Chapter 11 Cases (Details)	1 Months Ended	3 Months Ended		5 Months Ended	9 Months Ended
	Apr. 30, 2015	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Nov. 03, 2015	Sep. 22, 2015 USD ($)
Schedule of Reorganization Costs [Line Items]
Goodwill, Period Increase (Decrease)		$ 700,000,000				$ 0
Proposed Plan Of Reorganization, Maximum Reimbursement Of Fees And Expenses In Event Of Termination Of Merger And Purchase Agreement, Backstop Agreement Or Equity Commitment Letter								$ 35,000,000
Debtor Reorganization Items, Net Gain (Loss) on Rejection of Leases and Other Executory Contracts		$ 0	$ 0	$ 0	$ (28,000,000)	$ 0
Texas Competitive Electric Holdings Company LLC | Secured Debt [Member]
Schedule of Reorganization Costs [Line Items]
Reorganization Plan, Common Stock of Reorganized Entity Debtholders To Receive	1260000000000.00%
Investor Group [Member]
Schedule of Reorganization Costs [Line Items]
Proposed Plan Of Reorganization, Merger And Purchase Agreement, Equity Commitment Letter								2,013,000,000
Subsequent Event [Member]
Schedule of Reorganization Costs [Line Items]
ERROR in label resolution.							13,900
Bankruptcy Claims, Number Of Claims Settled, Withdrawn or Expunged By Bankruptcy Court							5,000
Senior Secured Term Loan Facility [Member] | Investor Group [Member] | Debt Commitment Letter [Member]
Schedule of Reorganization Costs [Line Items]
Proposed Plan Of Reorganization, Merger And Purchase Agreement, Debt Commitment Letter								5,500,000,000
Senior Secured Bridge Loan Facility [Member] | Investor Group [Member] | Debt Commitment Letter [Member]
Schedule of Reorganization Costs [Line Items]
Proposed Plan Of Reorganization, Merger And Purchase Agreement, Debt Commitment Letter								300,000,000
Holders Of Unsecured Debt Claims, Second Lien Debt Claims And General Unsecured Claims [Member] | Ovation Acquisition I, LLC [Member]
Schedule of Reorganization Costs [Line Items]
Proposed Plan Of Reorganization, Rights Offering, Offering Of Equity Rights In Common Stock								5,087,000,000
Holders Of First Lien Secured Claims Against TCEH [Member] | Ovation Acquisition I, LLC [Member]
Schedule of Reorganization Costs [Line Items]
Proposed Plan Of Reorganization, Rights Offering, Offering Of Equity Rights In Common Stock								700,000,000
Rights Offering Participants [Member] | Ovation Acquisition I, LLC [Member]
Schedule of Reorganization Costs [Line Items]
Proposed Plan Of Reorganization, Rights Offering, Offering Of Equity Rights In Common Stock								5,787,000,000
Rights Offering Participants [Member] | Backstop Purchasers [Member]
Schedule of Reorganization Costs [Line Items]
Rights Offering, Backstop Agreement								$ 5,087,000,000