Annual report pursuant to Section 13 and 15(d)

Reconciliation of the Changes in the Plans' Benefit Obligations and Fair Value of Plan Assets (Detail)

v2.4.0.6
Reconciliation of the Changes in the Plans' Benefit Obligations and Fair Value of Plan Assets (Detail) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Fair Value of Plan Assets:      
Ending Balance $ 22,837 $ 20,325  
U.S. Pension Benefits
      
Benefit Obligations:      
Projected benefit obligation at beginning of year 21,342 17,763  
Service cost 870 723 689
Interest cost 1,309 1,199 1,130
Gross benefits paid (657) (574)  
Plan amendments 3 (7)  
Actuarial (gain)/loss 1,519 2,238  
Projected benefit obligation at end of year 24,386 21,342 17,763
Fair Value of Plan Assets:      
Beginning Balance 20,092 15,351  
Actual return on plan assets 1,956 2,215  
Employer contributions 1,272 3,100  
Gross benefits paid (657) (574)  
Foreign currency exchange rate changes        
Ending Balance 22,663 20,092 15,351
U.S. Postretirement Medical Benefits
      
Benefit Obligations:      
Projected benefit obligation at beginning of year 3,597 3,336  
Service cost 89 86 85
Interest cost 207 214 211
Gross benefits paid (219) (207)  
Plan participants' contributions 16 17  
Plan amendments (24) 8  
Actuarial (gain)/loss 170 142  
Other   1  
Projected benefit obligation at end of year 3,836 3,597 3,336
Fair Value of Plan Assets:      
Beginning Balance 233 298  
Actual return on plan assets 9 30  
Employer contributions 108 95  
Plan participants' contributions 16 17  
Gross benefits paid (219) (207)  
Foreign currency exchange rate changes        
Other 27    
Ending Balance 174 233 298
International Pension Benefits
      
Benefit Obligations:      
Projected benefit obligation at beginning of year 680 575  
Service cost 34 24 17
Interest cost 39 34 28
Gross benefits paid (15) (13)  
Plan participants' contributions 1 1  
Plan amendments 7    
Actuarial (gain)/loss 99 58  
Foreign currency exchange rate changes (4) (4)  
Curtailments and settlements   (1)  
Other   6  
Projected benefit obligation at end of year 841 680 575
Fair Value of Plan Assets:      
Beginning Balance 561 481  
Actual return on plan assets 10 48  
Employer contributions 56 45  
Plan participants' contributions 1 1  
Gross benefits paid (15) (13)  
Foreign currency exchange rate changes        
Curtailments and settlements   (1)  
Ending Balance $ 613 $ 561 $ 481