Counterparties representing 10% or more (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Liabilities from price risk management activities: [Abstract]
Concentration of Risk, Derivative Instruments, Assets	66.00%	70.00%
Counterparty A [Member]
Liabilities from price risk management activities: [Abstract]
Concentration Risk, Percentage	12.00%	35.00%
Counterparty B [Member]
Liabilities from price risk management activities: [Abstract]
Concentration Risk, Percentage	17.00%	13.00%
Counterparty C [Member]
Liabilities from price risk management activities: [Abstract]
Concentration Risk, Percentage	21.00%	11.00%
Counterparty D [Member]
Liabilities from price risk management activities: [Abstract]
Concentration Risk, Percentage	16.00%	11.00%
Counterparty F [Member]
Liabilities from price risk management activities: [Abstract]
Concentration Risk, Percentage	93.00%	79.00%