Related-Party Transactions (Cash Payments Made To (Received From) Members In Lieu Of Income Taxes) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Related Party Transaction [Line Items]
Federal income taxes		$ 144
Texas margin taxes	$ 22	20
Total payments (receipts)	22	164
EFH Corp [Member]
Related Party Transaction [Line Items]
Federal income taxes		115
Texas margin taxes	22	20
Total payments (receipts)	$ 22	135
Texas Transmission and Investment LLC [Member]
Related Party Transaction [Line Items]
Federal income taxes		29
Total payments (receipts)		$ 29