Employee Benefit Plans (Details 5) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
United States Pension Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	$ 1,141
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	1,136
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	1,149
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	1,164
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	1,181
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	6,153
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Defined Benefit Plan, Expected Future Benefit Payments in Year One	275
Defined Benefit Plan, Expected Future Benefit Payments in Year Two	276
Defined Benefit Plan, Expected Future Benefit Payments in Year Three	276
Defined Benefit Plan, Expected Future Benefit Payments in Year Four	274
Defined Benefit Plan, Expected Future Benefit Payments in Year Five	270
Defined Benefit Plan, Expected Future Benefit Payments in Five Fiscal Years Thereafter	$ 1,293