Interest Expense and Related Charges (Interest Expense and Related Charges) (Details) - USD ($) $ in Millions		3 Months Ended		5 Months Ended	9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Interest Expense and Related Charges [Line Items]
Interest paid/accrued on debtor-in-possession financing		$ 16	$ 16		$ 47	$ 22
Adequate protection amounts paid/accrued (a)	[1]	311	308		920	519
Interest paid/accrued on pre-petition debt (b)	[2]	1	3		7	883
Interest related to pushed down debt		0	0		0	1
Noncash realized loss on termination of interest rate swaps (Note 6)	[3]	0	0		0	1,225
Unrealized mark-to-market net gain on interest rate swaps		0	0		0	(1,290)
Amortization of debt issuance, amendment and extension costs and discounts		0	1		0	86
Capitalized interest		(2)	(3)		(8)	(14)
Total interest expense and related charges		326	325		967	1,434
Liabilities Subject To Compromise, Debt		31,192			31,192		$ 31,192
Liabilities Subject To Compromise, Liability Under Terminated Agreements, Net		1,235			1,235		1,235
Adequate Protection Interest Paid-Accrued, Amount Excluded Related To Terminated Natural Gas Hedging Positions And Interest Rate Swaps		15	15	$ 25	44
Contractual Interest on Debt Classified as LSTC		522	516	874	1,554
Adequate Protection Paid/Accrued		296	293	494	876
Contractual Interest on Debt Classified as LSTC Not Paid/Accrued		226	223	380	678
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion		0	0		0	(1)
Amortization of fair value debt discounts resulting from purchase accounting		0	0		1	3
Energy Future Competitive Holdings Company [Member]
Interest Expense and Related Charges [Line Items]
Contractual Interest on Debt Classified as LSTC		2	2	3	5
Adequate Protection Paid/Accrued		0	0	0	0
Contractual Interest on Debt Classified as LSTC Not Paid/Accrued		2	2	3	5
Texas Competitive Electric Holdings Company LLC
Interest Expense and Related Charges [Line Items]
Liabilities Subject To Compromise, Debt		31,856			31,856		31,856
Contractual Interest on Debt Classified as LSTC		520	514	871	1,549
Adequate Protection Paid/Accrued		296	293	494	876
Contractual Interest on Debt Classified as LSTC Not Paid/Accrued		224	$ 221	$ 377	673
Interest rate swaps [Member] | Texas Competitive Electric Holdings Company LLC
Interest Expense and Related Charges [Line Items]
Noncash realized loss on termination of interest rate swaps (Note 6)						1,225
Gain (Loss) on Derivative Instruments, Net, Pretax						193
Gain (Loss) On Derivative Instruments, Net, Pretax, Representing Matured Positions Not Settled In Cash During the Period						$ 127
Line of Credit [Member] | Texas Competitive Electric Holdings Company LLC
Interest Expense and Related Charges [Line Items]
Liabilities Subject To Compromise, Debt		22,635			22,635
Secured Debt [Member] | Texas Competitive Electric Holdings Company LLC
Interest Expense and Related Charges [Line Items]
Liabilities Subject To Compromise, Debt		1,571			1,571
11.5% Fixed Senior Secured Notes due October 1, 2020 [Member] | Secured Debt [Member] | Texas Competitive Electric Holdings Company LLC
Interest Expense and Related Charges [Line Items]
Liabilities Subject To Compromise, Debt		$ 1,750			$ 1,750		$ 1,750
Adequate Protection Interest Expense [Member]
Interest Expense and Related Charges [Line Items]
Adequate Protection Paid Or Accrued, Weighted Average Interest Rate		4.68%			4.68%
Adequate Protection Paid Or Accrued, Basis Spread on Variable Rate					4.50%

[1] Post-petition period only.

[2] Includes amounts related to interest rate swaps totaling $193 million for the nine months ended September 30, 2014. Of the $193 million for the nine months ended September 30, 2014, $127 million is included in the liability arising from the termination of TCEH interest rate swaps discussed in Note 13.

[3] See Note 13.