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DESCRIPTION OF BUSINESS (Details)
$ in Millions
12 Months Ended
Dec. 31, 2019
segment
Jan. 01, 2020
USD ($)
Subsequent Event [Line Items]    
Number of operating units | segment 2  
Disposed of by Sale | Upstream Assets | Subsequent Event    
Subsequent Event [Line Items]    
Unadjusted purchase price   $ 232.0
Disposed of by Sale | Midstream Assets | Subsequent Event    
Subsequent Event [Line Items]    
Unadjusted purchase price   $ 88.0