Derivative Instrument and Hedging Activities - Income Stmt (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended		3 Months Ended
	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Mar. 25, 2012
Successor
Derivative [Line Items]
Gain Loss Recognized In Other Comprehensive Income Interest Rate Hedges	$ 0	$ 0	$ 0
Gain Loss Reclassified into Income Interest Rate Hedges	0	0	0
Change in fair value – increase (decrease) in accumulated other comprehensive income	(6)	0	(3)
Reclassification of unrealized gain from accumulated other comprehensive income	1	0	0
Gain Loss Recognized in Interest Expense	12	(7)	29
Gain Loss Recognized In Distribution Commodity Contracts	(32)	0	(7)
Predecessor
Derivative [Line Items]
Gain Loss Recognized In Other Comprehensive Income Interest Rate Hedges				6
Gain Loss Reclassified into Income Interest Rate Hedges				8
Change in fair value – increase (decrease) in accumulated other comprehensive income				5
Reclassification of unrealized gain from accumulated other comprehensive income				2
Gain Loss Recognized in Interest Expense				0
Gain Loss Recognized In Distribution Commodity Contracts				$ (2)