Derivatives And Risk Management (Schedule Of Derivative Instruments, Volumes Of Natural Gas Production) (Details) (Year 2015 [Member])	12 Months Ended
	Dec. 31, 2014 ft3
Derivative [Line Items]
Volume of natural gas production	240,000,000,000
Weighted average price to be swapped	4.40
Fixed Price Swaps [Member]
Derivative [Line Items]
Volume of natural gas production	120,000,000,000
Fixed Price Swaps [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume of natural gas production	120,000,000,000