Derivatives Derivatives (2-1-1 Crack Spread Swap sales) (Details) - Fuel Product - Not Designated as Hedging Instrument - 2-1-1 Crack Spread Swap	Dec. 31, 2019 bbl $ / bbl	Dec. 31, 2018 bbl
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	394,000	0
Average Swap ($/Bbl) | $ / bbl	17.58
First Quarter 2020 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	364,000
Barrels per Day Sold	4,000
Average Swap ($/Bbl) | $ / bbl	17.43
Second Quarter 2020 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	30,000
Barrels per Day Sold	330
Average Swap ($/Bbl) | $ / bbl	19.50