Derivatives Derivatives (WCS Crude Oil Percent Basis Swaps) (Details) - Fuel Product - Not Designated as Hedging Instrument - WCS Crude Oil Percentage Basis Swaps - bbl	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	1,825,000
Derivative, Fixed Percentage to Publicly Traded Future		66.32%
First Quarter 2019 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		450,000
Barrels per Day Purchased		5,000
Derivative, Fixed Percentage to Publicly Traded Future		66.32%
Second Quarter 2019 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		455,000
Barrels per Day Purchased		5,000
Derivative, Fixed Percentage to Publicly Traded Future		66.32%
Third Quarter 2019 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		460,000
Barrels per Day Purchased		5,000
Derivative, Fixed Percentage to Publicly Traded Future		66.32%
Fourth Quarter 2019 [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount		460,000
Barrels per Day Purchased		5,000
Derivative, Fixed Percentage to Publicly Traded Future		66.32%