Benefits - Components of Net Periodic Benefit Cost (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	3 Months Ended				6 Months Ended		9 Months Ended
	Sep. 30, 2012	Mar. 25, 2012 Predecessor		Sep. 30, 2013 Successor	Sep. 30, 2012 Successor	Sep. 30, 2012 Successor		Sep. 30, 2013 Successor
Defined Benefit Plan Disclosure
Service cost		$ 1		$ 0	$ 0	$ 0		$ 0
Interest cost		1		0	0	0		1
Expected return on plan assets		(1)		(2)	(1)	(2)		(4)
Prior service credit amortization		(1)		1	0	0		1
Curtailment recognition	(11)	0	[1]			(11)	[1]	0	[1]
Net periodic benefit cost		0		(1)	(1)	(13)		(2)
Noncurrent refund liability	$ 59

[1] Subsequent to the ETE Merger, the Company amended certain of its OPEB plans to prospectively restrict participation in the plans for certain active employees. The plan amendments resulted in the plans becoming currently over-funded and, accordingly, the Company recorded a gross pre-tax curtailment gain of $70 million, $59 million of which is subject to refund to customers; thus, the net curtailment gain recognition was $11 million.