CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended	3 Months Ended
	Jun. 30, 2013 Successor [Member]	Jun. 30, 2012 Successor [Member]	Jun. 30, 2012 Successor [Member]	Jun. 30, 2013 Successor [Member]	Mar. 25, 2012 Predecessor [Member]
Operating revenues	$ 316	$ 387	$ 418	$ 709	$ 443
Operating expenses:
Cost of natural gas and other energy	66	151	165	225	197
Operating, maintenance and general	88	105	166	208	116
Depreciation and amortization	47	66	70	106	49
Total operating expenses	201	322	401	539	362
Operating income	115	65	17	170	81
Other income (expense):
Interest expense, net of interest capitalized	(12)	(57)	(61)	(45)	(50)
Earnings from unconsolidated investments	5	1	1	6	16
Other, net	(2)	1	1	(1)	(2)
Total other expenses, net	(9)	(55)	(59)	(40)	(36)
Income from continuing operations before income tax expense	106	10	(42)	130	45
Income tax expense (benefit) from continuing operations	75	6	(6)	85	12
Income (Loss) from Continuing Operations	31	4	(36)	45	33
Income from Discontinued Operations	9	8	9	31	17
Net income (loss)	$ 40	$ 12	$ (27)	$ 76	$ 50