v2.4.0.6
Employee Benefit Plans - Sources of Change in Other Comprehensive Income (Detail) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Sources of Change in Other Comprehensive Income      
Net gain (loss) arising during the period $ (1,185) $ (9) $ (388)
Amortization of (gain) loss included in income 226 215 206
Prior service (cost) credit arising during the period (19) 13  
Amortization of prior service cost (credit) included in income (2) (15) (21)
U.S. (Pension Benefits) [Member]
      
Sources of Change in Other Comprehensive Income      
Net gain (loss) arising during the period (858) (70)  
Amortization of (gain) loss included in income 185 167  
Net change during the period (673) 97  
Prior service (cost) credit arising during the period   (12)  
Amortization of prior service cost (credit) included in income 9 10  
Net change during the period 9 (2)  
Int'l (Pension Benefits) [Member]
      
Sources of Change in Other Comprehensive Income      
Net gain (loss) arising during the period (307) 75  
Amortization of (gain) loss included in income 46 55  
Net change during the period (261) 130  
Prior service (cost) credit arising during the period 53 (1)  
Amortization of prior service cost (credit) included in income   2  
Net change during the period 53 1  
Other Benefits [Member]
      
Sources of Change in Other Comprehensive Income      
Net gain (loss) arising during the period (20) (14)  
Amortization of (gain) loss included in income (5) (7)  
Net change during the period (25) (21)  
Prior service (cost) credit arising during the period (34)    
Amortization of prior service cost (credit) included in income (7) 3  
Net change during the period $ (41) $ 3