DERIVATIVES (Narrative) (Details) - bbl	Mar. 31, 2019	Dec. 31, 2018
Crude Oil and Feedstock Inventory [Member] | Fair Value Hedging [Member]
Derivative [Line Items]
Derivative, notional amount, volume	754,419	0
Intermediates and Refined Products Inventory [Member] | Fair Value Hedging [Member]
Derivative [Line Items]
Derivative, notional amount, volume	3,232,956	3,350,166
Crude Oil Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, notional amount, volume	6,558,000	5,801,000
Refined Product Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, notional amount, volume	4,904,000	1,609,000