Derivatives And Risk Management (Fixed Price Swaps, Volumes of Natural Gas Production (in Bcf)) (Details) (Year 2014 [Member])	Dec. 31, 2013 ft3
Derivative [Line Items]
Volume of Natural Gas Production (in Bcf), Fixed Price Swaps	382,300,000,000
Fixed and Floating Price Swaps [Member]
Derivative [Line Items]
Volume of Natural Gas Production (in Bcf), Fixed Price Swaps	200,700,000,000
Fixed and Floating Price Swaps [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Volume of Natural Gas Production (in Bcf), Fixed Price Swaps	181,600,000,000