Employee Benefit Plans (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
United States Pension Plans of US Entity, Defined Benefit [Member]
Components of net periodic benefit costs
Service costs	$ 224	$ 187	$ 172
Interest costs	406	404	393
Settlement and curtailment costs	0	0	0
Expected return on plan assets	(484)	(448)	(444)
Amortization of net actuarial (gains) losses	195	194	196
Amortization of prior service costs (credit)	6	4	7
Net periodic benefit costs	347	341	324
Foreign Pension Plans, Defined Benefit [Member]
Components of net periodic benefit costs
Service costs	75	64	8
Interest costs	17	16	6
Settlement and curtailment costs	0	0	8
Expected return on plan assets	(6)	(6)	(6)
Amortization of net actuarial (gains) losses	0	0	0
Amortization of prior service costs (credit)	0	0	0
Net periodic benefit costs	86	74	16
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Components of net periodic benefit costs
Service costs	21	16	16
Interest costs	103	106	111
Settlement and curtailment costs	0	0	0
Expected return on plan assets	(77)	(76)	(79)
Amortization of net actuarial (gains) losses	57	43	38
Amortization of prior service costs (credit)	(104)	(108)	(83)
Net periodic benefit costs	0	(19)	3
Foreign Postretirement Benefit Plans, Defined Benefit [Member]
Components of net periodic benefit costs
Service costs	1	1	1
Interest costs	2	2	2
Settlement and curtailment costs	1	1	1
Expected return on plan assets	(1)	(1)	0
Amortization of net actuarial (gains) losses	0	0	0
Amortization of prior service costs (credit)	0	0	0
Net periodic benefit costs	$ 3	$ 3	$ 4