Derivatives (Non-Qualifying Cash Flow Derivatives Outstanding) (Details) (Basis Swap [Member], Natural Gas [Member], Oct'11 - Dec'11 [Member], USD $)	9 Months Ended
	Sep. 30, 2011
CEGT - NYMEX [Member]
Hedged Volume (MMBtu/day)	10,000
Basis Differential	$ (0.21)
CEGT - NYMEX [Member] | Start [Member]
Commodity Derivatives Term	Oct'11
CEGT - NYMEX [Member] | End [Member]
Commodity Derivatives Term	Dec'11
PEPL - NYMEX [Member]
Hedged Volume (MMBtu/day)	10,000
Basis Differential	(0.23)
PEPL - NYMEX [Member] | Start [Member]
Commodity Derivatives Term	Oct'11
PEPL - NYMEX [Member] | End [Member]
Commodity Derivatives Term	Dec'11
Tenn Zone - NYMEX [Member]
Hedged Volume (MMBtu/day)	15,000
Basis Differential	$ (0.14)
Tenn Zone - NYMEX [Member] | Start [Member]
Commodity Derivatives Term	Oct'11
Tenn Zone - NYMEX [Member] | End [Member]
Commodity Derivatives Term	Dec'11