Derivatives And Risk Management (Schedule Of Derivative Instruments, Volumes Of Natural Gas Production) (Details) (Fixed Price Swaps [Member])	3 Months Ended
	Mar. 31, 2014 ft3
Year 2014 [Member]
Derivative [Line Items]
Volume of natural gas production	348,600,000,000
Year 2014 [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume of natural gas production	211,800,000,000
Year 2014 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume of natural gas production	136,800,000,000
Year 2015 [Member]
Derivative [Line Items]
Volume of natural gas production	119,500,000,000
Year 2015 [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume of natural gas production	119,500,000,000