Reportable Segments 1 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2012 Successor [Member]	Sep. 30, 2012 Successor [Member]	Sep. 30, 2012 Successor [Member] Transportation and Storage [Member]	Sep. 30, 2012 Successor [Member] Transportation and Storage [Member]	Sep. 30, 2012 Successor [Member] Gathering and Processing [Member]	Sep. 30, 2012 Successor [Member] Gathering and Processing [Member]	Sep. 30, 2012 Successor [Member] Distribution [Member]	Sep. 30, 2012 Successor [Member] Distribution [Member]	Sep. 30, 2012 Successor [Member] Total segment [Member]	Sep. 30, 2012 Successor [Member] Total segment [Member]	Sep. 30, 2012 Successor [Member] Corporate and other activities [Member]	Sep. 30, 2012 Successor [Member] Corporate and other activities [Member]	Mar. 25, 2012 Predecessor [Member]	Sep. 30, 2011 Predecessor [Member]	Sep. 30, 2011 Predecessor [Member]	Dec. 31, 2011 Predecessor [Member]	Mar. 25, 2012 Predecessor [Member] Transportation and Storage [Member]	Sep. 30, 2011 Predecessor [Member] Transportation and Storage [Member]	Sep. 30, 2011 Predecessor [Member] Transportation and Storage [Member]	Dec. 31, 2011 Predecessor [Member] Transportation and Storage [Member]	Mar. 25, 2012 Predecessor [Member] Gathering and Processing [Member]	Sep. 30, 2011 Predecessor [Member] Gathering and Processing [Member]	Sep. 30, 2011 Predecessor [Member] Gathering and Processing [Member]	Dec. 31, 2011 Predecessor [Member] Gathering and Processing [Member]	Mar. 25, 2012 Predecessor [Member] Distribution [Member]	Sep. 30, 2011 Predecessor [Member] Distribution [Member]	Sep. 30, 2011 Predecessor [Member] Distribution [Member]	Dec. 31, 2011 Predecessor [Member] Distribution [Member]	Mar. 25, 2012 Predecessor [Member] Total segment [Member]	Sep. 30, 2011 Predecessor [Member] Total segment [Member]	Sep. 30, 2011 Predecessor [Member] Total segment [Member]	Dec. 31, 2011 Predecessor [Member] Total segment [Member]	Mar. 25, 2012 Predecessor [Member] Corporate and other activities [Member]	Sep. 30, 2011 Predecessor [Member] Corporate and other activities [Member]	Sep. 30, 2011 Predecessor [Member] Corporate and other activities [Member]	Dec. 31, 2011 Predecessor [Member] Corporate and other activities [Member]
Segment Reporting Information [Line Items]
Operating revenues from external customers	$ 477,896	$ 990,078	$ 188,481	$ 387,173	$ 213,382	$ 430,215	$ 73,237	$ 167,742	$ 475,100	$ 985,130	$ 2,796	$ 4,948	$ 633,649	$ 617,211	$ 1,995,640		$ 193,921	$ 192,699	$ 584,753		$ 246,463	$ 339,658	$ 891,825		$ 190,499	$ 80,763	$ 506,412		$ 630,883	$ 613,120	$ 1,982,990		$ 2,766	$ 4,091	$ 12,650
Segment Adjusted EBITDA	169,178	274,721	122,486	205,130	25,296	36,155	22,461	35,907			(1,065)	(2,471)	225,753	247,300	723,115		185,706	199,952	570,072		25,338	34,234	94,440		33,554	14,369	58,673						(18,845)	(1,255)	(70)
Depreciation and amortization	(75,710)	(154,909)											(56,544)	(59,327)	(177,949)
Unrealized gains on unhedged derivative activities	0	0											0	5,130	(9,283)
Net gain on curtailment of OPEB plans		15,332											0		0
Non-cash equity-based compensation, accretion expense and amortization of regulatory assets	(7,256)	(12,116)											(1,350)	(2,926)	(7,580)
Other Income (Expense) affecting Segment Adjusted EBITDA	(755)	(564)											284	191	557
Earnings from unconsolidated investments	(1,065)	(381)											16,160	26,686	78,435
Adjusted EBITDA attributable to unconsolidated investments	(3,808)	(7,673)											(61,108)	(79,651)	(194,723)
Interest expense	(34,639)	(96,323)											(50,407)	(54,925)	(165,429)
Income before income tax expense	45,945	18,087											72,788	82,478	247,143
Income tax (benefit) expense	(28,959)	(27,883)											(22,871)	(24,446)	(68,676)
Net income (loss)	16,986	(9,796)											49,917	58,032	178,467
Total assets	$ 9,879,812	$ 9,879,812	$ 5,695,305	$ 5,695,305	$ 2,820,127	$ 2,820,127	$ 1,249,047	$ 1,249,047	$ 9,764,479	$ 9,764,479	$ 115,333	$ 115,333				$ 8,270,859				$ 5,288,967				$ 1,742,516				$ 1,075,253				$ 8,106,736				$ 164,123