Employee Benefit Plans (Details 4) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net Periodic Benefit Cost Amortized From Accumulated Other Comprehensive Income (Loss)
Total recognized in other comprehensive income (loss)	$ 842	$ 760	$ (165)
United States Pension Plans of US Entity, Defined Benefit [Member]
Net Periodic Benefit Cost Amortized From Accumulated Other Comprehensive Income (Loss)
Net actuarial (gains) losses	744	575	37
Prior service costs (credit)	0	17	0
Amortization of net actuarial gains (losses)	(195)	(194)	(196)
Amortization of prior service (costs) credit	(6)	(4)	(7)
Total recognized in other comprehensive income (loss)	543	394	(166)
Total recognized in net periodic benefit costs and other comprehensive income (loss)	890	735	158
Foreign Pension Plans, Defined Benefit [Member]
Net Periodic Benefit Cost Amortized From Accumulated Other Comprehensive Income (Loss)
Net actuarial (gains) losses	18	34	(15)
Prior service costs (credit)	(1)	0	1
Amortization of net actuarial gains (losses)	0	0	0
Amortization of prior service (costs) credit	0	0	0
Total recognized in other comprehensive income (loss)	17	34	(14)
Total recognized in net periodic benefit costs and other comprehensive income (loss)	103	108	2
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Net Periodic Benefit Cost Amortized From Accumulated Other Comprehensive Income (Loss)
Net actuarial (gains) losses	234	262	49
Prior service costs (credit)	0	0	(81)
Amortization of net actuarial gains (losses)	(57)	(43)	(38)
Amortization of prior service (costs) credit	104	108	83
Total recognized in other comprehensive income (loss)	281	327	13
Total recognized in net periodic benefit costs and other comprehensive income (loss)	281	308	16
Foreign Postretirement Benefit Plans, Defined Benefit [Member]
Net Periodic Benefit Cost Amortized From Accumulated Other Comprehensive Income (Loss)
Net actuarial (gains) losses	2	5	1
Prior service costs (credit)	(1)	0	1
Amortization of net actuarial gains (losses)	0	0	0
Amortization of prior service (costs) credit	0	0	0
Total recognized in other comprehensive income (loss)	1	5	2
Total recognized in net periodic benefit costs and other comprehensive income (loss)	$ 4	$ 8	$ 6