Derivative Instrument and Hedging Activities 3 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								6 Months Ended
	Jun. 30, 2012 Successor [Member]		Jun. 30, 2012 Successor [Member]		Mar. 25, 2012 Predecessor [Member]		Jun. 30, 2011 Predecessor [Member]		Jun. 30, 2011 Predecessor [Member]
Cash Flow Hedges: Interest rate contracts:
Change in fair value - increase in Accumulated other comprehensive income	$ 0	[1]	$ 0	[2]	$ 6,174	[2]	$ 18,478	[1]	$ 20,748	[2]
Reclassification of unrealized loss from Accumulated other comprehensive income - increase of Interest expense	0	[1]	0	[2]	8,085	[2]	5,615	[1]	11,166	[2]
Cash Flow Hedges: Commodity contracts - Gathering and Processing:
Change in fair value - increase/(decrease) in Accumulated other comprehensive income	9,591	[1]	11,377	[2]	4,619	[2]	(538)	[1]	1,014	[2]
Reclassification of unrealized gain from Accumulated other comprehensive income	5,536	[1]	5,536	[2]	2,043	[2]	4,655	[1]	9,184	[2]
Economic Hedges: Interest rate contracts: [Abstract]
Change in fair value - increase in interest expense	18,243		19,709		0		0		0
Economic Hedges: Commodity contracts - Gathering and Processing:
Change in fair value of hedges - decrease in Operating revenues	0						7,131
Change in fair value of other hedges - decrease in Operating revenues			0		50				23,648
Economic Hedges: Commodity contracts - Distribution:
Change in fair value - increase/(decrease) in Deferred natural gas purchases	$ (20,095)		$ (20,095)		$ (1,957)		$ (4,279)		$ (23,772)

[1] See Note 5 – Comprehensive Income (Loss) for related income tax amounts.

[2] The Company has master netting arrangements with certain of its counterparties, which permit applicable obligations of the parties to be settled on a net versus gross basis. If a right of offset exists, the fair value amounts for the derivative instruments are reported in the unaudited interim Condensed Consolidated Balance Sheet on a net basis and disclosed herein on a gross basis.