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ASSET RETIREMENT OBLIGATION (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]    
Asset retirement obligation at the beginning of period $ 1,835  
Liabilities incurred 7  
Liabilities settled (8)  
Accretion expense 27  
Asset retirement obligation at the end of period 1,861  
Less current portion (42) $ (43)
Asset retirement obligation, long-term $ 1,819 $ 1,792