Reportable Segments 1 (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	3 Months Ended														0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended	0 Months Ended	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 Transportation and Storage [Member]	Dec. 31, 2012 Transportation and Storage [Member]	Mar. 31, 2013 Gathering and Processing [Member]	Dec. 31, 2012 Gathering and Processing [Member]	Mar. 31, 2013 Distribution [Member]		Dec. 31, 2012 Distribution [Member]		Mar. 31, 2013 Corporate and other activities [Member]	Dec. 31, 2012 Corporate and other activities [Member]	Mar. 31, 2013 Total segment [Member]	Dec. 31, 2012 Total segment [Member]	Mar. 31, 2012 Successor [Member]	Mar. 31, 2013 Successor [Member]	Mar. 31, 2012 Successor [Member] Transportation and Storage [Member]	Mar. 31, 2013 Successor [Member] Transportation and Storage [Member]	Mar. 31, 2012 Successor [Member] Gathering and Processing [Member]	Mar. 31, 2013 Successor [Member] Gathering and Processing [Member]	Mar. 31, 2012 Successor [Member] Distribution [Member]	Mar. 31, 2013 Successor [Member] Distribution [Member]	Mar. 31, 2012 Successor [Member] Corporate and other activities [Member]	Mar. 31, 2013 Successor [Member] Corporate and other activities [Member]	Mar. 31, 2012 Successor [Member] Total segment [Member]	Mar. 31, 2013 Successor [Member] Total segment [Member]	Mar. 25, 2012 Predecessor [Member]	Mar. 25, 2012 Predecessor [Member] Transportation and Storage [Member]	Mar. 25, 2012 Predecessor [Member] Gathering and Processing [Member]	Mar. 25, 2012 Predecessor [Member] Distribution [Member]	Mar. 25, 2012 Predecessor [Member] Corporate and other activities [Member]	Mar. 25, 2012 Predecessor [Member] Total segment [Member]
Segment Reporting Information [Line Items]
Operating revenues from external customers																$ 31	$ 393	$ 13	$ 199	$ 20	$ 190			$ (2)	$ 4	$ 33	$ 389	$ 443	$ 194	$ 246		$ 3	$ 440
Segment Adjusted EBITDA																(56)	161	(33)	124	(11)	(6)	(10)	39	(2)	4			226	186	25	34	(19)
Depreciation and amortization																(4)	(59)	(3)	(42)	(1)	(17)			0	0	(4)	(59)	(49)	(30)	(18)		(1)	(48)
Net gain on curtailment of OPEB plans	15															15	0											0
Non-cash equity-based compensation, accretion expense and amortization of regulatory assets																0	(2)											(1)
Other, net																0	1											(2)
Earnings from unconsolidated investments		1														0	1	0	0	0	0			0	1			16	16	0		0
Adjusted EBITDA attributable to unconsolidated investments																0	(5)											(61)
Adjusted EBITDA attributable to discontinued operations																(3)	(40)											(34)
Interest expense																(4)	(33)											(50)
Income from continuing operations before income tax expense																(52)	24											45
Total assets		$ 10,146	$ 9,993	$ 6,198	$ 6,219	$ 2,038	$ 1,965	$ 1,224	[1]	$ 1,190	[1]	$ 686	$ 619	$ 9,460	$ 9,374

[1] (1)Distribution segment assets have been reported as assets held for sale in the consolidated balance sheets at March 31, 2013 and December 31, 2012.