v2.4.0.8
Change In Benefit Obligations Change In Plan Assets Funded Status Amounts Recognized On Balance Sheet And Amounts Recognized In Accumulated Other Comprehensive Loss Pretax (Detail) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]      
End of year $ 3,053 $ 2,657  
Noncurrent liabilities (27,682) (34,346)  
Pension
      
Defined Benefit Plan Disclosure [Line Items]      
Beginning of year 26,773 30,582  
Service cost 395 358 307
Interest cost 1,002 1,449 1,590
Plan amendments (149) 183  
Actuarial (gain) loss, net (2,327) 6,074  
Benefits paid (1,777) (2,735)  
Curtailment and termination benefits 4    
Annuity purchase   (8,352)  
Settlements paid (889) (786)  
End of year 23,032 26,773 30,582
Beginning of year 18,282 24,110  
Actual return on plan assets 1,388 2,326  
Company contributions 107 3,719  
Benefits paid (1,777) (2,735)  
Settlements paid (889) (786)  
Annuity purchase   (8,352)  
End of year 17,111 18,282 24,110
End of year (5,921) (8,491)  
Noncurrent assets 339 236  
Current liabilities (137) (129)  
Noncurrent liabilities (6,123) (8,598)  
Total (5,921) (8,491)  
Prior Service Benefit (Cost) 25 181  
Total 25 181  
Health Care And Life
      
Defined Benefit Plan Disclosure [Line Items]      
Beginning of year 26,844 27,369  
Service cost 318 359 299
Interest cost 1,095 1,284 1,421
Plan amendments (119) (1,826)  
Actuarial (gain) loss, net (3,576) 1,402  
Benefits paid (1,520) (1,744)  
End of year 23,042 26,844 27,369
Beginning of year 2,657 2,628  
Actual return on plan assets 556 312  
Company contributions 1,360 1,461  
Benefits paid (1,520) (1,744)  
End of year 3,053 2,657 2,628
End of year (19,989) (24,187)  
Current liabilities (710) (766)  
Noncurrent liabilities (19,279) (23,421)  
Total (19,989) (24,187)  
Prior Service Benefit (Cost) (2,120) (2,247)  
Total $ (2,120) $ (2,247)