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ASSET RETIREMENT OBLIGATION - Schedule of changes to Asset Retirement Obligation (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Asset retirement obligation at beginning of year $ 2,498 $ 2,598
Liabilities incurred 58 41
Liabilities divested (818) (7)
Liabilities settled (45) (57)
Accretion expense 130 156
Revisions in estimated liabilities 12 (233)
Asset retirement obligation at end of year 1,835 2,498
Less current portion (43) (66)
Asset retirement obligation, long-term $ 1,792 $ 2,432