Employee Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Net Periodic Benefit Cost
Net Periodic Benefit Costs	$ 343		$ 348
U.S. [Member]
Net Periodic Benefit Cost
Service cost	124		113
Interest cost	118		109
Expected return on plan assets	(175)		(159)
Amortization of prior service costs (credits)	0		(2)
Amortization of actuarial losses	121		118
Settlement losses (gains)	57		74
Net Periodic Benefit Costs	245		253
International [Member]
Net Periodic Benefit Cost
Service cost	48		44
Interest cost	77		79
Expected return on plan assets	(68)		(66)
Amortization of prior service costs (credits)	5		5
Amortization of actuarial losses	36		33
Net Periodic Benefit Costs	98		95
Other Benefits [Member]
Net Periodic Benefit Cost
Service cost	18	[1]	15	[1]
Interest cost	40	[1]	39	[1]
Amortization of prior service costs (credits)	(12)	[1]	(18)	[1]
Amortization of actuarial losses	13	[1]	15	[1]
Settlement losses (gains)	0	[1]	(26)	[1]
Net Periodic Benefit Costs	$ 59		$ 25

[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.