Employee Benefit Plans (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Pension and Other Postretirement Defined Benefit Plans, Liabilities [Abstract]
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	$ (12,392)	$ (16,005)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, [Abstract]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	(5,300)	(8,200)
United States Pension Plans of US Entity, Defined Benefit [Member]
Pension and Other Postretirement Defined Benefit Plans, Liabilities [Abstract]
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	(22)	(24)
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	(10,101)	(13,269)
Pension and Other Postretirement Defined Benefit Plans, Liabilities	(10,123)	(13,293)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, [Abstract]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	(5,349)	(7,958)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	0	0
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	(5,349)	(7,958)
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Pension and Other Postretirement Defined Benefit Plans, Liabilities [Abstract]
Pension and Other Postretirement Defined Benefit Plans, Current Liabilities	(139)	(132)
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	(2,023)	(2,446)
Pension and Other Postretirement Defined Benefit Plans, Liabilities	(2,162)	(2,578)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Adjustment, before Tax, [Abstract]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax	(103)	(473)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax	161	187
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	$ 58	$ (286)