Related-Party Transactions (Narrative) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended	1 Months Ended				12 Months Ended
	Aug. 31, 2012 Agreement_settled	Dec. 31, 2013	Jul. 31, 2014	Jan. 31, 2013	Feb. 29, 2012	Oct. 31, 2012	Dec. 31, 2014	Dec. 31, 2012	Mar. 31, 2014
Related Party Transaction [Line Items]
Deferred Tax Assets, Valuation Allowance		$ 110us-gaap_IncomeTaxesReceivable					$ 125us-gaap_IncomeTaxesReceivable
Long Term Debt And Capital Leases Issued, Principal Amount		1,564
Number of Agreements Related to Securitization (Transition) Bonds Settled	2
Oncor [Member]
Related Party Transaction [Line Items]
Equity Method Investment, Ownership Percentage							80.00%
Secured Debt [Member] \| 9.75% Fixed Senior Secured First Lien Notes due October 15, 2019 [Member]
Related Party Transaction [Line Items]
Stated interest rate (as a percent)							9.75%
Secured Debt [Member] \| 11.75% Senior Secured Second Lien Notes due March 1, 2022 [Member]
Related Party Transaction [Line Items]
Stated interest rate (as a percent)							11.75%
Secured Debt [Member] \| 6.875% Fixed Senior Secured First Lien Notes due August 15, 2017 [Member]
Related Party Transaction [Line Items]
Stated interest rate (as a percent)							6.875%
Push Down Debt [Member] \| 9.75% Fixed Senior Secured First Lien Notes due October 15, 2019 [Member]
Related Party Transaction [Line Items]
Stated interest rate (as a percent)							9.75%
Push Down Debt [Member] \| 10% EFH Corp. Fixed Senior Secured Notes due January 15, 2020 [Member]
Related Party Transaction [Line Items]
Effective interest rate (as a percent)							10.00%
Push Down Debt [Member] \| 10.875% EFH Corp. Fixed Senior Notes due November 1, 2017 [Member]
Related Party Transaction [Line Items]
Stated interest rate (as a percent)							10.875%
Energy Future Holdings Corp. [Member] \| Other Postretirement Benefit Plan [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Reimbursement Due to Parent			1
Energy Future Holdings Corp. [Member] \| Receivable attributable to income taxes [Member]
Related Party Transaction [Line Items]
Due from Affiliate, Current		18
Energy Future Holdings Corp. [Member] \| Payable Attributable To Income Taxes [Member] \| State and Local Jurisdiction [Member]
Related Party Transaction [Line Items]
Due to Affiliate, Current		23					24
Goldman, Sachs & Co. [Member]
Related Party Transaction [Line Items]
Debt Issuance Cost				2
Goldman, Sachs & Co. [Member] \| Secured Debt [Member] \| 11.75% Senior Secured Second Lien Notes due March 1, 2022 [Member]
Related Party Transaction [Line Items]
Debt Issuance Cost	3				7
Affiliates of KKR and TPG Management, L.P. [Member] \| Secured Debt [Member] \| 11.75% Senior Secured Second Lien Notes due March 1, 2022 [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction						4
Oncor [Member]
Related Party Transaction [Line Items]
Related Party Tax Expense, Due to Affiliates, Current		90					237	3
Oncor [Member] \| Internal Revenue Service (IRS) [Member] \| Audit Years 1997 Through 2002 [Member]
Related Party Transaction [Line Items]
Related Party Tax Expense, Due from Affiliates, Current							33
Oncor Holdings [Member]
Related Party Transaction [Line Items]
Related Party Tax Expense, Due to Affiliates, Current		34					24	35
Oncor Holdings [Member] \| Federal Tax Refund [Member]
Related Party Transaction [Line Items]
Related Party Tax Expense, Due to Affiliates, Current								21
Oncor [Member] \| Texas Competitive Electric Holdings Company LLC [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction		967					971	962
Due from Affiliates		135					118
Related Party, Remaining Interest To Be Paid	53
Interest Expense, Related Party								16
Public Utilities, Delivery Fee Surcharge Remitted To Related Party		16					17	16
Related Party, Event of Credit Rating Downgrade, Letter of Credit Required to be Posted to Secure Payment Obligations							170
Related Party, Event of Credit Rating Downgrade, Minimum Number of Rating Agencies Downgrade Below Investment Grade							2
Oncor [Member] \| Texas Competitive Electric Holdings Company LLC [Member] \| Related Party Transactions, Agreement Between Parties to Settle Obligations Under The Note [Member] \| Noninterest bearing note payable maturing in 2016 [Member]
Related Party Transaction [Line Items]
Repayments of Related Party Debt								20
Oncor [Member] \| Texas Competitive Electric Holdings Company LLC [Member] \| Collateral posted [Member]
Related Party Transaction [Line Items]
Related Party, Letter of Credit Posted as Collateral		9					9
Oncor [Member] \| Energy Future Holdings Corp. [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party		32					34	35
Oncor [Member] \| Energy Future Holdings Corp. [Member] \| Texas Comptroller Of Public Accounts [Member] \| Audit Years 1997 Through 2001 [Member]
Related Party Transaction [Line Items]
Related Party Tax Expense, Due to Affiliates, Current							10
Oncor [Member] \| Energy Future Holdings Corp. [Member] \| Receivable attributable to income taxes [Member]
Related Party Transaction [Line Items]
Due from Affiliate, Current							144
Due from Affiliate, Noncurrent							64
Oncor [Member] \| Energy Future Holdings Corp. [Member] \| Payable Attributable To Income Taxes [Member]
Related Party Transaction [Line Items]
Due to Affiliate, Current		5
Energy Future Intermediate Holding CO LLC [Member] \| Secured Debt [Member] \| 6.875% Fixed Senior Secured First Lien Notes due August 15, 2017 [Member]
Related Party Transaction [Line Items]
Long Term Debt And Capital Leases Issued, Principal Amount						253
Energy Future Intermediate Holding CO LLC [Member] \| Energy Future Holdings Corp. [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party		0					4	0
Energy Future Intermediate Holding CO LLC [Member] \| Energy Future Holdings Corp. [Member] \| Sponsor Fees Allocated [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Selling, General and Administrative Expenses From Transactions With Related Party, Allocated To Subsidiary		0					3	0
Energy Future Intermediate Holding CO LLC [Member] \| Energy Future Holdings Corp. [Member] \| Legal And Consulting Fees [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Selling, General and Administrative Expenses From Transactions With Related Party, Allocated To Subsidiary		12					4	0
Energy Future Intermediate Holding CO LLC [Member] \| Oncor [Member] \| Related Party Transactions, Agreement Between Parties To Settle Future Reimbursements [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Decrease in Member Interest, After Tax								2
Related Party Transaction, Decrease in Investment in Unconsolidated Subsidiary, Offsetting Decrease in Equity								1
Energy Future Intermediate Holding CO LLC [Member]
Related Party Transaction [Line Items]
Equity Method Investment, Ownership Percentage							80.03%
Energy Future Intermediate Holding CO LLC [Member] \| Texas Competitive Electric Holdings Company LLC [Member] \| Related Party Transactions, Agreement Between Parties To Settle Future Reimbursements [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Amounts of Transaction	159
Energy Future Intermediate Holding CO LLC [Member] \| Energy Future Holdings Corp. [Member] \| Income tax payments [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party							0	180
Related Party Tax Expense, Due from Affiliates, Current		5
Energy Future Intermediate Holding CO LLC [Member] \| TCEH to EFH [Member] \| Indirect Guarantee of Indebtedness [Member] \| Line of Credit [Member]
Related Party Transaction [Line Items]
Long-term debt, gross								698
Energy Future Intermediate Holding CO LLC [Member] \| Goldman, Sachs & Co. [Member] \| Secured Debt [Member] \| Senior 11 Point 750 Percent Secured Second Lien Notes and 6 Point 875 Percent Senior Secured Notes [Member]
Related Party Transaction [Line Items]
Debt Issuance Cost								10
Energy Future Intermediate Holding CO LLC [Member] \| Goldman, Sachs & Co. [Member] \| Secured Debt [Member] \| 11.75% Senior Secured Second Lien Notes due March 1, 2022 [Member]
Related Party Transaction [Line Items]
Debt Instrument, Face Amount	600				1,150
Energy Future Intermediate Holding CO LLC [Member] \| Goldman, Sachs & Co. [Member] \| Secured Debt [Member] \| 6.875% Fixed Senior Secured First Lien Notes due August 15, 2017 [Member]
Related Party Transaction [Line Items]
Debt Instrument, Face Amount	250
Related Party Transaction, Amounts of Transaction						1
Energy Future Intermediate Holding CO LLC [Member] \| Oncor [Member] \| Related Party Transactions, Agreement Between Parties To Settle Future Reimbursements [Member]
Related Party Transaction [Line Items]
Equity Method Investment, Ownership Percentage		80.00%
Oncor Holdings [Member] \| Oncor [Member]
Related Party Transaction [Line Items]
Percentage Of Equity Method Investment Consolidated Revenues Related To Services Provided To Entity		27.00%					25.00%	29.00%
Oncor Holdings [Member] \| Energy Future Holdings Corp. [Member] \| Receivable attributable to income taxes [Member]
Related Party Transaction [Line Items]
Due from Affiliate, Current							120
Oncor Holdings [Member] \| Energy Future Holdings Corp. [Member] \| Payable Attributable To Income Taxes [Member]
Related Party Transaction [Line Items]
Due to Affiliate, Current							7
Oncor Holdings [Member] \| TCEH to EFH [Member]
Related Party Transaction [Line Items]
Multiemployer Plans, Collective-Bargaining Arrangement, Liability of Nonrecoverable Portion of Unfunded Obligation									$ 20

Energy Future Intermediate Holding CO LLC 10-K