Pension And Other Postretirement Employee Benefits (OPEB) Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	$ 3	$ 10	$ 9	$ 31
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Assumptions used calculating net periodic benefit cost, discount rate			4.30%
Assumptions used calculating net periodic benefit cost, expected long-term return on assets			5.40%
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Assumptions used calculating net periodic benefit cost, discount rate			4.10%
Assumptions used calculating net periodic benefit cost, expected long-term return on assets			6.70%
Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year			2
Oncor Plan [Member] | Texas Competitive Electric Holdings Company LLC [Member] | Termination Plan Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Settlement Costs Allocated To Subsidiary Expected to Settle Next Year			$ 50