Equity (Equity) (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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			$ (10,394)		$ (7,716)
Net loss			(686)		(1,298)
Gain on settlement of reimbursement agreement with Oncor (Note 11)					2
Effect of stock-based incentive compensation plans					6
Net effect of cash flow hedges	1	1	5		5
Investment by noncontrolling interests			3		6
Effect of debt push-down from EFH Corp. (a)			437	[1]	30	[1]
Other					0
Ending Balance	(10,643)	(8,965)	(10,643)		(8,965)
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			7,665		7,351
Net loss			0		0
Gain on settlement of reimbursement agreement with Oncor (Note 11)					2
Effect of stock-based incentive compensation plans					6
Net effect of cash flow hedges			0		0
Investment by noncontrolling interests			0		0
Effect of debt push-down from EFH Corp. (a)			434	[1]	30	[1]
Other					(1)
Ending Balance	0	7,388	0		7,388
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			(18,129)		(15,121)
Net loss			(526)		(1,298)
Gain on settlement of reimbursement agreement with Oncor (Note 11)					0
Effect of stock-based incentive compensation plans					0
Net effect of cash flow hedges			0		0
Investment by noncontrolling interests			0		0
Effect of debt push-down from EFH Corp. (a)			0		0
Other					0
Ending Balance	0	(16,419)	0		(16,419)
Membership Interests [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			0
Net loss			(160)
Net effect of cash flow hedges			0
Investment by noncontrolling interests			0
Effect of debt push-down from EFH Corp. (a)			3
Ending Balance	(10,711)		(10,711)
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			(42)		(49)
Net loss			0		0
Gain on settlement of reimbursement agreement with Oncor (Note 11)					0
Effect of stock-based incentive compensation plans					0
Net effect of cash flow hedges			5		5
Investment by noncontrolling interests			0		0
Effect of debt push-down from EFH Corp. (a)			0		0
Other					0
Ending Balance	(37)	(44)	(37)		(44)
Noncontrolling Interest [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			112		103
Net loss			0		0
Gain on settlement of reimbursement agreement with Oncor (Note 11)					0
Effect of stock-based incentive compensation plans					0
Net effect of cash flow hedges			0		0
Investment by noncontrolling interests			3		6
Effect of debt push-down from EFH Corp. (a)			0		0
Other					1
Ending Balance	$ 105	$ 110	$ 105		$ 110

[1] Represents the interest and income tax effects of debt pushed down from EFH Corp. (Note 5).