Annual report pursuant to Section 13 and 15(d)

Amounts in AOCI Expected to be Amortized and Recognized as a Component of Net Periodic Benefit Cost (Detail)

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Amounts in AOCI Expected to be Amortized and Recognized as a Component of Net Periodic Benefit Cost (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2011
U.S. Pension Benefits
 
Defined Benefit Plan Disclosure [Line Items]  
Prior service cost / (benefit) $ 173
U.S. Postretirement Medical Benefits
 
Defined Benefit Plan Disclosure [Line Items]  
Prior service cost / (benefit) 5
International Pension Benefits
 
Defined Benefit Plan Disclosure [Line Items]  
Prior service cost / (benefit) $ 2