Employee Benefit Plans (Net Periodic Benefit Costs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
United States Pension Plans of US Entity, Defined Benefit [Member]
Components of net periodic benefit costs
Service costs	$ 59	$ 56
Interest costs	97	101
Expected return on plan assets	(121)	(121)
Amortization of net actuarial (gains) losses	57	49
Amortization of prior service costs (credit)	3	2
Net periodic benefit costs	95	87
Foreign Pension Plans, Defined Benefit [Member]
Components of net periodic benefit costs
Service costs	17	20
Interest costs	4	4
Expected return on plan assets	(2)	(2)
Amortization of net actuarial (gains) losses	0	0
Amortization of prior service costs (credit)	0	0
Net periodic benefit costs	19	22
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Components of net periodic benefit costs
Service costs	5	5
Interest costs	23	26
Expected return on plan assets	(19)	(19)
Amortization of net actuarial (gains) losses	14	14
Amortization of prior service costs (credit)	(19)	(26)
Net periodic benefit costs	4	0
Foreign Postretirement Benefit Plans, Defined Benefit [Member]
Components of net periodic benefit costs
Service costs	0	0
Interest costs	1	1
Expected return on plan assets	0	0
Amortization of net actuarial (gains) losses	0	0
Amortization of prior service costs (credit)	0	0
Net periodic benefit costs	$ 1	$ 1