Related-Party Transactions (Energy Future Competitive Holdings CO Related Party Information) (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
Related Party Transaction [Line Items]
Contractual Interest on Debt Classified as LSTC	$ 522	$ 516	$ 874	$ 1,554
Energy Future Holdings Corp. [Member]
Related Party Transaction [Line Items]
Intercompany payables	107			107		$ 107
Interest expense, related party					$ 2
Texas Competitive Electric Holdings Company LLC
Related Party Transaction [Line Items]
Contractual Interest on Debt Classified as LSTC	520	514	$ 871	1,549
Texas Competitive Electric Holdings Company LLC | Debt held by related party [Member]
Related Party Transaction [Line Items]
Intercompany payables						382
Interest expense, related party		0		1	13
Contractual Interest on Debt Classified as LSTC		$ 9		28	$ 16
Texas Competitive Electric Holdings Company LLC | Energy Future Holdings Corp. [Member] | Senior Notes [Member] | Debt held by related party [Member]
Related Party Transaction [Line Items]
Intercompany payables	284			284		284
Texas Competitive Electric Holdings Company LLC | Energy Future Holdings Corp. [Member] | Term loan Facilities [Member] | Debt held by related party [Member]
Related Party Transaction [Line Items]
Intercompany payables	19			19		19
Texas Competitive Electric Holdings Company LLC | Energy Future Intermediate Holding CO LLC [Member] | Senior Notes [Member] | Debt held by related party [Member]
Related Party Transaction [Line Items]
Intercompany payables	$ 79			$ 79		$ 79