DERIVATIVES AND RISK MANAGEMENT ACTIVITIES Narrative (Details) bbl in Millions |
1 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
|
Jun. 30, 2018
USD ($)
bbl
|
Dec. 31, 2017
USD ($)
bbl
|
Apr. 30, 2018
USD ($)
|
Jun. 30, 2018
USD ($)
|
Apr. 15, 2018 |
|
| Derivative [Line Items] | |||||
| Cash received from termination of interest rate swaps | $ 8,000,000 | ||||
| Margin deposit | $ 200,000 | $ 300,000 | $ 200,000 | ||
| Interest rate swaps | Cash Flow Hedges | |||||
| Derivative [Line Items] | |||||
| Interest rate swaps interest rate received | receive a rate based on the three-month USD LIBOR | ||||
| Notional amount of forward-starting interest rate swaps | $ 250,000,000 | $ 600,000,000 | $ 250,000,000 | ||
| Notional amount of forward-starting interest rate swaps terminated | $ 350,000,000 | ||||
| Commodity contracts | |||||
| Derivative [Line Items] | |||||
| Notional amount of commodity contracts, volume (in barrels) | bbl | 1.2 | 1.2 | |||
| Logistics Notes due 2018 [Member] | |||||
| Derivative [Line Items] | |||||
| Stated interest rate | 7.65% |