Derivatives Derivatives (WCS Crude Oil Basis Swaps Sales) (Details) - Fuel Product - Not Designated as Hedging Instrument - WCS Crude Oil Basis Swaps Sales [Member]	Dec. 31, 2019 bbl	Dec. 31, 2018 bbl $ / bbl
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	1,763,000
Average Swap ($/Bbl) | $ / bbl		(19.84)
First Quarter 2019 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		388,000
Barrels per Day Sold		4,311
Average Swap ($/Bbl) | $ / bbl		(19.84)
Second Quarter 2019 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		455,000
Barrels per Day Sold		5,000
Average Swap ($/Bbl) | $ / bbl		(19.84)
Third Quarter 2019 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		460,000
Barrels per Day Sold		5,000
Average Swap ($/Bbl) | $ / bbl		(19.84)
Fourth Quarter 2019 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		460,000
Barrels per Day Sold		5,000
Average Swap ($/Bbl) | $ / bbl		(19.84)