Derivatives (Schedule Of Subsequent Non-designated Hedges) (Details) (Not Designated as Hedging Instrument [Member], Subsequent to December 31, 2013 [Member], Mar'14 [Member], Natural Gas [Member], Basis Swap [Member])	12 Months Ended
	Dec. 31, 2013 MMBTU Unit
NGPL-TXOK [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (MMBtu/day)	30,000
Weighted Average Fixed Price for Swaps	(0.095)
NGPL-Midcon [Member] [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (MMBtu/day)	60,000
Weighted Average Fixed Price for Swaps	(0.027)
Start [Member] | NGPL-TXOK [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Commodity Derivatives Term	Mar'14
Start [Member] | NGPL-Midcon [Member] [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Commodity Derivatives Term	Mar'14
End [Member] | NGPL-TXOK [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Commodity Derivatives Term	Mar'14
End [Member] | NGPL-Midcon [Member] [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Commodity Derivatives Term	Mar'14