Employee Benefit Plans (Details 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
United States Pension Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	$ 0	$ 0	$ 0
Defined Benefit Plan, Interest Cost	969	982	1,002
Defined Benefit Plan, Expected Return on Plan Assets	(724)	(677)	(615)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0	0
Defined Benefit Plan, Amortization of Gains (Losses)	55	48	33
Defined Benefit Plan, Recognized Net (Gain) Loss Due to Settlements	0	14	9
Defined Benefit Plan, Other Costs	0	0	0
Defined Benefit Plan, Net Periodic Benefit Cost	300	367	429
Defined Contribution Plan, Cost Recognized	377	334	306
Defined Benefit Plan Cost Benefit	677	701	735
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	52	58	53
Defined Benefit Plan, Interest Cost	180	196	207
Defined Benefit Plan, Expected Return on Plan Assets	(90)	(90)	(79)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	(3)	(4)	18
Defined Benefit Plan, Amortization of Gains (Losses)	(11)	(4)	(18)
Defined Benefit Plan, Recognized Net (Gain) Loss Due to Settlements	0	0	0
Defined Benefit Plan, Other Costs	0	0	6
Defined Benefit Plan, Net Periodic Benefit Cost	128	156	187
Defined Contribution Plan, Cost Recognized	0	0	0
Defined Benefit Plan Cost Benefit	$ 128	$ 156	$ 187