Revenue Recognition (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Contract asset associated with revenues from contracts with customers		$ 0
Contract liability associated with revenues from contracts with customers		$ 0
Fayetteville Shale
Disaggregation of Revenue [Line Items]
Percentage of assets sold	100.00%
Natural gas and liquids | Minimum
Disaggregation of Revenue [Line Items]
Revenue payment terms		30 days
Natural gas and liquids | Maximum
Disaggregation of Revenue [Line Items]
Revenue payment terms		60 days
Marketing | Minimum
Disaggregation of Revenue [Line Items]
Revenue payment terms		30 days
Marketing | Maximum
Disaggregation of Revenue [Line Items]
Revenue payment terms		60 days
Gas gathering | Minimum
Disaggregation of Revenue [Line Items]
Revenue payment terms		30 days
Gas gathering | Maximum
Disaggregation of Revenue [Line Items]
Revenue payment terms		60 days