Related Party Transactions (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended		12 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended		3 Months Ended				9 Months Ended						3 Months Ended			9 Months Ended		1 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended					9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Energy Future Holdings Corp. [Member]	Sep. 30, 2012 Energy Future Holdings Corp. [Member]	Sep. 30, 2013 Energy Future Holdings Corp. [Member]	Sep. 30, 2012 Energy Future Holdings Corp. [Member]	Dec. 31, 2012 Energy Future Holdings Corp. [Member]	Sep. 30, 2013 Energy Future Holdings Corp. [Member] Texas Competitive Electric Holdings Company LLC [Member]	Sep. 30, 2012 Energy Future Holdings Corp. [Member] Texas Competitive Electric Holdings Company LLC [Member]	Sep. 30, 2013 Energy Future Holdings Corp. [Member] Texas Competitive Electric Holdings Company LLC [Member]	Sep. 30, 2012 Energy Future Holdings Corp. [Member] Texas Competitive Electric Holdings Company LLC [Member]	Sep. 30, 2012 Energy Future Holdings Corp. [Member] Affiliated Entity [Member]	Sep. 30, 2013 Energy Future Holdings Corp. [Member] Affiliated Entity [Member]	Sep. 30, 2012 Energy Future Holdings Corp. [Member] Affiliated Entity [Member]	Sep. 30, 2013 Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member]	Mar. 31, 2013 Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member]	Sep. 30, 2012 Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member]	Mar. 31, 2012 Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member]	Sep. 30, 2013 Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member]	Sep. 30, 2012 Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member]	Dec. 31, 2012 Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member]	Sep. 30, 2013 Texas Competitive Electric Holdings Company LLC [Member] Senior Secured Debt [Member]	Sep. 30, 2013 Texas Competitive Electric Holdings Company LLC [Member] Senior Secured Facilities [Member]	Sep. 30, 2013 Minimum [Member] Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member] Rating-Agencies-Downgrades	Sep. 30, 2013 Debt held by related party [Member] Texas Competitive Electric Holdings Company LLC [Member]	Sep. 30, 2012 Debt held by related party [Member] Texas Competitive Electric Holdings Company LLC [Member]	Mar. 31, 2012 Debt held by related party [Member] Texas Competitive Electric Holdings Company LLC [Member]	Sep. 30, 2013 Debt held by related party [Member] Texas Competitive Electric Holdings Company LLC [Member]	Sep. 30, 2012 Debt held by related party [Member] Texas Competitive Electric Holdings Company LLC [Member]	Aug. 31, 2012 Agreement between parties to settle future reimbursements [Member] Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member] Agreement_settled	Sep. 30, 2012 Agreement between parties to settle obligations under the note [Member] Texas Competitive Electric Holdings Company LLC [Member] Noninterest bearing note payable maturing in 2016 [Member] Oncor [Member]	Sep. 30, 2012 Agreement between parties to settle obligations under the note [Member] Texas Competitive Electric Holdings Company LLC [Member] Noninterest bearing note payable maturing in 2016 [Member] Oncor [Member]	Sep. 30, 2013 Amounts paid relating equipment accounted for as intangible assets [Member] Energy Future Holdings Corp. [Member] Texas Competitive Electric Holdings Company LLC [Member]	Sep. 30, 2013 Decommisioning liablity [Member] Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member]	Dec. 31, 2012 Decommisioning liablity [Member] Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member]	Sep. 30, 2013 Collateral posted [Member] Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member]	Dec. 31, 2012 Collateral posted [Member] Texas Competitive Electric Holdings Company LLC [Member] Oncor [Member]	Sep. 30, 2013 TEXAS State and Local Jurisdiction [Member]	Sep. 30, 2012 TEXAS State and Local Jurisdiction [Member]	Sep. 30, 2013 Audit Years 1997 Through 2002 [Member] State and Local Jurisdiction [Member]	Sep. 30, 2013 Audit Years 1997 Through 2002 [Member] Internal Revenue Service (IRS) [Member]	Sep. 30, 2013 Audit Years 1997 Through 2002 [Member] Internal Revenue Service (IRS) [Member] Energy Future Holdings Corp. [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Interest Income															$ 9	$ 3	$ 33
Average daily balance of notes															683	77	822
Related party transaction, amounts of transaction																		273		281		728	746										159
Due to Affiliate																		158				158		53
Number of agreements related to securitzation (transition) bonds settled																																	2
Long-term debt, gross																									1,571	22,635
Repayments of Related Party Debt																																		0	20	6
Interest expense, related party						1	1	3	2												2		16					10	0	10	29	0
Selling, general and administrative expenses from transactions with related party											59	61	176	178
Delivery fee surcharge remitted to related party																		0	4	5		8	12
Due to Affiliate, Noncurrent																																					352	284
Letter of credit posted as collateral																																							10	11
Event of credit rating downgrade, letter of credit required to be posted to secure payment obligations																		170				170
Event of credit rating downgrade, minimum number of rating agencies downgrade below investment grade (in credit agencies downgrades)																											2
Accrued income taxes payable to parent						7				31																																			84
Affiliate tax sharing liability	723		723		0
Income Tax Expense (Benefit)	$ (17)	$ (228)	$ (476)	$ (692)																																					$ 134	$ 83	$ 14	$ 78