Pension and Other Employee Benefits (Adjustment to Accumulated Other Comprehensive Loss) (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Defined Pension Benefits [Member]
 
Amortization of net loss $ (1,169)
Amortization of transition obligation 0
Amortization of prior service (cost) credit (9)
Total (1,178)
Other Benefits [Member]
 
Amortization of net loss (4)
Amortization of transition obligation 0
Amortization of prior service (cost) credit 3
Total $ (1)