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ASSET RETIREMENT OBLIGATION - Asset Retirement Obligation (Detail) (USD $)
In Millions, unless otherwise specified
3 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Dec. 31, 2011
Asset Retirement Obligations [Line Items]          
Asset retirement obligation at beginning of year     $ 3,887    
Liabilities incurred     383    
Liabilities acquired     33    
Liabilities settled     (418)    
Accretion expense 60 39 172 114  
Revisions in estimated liabilities     171    
Asset retirement obligation at September 30, 2012 4,228   4,228    
Less current portion (434)   (434)   (447)
Asset retirement obligation, long-term $ 3,794   $ 3,794   $ 3,440