Derivatives And Risk Management (Schedule Of Derivative Instruments, Volumes Of Natural Gas Production) (Details) (Year 2015 [Member], Fixed Price Swaps [Member])	3 Months Ended
	Mar. 31, 2015 ft3
Derivative [Line Items]
Volume of natural gas production	181,000,000,000
Weighted average price to be swapped	4.40
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume of natural gas production	91,000,000,000
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume of natural gas production	90,000,000,000