Supplementary Financial Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011
Supplementary Financial Information [Abstract]
Interest expense	$ 116	$ 69	$ 305		$ 194
Interest related to pushed down debt	19	18	57		60
Amortization of debt exchange and issuance costs	2	1	6		5
Total interest expense and related charges	137	88	368		259
Cash payments (receipts) related to:
Interest paid			217		116
Interest received on investments in long-term debt of affiliates			(92)		(83)
Income tax payments			172		30
Noncash investing and financing activities:
Receipt of additional EFH Corp. Toggle Notes in lieu of cash interest			(167)		(151)
Parent's payment of interest on pushed-down debt accounted for as a contribution of capital (net of tax) (Note 6)			30		28
Capital contribution related to settlement of certain income taxes payable			0	[1]	30	[1]
Effect of push down debt from EFH Corp.			$ 0		$ (196)

[1] Reflects noncash settlement of certain income taxes payable arising as a result of the sale of noncontrolling interests in Oncor.