment losses (gains)	(14)	0	0
Total net periodic benefit cost	292	557	413
Changes Recognized in Comprehensive Income
Net actuarial (gain) loss during period	(260)	(17)	(476)
Amortization of actuarial loss	(84)	(304)	(155)
Prior service (credits) costs during period	(6)	4	18
Amortization of prior service (costs) credits	(24)	(21)	(21)
Total changes recognized in other comprehensive income	(374)	(338)	(634)
Recognized in Net Periodic Benefit Cost and Other Comprehensive Income	(82)	219	(221)
Other Benefits [Member]
Net Periodic Benefit Cost
Service cost	72	50	66
Interest cost	151	148	149
Expected return on plan assets	0	0	0
Amortization of prior service costs (credits)	14	14	(50)
Recognized actuarial losses	34	7	53
Settlement losses	0	0	0
Curtailment losses (gains)	0	0	0
Total net periodic benefit cost	271	219	218
Changes Recognized in Comprehensive Income
Net actuarial (gain) loss during period	(362)	514	(659)
Amortization of actuarial loss	(34)	(7)	(53)
Prior service (credits) costs during period	0	2	0
Amortization of prior service (costs) credits	(14)	(14)	50
Total changes recognized in other comprehensive income	(410)	495	(662)
Recognized in Net Periodic Benefit Cost and Other Comprehensive Income	$ (139)	$ 714	$ (444)