Asset Retirement Obligations (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended					12 Months Ended	9 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008	Dec. 31, 2012	Dec. 31, 2010 offshore [Member]	Dec. 31, 2012 Successor [Member]	Mar. 25, 2012 Successor [Member]	Mar. 25, 2012 Predecessor [Member]	Dec. 31, 2011 Predecessor [Member]	Dec. 31, 2010 Predecessor [Member]	Dec. 31, 2009 Predecessor [Member]
ARO Assets Table Text Block [Line Items]
ARO Underlying Asset					$ 5
Asset Retirement Obligation							46	46	46	46	62	62
Asset Retirement Obligation, Liabilities Incurred			8	34		29	0		0	1	30
Asset Retirement Obligation, Revision of Estimate						11	3		0	0	(11)
Asset Retirement Obligation, Liabilities Settled	17	20					5		0	17	20
Asset Retirement Obligation, Accretion Expense							$ (2)		$ 0	$ 0	$ (1)