Membership Interests (Principal Amounts, Coupon Rates, Maturities and Carrying Value) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
EFH Corp. 5.55% Fixed Senior Notes Series P due November 15, 2014 [Member]
Stockholders' Equity [Line Items]
Available-for-Sale Securities, Debt Securities, Principal Amount Outstanding	$ 281	$ 281
Available-for-sale Securities, Fair Value Disclosure	185	185
EFH Corp. 6.50% Fixed Senior Notes Series Q due November 15, 2024 [Member]
Stockholders' Equity [Line Items]
Available-for-Sale Securities, Debt Securities, Principal Amount Outstanding	545	545
Available-for-sale Securities, Fair Value Disclosure	249	249
EFH Corp. 6.55% Fixed Senior Notes Series R due November 15, 2034 [Member]
Stockholders' Equity [Line Items]
Available-for-Sale Securities, Debt Securities, Principal Amount Outstanding	456	456
Available-for-sale Securities, Fair Value Disclosure	194	194
Fixed 10.25% Senior Notes due November 1, 2015 [Member]
Stockholders' Equity [Line Items]
Available-for-Sale Securities, Debt Securities, Principal Amount Outstanding	79	79
Available-for-sale Securities, Fair Value Disclosure	7	7
Debt Securities [Member]
Stockholders' Equity [Line Items]
Available-for-Sale Securities, Debt Securities, Principal Amount Outstanding	1,361	1,361
Available-for-sale Securities, Fair Value Disclosure	635	635
Senior Notes [Member] | EFH Corp. 5.55% Fixed Senior Notes Series P due November 15, 2014 [Member]
Stockholders' Equity [Line Items]
Stated interest rate (as a percent)	5.55%
Senior Notes [Member] | EFH Corp. 6.50% Fixed Senior Notes Series Q due November 15, 2024 [Member]
Stockholders' Equity [Line Items]
Stated interest rate (as a percent)	6.50%
Senior Notes [Member] | EFH Corp. 6.55% Fixed Senior Notes Series R due November 15, 2034 [Member]
Stockholders' Equity [Line Items]
Stated interest rate (as a percent)	6.55%
Senior Notes [Member] | Fixed 10.25% Senior Notes due November 1, 2015, Series B [Member]
Stockholders' Equity [Line Items]
Stated interest rate (as a percent)	10.25%
TCEH Corp. [Member] | Series B [Member]
Stockholders' Equity [Line Items]
Notes Payable, Current	$ 48	$ 48