Counterparties representing 10% or more (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Liabilities from price risk management activities: [Abstract]
Concentration of Risk, Derivative Instruments, Assets	71.00%	77.00%
Counterparty A [Member]
Liabilities from price risk management activities: [Abstract]
Concentration Risk, Percentage	35.00%	42.00%
Counterparty B [Member]
Liabilities from price risk management activities: [Abstract]
Concentration Risk, Percentage	1.00%	15.00%
Counterparty C [Member]
Liabilities from price risk management activities: [Abstract]
Concentration Risk, Percentage	13.00%	5.00%
Counterparty D [Member]
Liabilities from price risk management activities: [Abstract]
Concentration Risk, Percentage	11.00%	6.00%
Counterparty E [Member]
Liabilities from price risk management activities: [Abstract]
Concentration Risk, Percentage	11.00%	9.00%
Counterparty F [Member]
Liabilities from price risk management activities: [Abstract]
Concentration Risk, Percentage	79.00%	56.00%