DERIVATIVES (Narrative) (Details) - bbl	Mar. 31, 2021	Dec. 31, 2020
Crude Oil and Feedstock Inventory [Member] | Fair Value Hedging [Member]
Derivative [Line Items]
Derivative, notional amount, volume	0	0
Intermediates and Refined Products Inventory [Member] | Fair Value Hedging [Member]
Derivative [Line Items]
Derivative, notional amount, volume	2,306,301	2,604,736
Crude Oil Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, notional amount, volume	18,975,000	7,183,000
Refined Product Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, notional amount, volume	3,138,000	2,810,000