CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended	9 Months Ended	3 Months Ended
	Sep. 30, 2013 Successor [Member]	Sep. 30, 2012 Successor [Member]	Sep. 30, 2012 Successor [Member]	Sep. 30, 2013 Successor [Member]	Mar. 25, 2012 Predecessor [Member]
Operating revenues	$ 182	$ 404	$ 822	$ 891	$ 443
Operating expenses:
Cost of natural gas and other energy	1	164	329	226	197
Operating, maintenance and general	73	98	264	281	116
Depreciation and amortization	41	67	137	147	49
Total operating expenses	115	329	730	654	362
Operating income	67	75	92	237	81
Other income (expense):
Interest expense, net of interest capitalized	(39)	(34)	(95)	(84)	(50)
Earnings from unconsolidated investments	9	(1)	0	15	16
Other, net	3	(1)	0	2	(2)
Total other expenses, net	(27)	(36)	(95)	(67)	(36)
Income from continuing operations before income tax expense	40	39	(3)	170	45
Income tax expense (benefit) from continuing operations	(5)	27	21	80	12
Income (Loss) from Continuing Operations	45	12	(24)	90	33
Income from Discontinued Operations	13	5	14	44	17
Net income (loss)	$ 58	$ 17	$ (10)	$ 134	$ 50