Employee Benefits (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
Net Periodic Benefit Cost
Net Periodic Benefit Costs	$ 342		$ 338		$ 1,038		$ 1,032
U.S. [Member]
Net Periodic Benefit Cost
Service cost	124		113		371		339
Interest cost	117		109		353		327
Expected return on plan assets	(175)		(158)		(525)		(475)
Amortization of prior service costs (credits)	0		(2)		1		(6)
Amortization of actuarial losses	121		117		364		352
Settlement losses (gains)	57		65		171		204
Net Periodic Benefit Costs	244		244		735		741
International [Member]
Net Periodic Benefit Cost
Service cost	48		45		145		135
Interest cost	77		79		236		241
Expected return on plan assets	(68)		(67)		(204)		(201)
Amortization of prior service costs (credits)	6		5		16		14
Amortization of actuarial losses	35		32		110		102
Net Periodic Benefit Costs	98		94		303		291
Other Benefits [Member]
Net Periodic Benefit Cost
Service cost	13	[1]	16	[1]	49	[1]	46	[1]
Interest cost	32	[1]	37	[1]	112	[1]	114	[1]
Amortization of prior service costs (credits)	(12)	[1]	(18)	[1]	(37)	[1]	(54)	[1]
Amortization of actuarial losses	13	[1]	13	[1]	40	[1]	42	[1]
Settlement losses (gains)	0	[1]	0	[1]	0	[1]	(26)	[1]
Net Periodic Benefit Costs	$ 46		$ 48		$ 164		$ 122

[1] Includes costs for U.S. and international OPEB plans. Obligations for plans outside the United States are not significant relative to the company’s total OPEB obligation.