Derivative Instruments (Detail Effect Of Derivative Assets And Liabilities In Statement Of Operations) (Details) (USD $) In Thousands, unless otherwise specified	7 Months Ended	12 Months Ended	7 Months Ended	12 Months Ended	7 Months Ended	12 Months Ended	7 Months Ended	12 Months Ended	7 Months Ended	12 Months Ended	7 Months Ended	12 Months Ended	7 Months Ended	12 Months Ended	7 Months Ended	12 Months Ended	5 Months Ended	12 Months Ended	5 Months Ended	12 Months Ended	5 Months Ended	12 Months Ended	5 Months Ended	12 Months Ended	5 Months Ended	12 Months Ended	5 Months Ended	12 Months Ended	5 Months Ended	12 Months Ended	5 Months Ended	12 Months Ended
	Dec. 31, 2010 Successor [Member] Derivatives In Cash Flow Hedging Relationship [Member]	Dec. 31, 2011 Successor [Member] Derivatives In Cash Flow Hedging Relationship [Member]	Dec. 31, 2010 Successor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Commodity Derivatives [Member] Revenues [Member]	Dec. 31, 2011 Successor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Commodity Derivatives [Member] Revenues [Member]	Dec. 31, 2010 Successor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Interest Rate [Member] Revenues [Member]	Dec. 31, 2011 Successor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Interest Rate [Member] Revenues [Member]	Dec. 31, 2010 Successor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Interest Rate [Member] Interest Expense, Net [Member]	Dec. 31, 2011 Successor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Interest Rate [Member] Interest Expense, Net [Member]	Dec. 31, 2010 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member]	Dec. 31, 2011 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member]	Dec. 31, 2010 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Commodity Derivatives [Member] Revenues [Member]	Dec. 31, 2011 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Commodity Derivatives [Member] Revenues [Member]	Dec. 31, 2010 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Interest Rate [Member] Interest Expense, Net [Member]	Dec. 31, 2011 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Interest Rate [Member] Interest Expense, Net [Member]	Dec. 31, 2010 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Embedded Derivatives [Member] Other Income and Deductions, Net [Member]	Dec. 31, 2011 Successor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Embedded Derivatives [Member] Other Income and Deductions, Net [Member]	May 25, 2010 Predecessor [Member] Derivatives In Cash Flow Hedging Relationship [Member]	Dec. 31, 2009 Predecessor [Member] Derivatives In Cash Flow Hedging Relationship [Member]	May 25, 2010 Predecessor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Commodity Derivatives [Member] Revenues [Member]	Dec. 31, 2009 Predecessor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Commodity Derivatives [Member] Revenues [Member]	May 25, 2010 Predecessor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Interest Rate [Member] Revenues [Member]	Dec. 31, 2009 Predecessor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Interest Rate [Member] Revenues [Member]	May 25, 2010 Predecessor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Interest Rate [Member] Interest Expense, Net [Member]	Dec. 31, 2009 Predecessor [Member] Derivatives In Cash Flow Hedging Relationship [Member] Interest Rate [Member] Interest Expense, Net [Member]	May 25, 2010 Predecessor [Member] Derivatives Not Designated In A Hedging Relationships [Member]	Dec. 31, 2009 Predecessor [Member] Derivatives Not Designated In A Hedging Relationships [Member]	May 25, 2010 Predecessor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Commodity Derivatives [Member] Revenues [Member]	Dec. 31, 2009 Predecessor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Commodity Derivatives [Member] Revenues [Member]	May 25, 2010 Predecessor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Interest Rate [Member] Interest Expense, Net [Member]	Dec. 31, 2009 Predecessor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Interest Rate [Member] Interest Expense, Net [Member]	May 25, 2010 Predecessor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Embedded Derivatives [Member] Other Income and Deductions, Net [Member]	Dec. 31, 2009 Predecessor [Member] Derivatives Not Designated In A Hedging Relationships [Member] Embedded Derivatives [Member] Other Income and Deductions, Net [Member]
Change in value recognized in OCI on derivatives (effective portion)	$ (11,099)	$ (12,678)	$ (11,099)	$ (12,678)	$ 0	$ 0											$ 14,371	$ (22,040)	$ 14,371	$ (19,958)	$ 0	$ (2,082)
Amount of gain (loss) reclassified from AOCI into income (effective portion)	0	(19,018)	0	(19,018)			0	0									(6,260)	48,005	(5,200)	54,260			(1,060)	(6,255)
Amount of gain (loss) recognized in income on ineffective portion			(88)	3															(799)	108
Derivative Instruments, Gain (Loss) Reclassified Amortized from Accumulated OCI into Income, Effective Portion, Net											0	0															4115	-611
Amount of gain (loss) recognized in income on derivatives									$ (19,756)	$ 17,521	$ (7,778)	$ (58)	$ (3,588)	$ (395)	$ (8,390)	$ 17,974									$ (3,695)	$ (29,355)	$ 1,168	$ (13,669)	$ (824)	$ 0	$ (4,039)	$ (15,686)