Pension and Other Postretirement Employee Benefit Plans - Estimated Future Benefit Payments (Details 11) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Defined Benefit Pension Plans, U.S. [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	$ 1,159
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	1,162
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	705
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	709
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	711
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	3,555
Foreign Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	102
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	101
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	108
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	110
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	112
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	626
Other Postretirement Benefit Plans, Excluding Prescription Drug Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	92
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	91
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	89
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	87
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	84
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	376
Other Postretirement Benefit Plans, Including Prescription Drug Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months	11
Defined Benefit Plan, Expected Future Benefit Payments, Year Two	12
Defined Benefit Plan, Expected Future Benefit Payments, Year Three	13
Defined Benefit Plan, Expected Future Benefit Payments, Year Four	14
Defined Benefit Plan, Expected Future Benefit Payments, Year Five	14
Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter	$ 65