Taxes on Income - Components of Income Tax Expense (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2012 Successor [Member]	Mar. 25, 2012 Predecessor [Member]	Dec. 31, 2011 Predecessor [Member]	Dec. 31, 2010 Predecessor [Member]
Current:
Federal	$ (43)	$ 0	$ 2	$ (11)
State	3	(1)	(7)	(3)
Total current	(40)	(1)	(5)	(14)
Deferred:
Federal	81	10	76	82
State	(2)	3	9	12
Total deferred	79	13	85	94
Total federal and state income tax expense (benefit)	$ 39	$ 12	$ 80	$ 80
Effective tax rate	78.00%	27.00%	27.00%	29.00%