Derivatives And Risk Management (Summary Of Before Tax Effect Of Cash Flow Hedges On Consolidated Financial Statements) (Details) (Fixed Price Swaps [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Derivative [Line Items]
Derivative Instruments, Loss Recognized in Other Comprehensive Income, Effective Portion	$ (90,334)	$ (73,902)
Gas Sales [Member]
Derivative [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated Other Comprehensive Income into Earnings, Effective Portion	(41,978)	78,621
Derivative Instruments, Gain (Loss) Recognized in Earnings, Ineffective Portion	$ (1,940)	$ 1,301