Pension and Other Employee Benefits (Narrative) (Details) (USD $)
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Defined Contribution Plan, Cost Recognized $ 272,000,000 $ 273,000,000 $ 275,000,000
Amount invested in defined contribution plan 12,100,000,000 11,000,000,000  
Contractual pension benefit agreements liability 36,000,000 35,000,000  
Accumulated Benefit Obligation (ABO) 22,288,000,000 19,532,000,000  
PBO - Pension plans with PBO in excess of plan assets 24,657,000,000 21,592,000,000  
Fair value of plan assets - Pension plans with PBO in excess of plan assets 17,450,000,000 15,529,000,000  
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Accumulated Benefit Obligation 22,252,000,000 19,464,000,000  
Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets 17,411,000,000 15,481,000,000  
Discount rate - Domestic Pension Benefits 4.15% 5.00%  
Estimated assumed annual return on assets 8.75%    
Long-term actual annual rate of return - domestic pension 12.00% (1.00%) 11.00%
Effect of a 1% increase in assumed health care trend rate - accumulated postretirement benefit obligation 10,000,000    
Effect of a 1% decrease in assumed health care trend rate - accumulated postretirement benefit obligation (9,000,000)    
Defined Benefit Plan Plan Assets Invested In Three Indices 3,000,000,000    
Payable for securities lending collateral 15,000,000 63,000,000  
Net receivables and payables 192,000,000 89,000,000  
Domestic Pension Plan [Member]
      
Estimated assumed annual return on assets 8.75%    
Level 1 [Member]
      
Cash on deposit for future margin requirements 6,000,000 8,000,000  
Fair Value, Inputs, Level 3 [Member]
      
Fair value of Company's plan assets 1,169,000,000 752,000,000 627,000,000
Defined Benefit Plan, Actual Return on Plan Assets Still Held 32,000,000 (1,000,000)  
Pension Plans [Member]
      
Required contributions to pension plans expected 775,000,000    
Other Postretirement Benefit Plans [Member]
      
Required contributions to pension plans expected 25,000,000    
Other Benefits [Member]
      
Fair value of Company's plan assets 408,000,000 396,000,000  
Assets invested in Master Trust 179,000,000 172,000,000  
Stock Fund [Member]
      
Amount invested in defined contribution plan 1,000,000,000 1,100,000,000  
Domestic Pension Plan [Member]
      
Fair value of Company's plan assets 16,733,000,000 14,931,000,000  
Defined Benefit Plan, Benefit Obligation 23,836,000,000 20,905,000,000  
Domestic Pension Plan [Member] | Level 1 [Member]
      
Fair value of Company's plan assets 6,575,000,000 6,772,000,000  
Domestic Pension Plan [Member] | Fair Value, Inputs, Level 3 [Member]
      
Fair value of Company's plan assets 1,169,000,000 752,000,000  
Required Contributions [Member]
      
Pension and Other Postretirement Benefit Contributions 740,000,000 1,096,000,000 1,184,000,000
Foreign Pension Plan [Member]
      
Fair value of Company's plan assets 717,000,000 621,000,000  
Defined Benefit Plan, Net Periodic Benefit Cost 7,000,000 11,000,000 21,000,000
Defined Benefit Plan, Benefit Obligation 821,000,000 708,000,000  
Discretionary Contributions [Member]
      
Pension and Other Postretirement Benefit Contributions 500,000,000 750,000,000 750,000,000
Domestic Qualified Pension Plan [Member]
      
Fair value of Company's plan assets 16,733,000,000 14,931,000,000  
Defined Benefit Plan, Benefit Obligation 23,082,000,000 20,290,000,000  
Accumulated Benefit Obligation (ABO) 20,828,000,000 18,302,000,000  
Minimum [Member]
      
Percent company matches of employees contributions 3.00%    
Maximum [Member]
      
Percent company matches of employees contributions 4.00%    
Effect of a 1% increase in assumed health care trend rate - aggregate of service and interest cost 1,000,000    
Defined Benefit Plan Percent Of Plan Assets That Do Not Track An Index 10.00%    
FMV of Plan's derivatives upper limit $ 1,000,000 $ 1,000,000