DERIVATIVES (Narrative) (Details) - bbl	Mar. 31, 2020	Dec. 31, 2019
Crude Oil and Feedstock Inventory [Member] | Fair Value Hedging [Member]
Derivative [Line Items]
Derivative, notional amount, volume	0	27,580
Intermediates and Refined Products Inventory [Member] | Fair Value Hedging [Member]
Derivative [Line Items]
Derivative, notional amount, volume	3,275,153	3,430,635
Crude Oil Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, notional amount, volume	3,500,000	5,511,000
Refined Product Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, notional amount, volume	2,775,000	5,788,000