Derivative Financial Instruments (Schedule Of Open Natural Gas Derivative Positions) (Details)	12 Months Ended
	Dec. 31, 2016 MMBTU $ / MMBTU
FERC Henry Hub Price Swaps Natural Gas Q1-Q4 2017 [Member]
Derivative [Line Items]
Volume Per Day (MMBtu/d) | MMBTU	189,753
Weighted Average Price Swap	3.13
FERC Henry Hub Price Swaps Natural Gas Q1-Q4 2018 [Member]
Derivative [Line Items]
Volume Per Day (MMBtu/d) | MMBTU	29,705
Weighted Average Price Swap	3.17
FERC Henry Hub Price Collars Natural Gas Q1-Q4 2017 [Member]
Derivative [Line Items]
Volume Per Day (MMBtu/d) | MMBTU	335,274
Weighted Average Floor Price	2.97
Weighted Average Ceiling Price	3.38
FERC Henry Hub Price Collars Natural Gas Q1-Q4 2018 [Member]
Derivative [Line Items]
Volume Per Day (MMBtu/d) | MMBTU	19,110
Weighted Average Floor Price	3.20
Weighted Average Ceiling Price	3.50
PEPL Basis Swaps Natural Gas Q1-Q4 2017 [Member]
Derivative [Line Items]
Volume Per Day (MMBtu/d) | MMBTU	150,000
Weighted Average Differential To Henry Hub	(0.34)
El Paso Natural Gas Basis Swaps Q1-Q4 2017 [Member]
Derivative [Line Items]
Volume Per Day (MMBtu/d) | MMBTU	80,000
Weighted Average Differential To Henry Hub	(0.13)
Houston Ship Channel Natural Gas Basis Swaps Q1-Q4 2017 [Member]
Derivative [Line Items]
Volume Per Day (MMBtu/d) | MMBTU	35,000
Weighted Average Differential To Henry Hub	0.06
Transco Zone 4 Natural Gas Basis Swaps Q1-Q4 2017 [Member]
Derivative [Line Items]
Volume Per Day (MMBtu/d) | MMBTU	205,000
Weighted Average Differential To Henry Hub	0.03
PEPL Basis Swaps Natural Gas Q1 2018 [Member]
Derivative [Line Items]
Volume Per Day (MMBtu/d) | MMBTU	50,000
Weighted Average Differential To Henry Hub	(0.29)