Oncor Electric Delivery 10-K 9 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Mar. 09, 2017
Entity Registrant Name	ONCOR ELECTRIC DELIVERY CO LLC
Entity Central Index Key	1,193,311
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		0
Entity Current Reporting Status	No
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	Yes
Entity Public Float	$ 0
Oncor's Management and Board of Directors [Member]
Entity Outstanding Membership Interests		0.22%
Oncor Electric Delivery Holdings Company LLC [Member]
Entity Outstanding Membership Interests		80.03%
Texas Transmission Investment LLC [Member]
Entity Outstanding Membership Interests		19.75%

Statements of Consolidated Inco

Statements of Consolidated Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating revenues:
Nonaffiliates	$ 3,205	$ 2,923	$ 2,851
Affiliates	715	955	971
Total operating revenues	3,920	3,878	3,822
Operating expenses:
Wholesale transmission service	894	802	755
Operation and maintenance (Note 12)	754	724	698
Depreciation and amortization	785	863	851
Provision in lieu of income taxes (Notes 1, 4 and 12)	259	260	280
Taxes other than amounts related to income taxes	451	450	438
Total operating expenses	3,143	3,099	3,022
Operating income	777	779	800
Other income and deductions:
Other income and (deductions) - net (Note 13)	(15)	(22)	1
Nonoperating provision in lieu of income taxes (Note 4)	(5)	(8)	(2)
Interest expense and related charges (Note 13)	336	333	353
Net income	$ 431	$ 432	$ 450

Statements of Consolidated Comp

Statements of Consolidated Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statements Of Consolidated Comprehensive Income [Abstract]
Net income	$ 431	$ 432	$ 450
Other comprehensive income (loss):
Cash flow hedges – derivative value net loss recognized in net income (net of tax expense of $1, $1 and $1) (Note 1)	2	2	2
Defined benefit pension plans (net of tax benefit of $-, $4 and $33) (Note 10)		(8)	(61)
Total other comprehensive income (loss)	2	(6)	(59)
Comprehensive income	$ 433	$ 426	$ 391

Statements Of Consolidated Com4

Statements Of Consolidated Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statements Of Consolidated Comprehensive Income [Abstract]
Cash flow hedges - derivative value net loss recognized in net income, tax expense	$ 1	$ 1	$ 1
Defined benefit pension plans- net tax benefit		$ 4	$ 33

Statements Of Consolidated Cash

Statements Of Consolidated Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows - operating activities:
Net income	$ 431	$ 432	$ 450
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	833	908	892
Provision in lieu of deferred income taxes - net	181	40	148
Other - net	(4)	(4)	(3)
Changes in operating assets and liabilities:
Accounts receivable - trade (including affiliates)	(34)	12	8
Inventories	(7)	(8)	(9)
Accounts payable - trade (including affiliates)	14	(21)	15
Regulatory accounts related to reconcilable tariffs (Note 5)	(55)	11	(44)
Other - assets	37	22	(233)
Other - liabilities	33	(31)	52
Cash provided by operating activities	1,429	1,361	1,276
Cash flows - financing activities:
Issuances of long-term debt (Note 7)	175	725	250
Repayments of long-term debt (Note 7)	(41)	(639)	(131)
Net (decrease) increase in short-term borrowings (Note 6)	(51)	129	(34)
Distributions to members (Note 9)	(230)	(436)	(282)
Debt discount, premium, financing and reacquisition costs - net	10	(12)	(5)
Cash used in financing activities	(137)	(233)	(202)
Cash flows - investing activities:
Capital expenditures (Note 12)	(1,352)	(1,154)	(1,107)
Other - net	51	47	10
Cash used in investing activities	(1,301)	(1,107)	(1,097)
Net change in cash and cash equivalents	(9)	21	(23)
Cash and cash equivalents - beginning balance	25	4	27
Cash and cash equivalents - ending balance	$ 16	$ 25	$ 4

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents		$ 16	$ 25
Restricted cash - Bondco (Note 13)		0	38
Trade accounts receivable from nonaffiliates - net (Note 13)		545	388
Trade accounts and other receivables from affiliates - net (Note 12)			118
Amounts receivable from members related to income taxes (Note 12)		80	136
Materials and supplies inventories - at average cost		89	82
Prepayments and other current assets		100	89
Total current assets		830	876
Investments and other property (Note 13)		100	97
Property, plant and equipment - net (Note 13)		13,829	13,024
Goodwill (Notes 1 and 13)		4,064	4,064
Regulatory assets - net (Note 5)		1,974	1,958
Other noncurrent assets		14	32
Total assets		20,811	19,287
Current liabilities:
Short-term borrowings (Note 6)		789	840
Long-term debt due currently (Note 7)	[1]	324
Trade accounts payable (Note 12)		231	150
Amounts payable to members related to income taxes (Note 12)		20	20
Accrued taxes other than amounts related to income		182	181
Accrued interest		83	82
Other current liabilities		144	144
Total current liabilities		1,773	1,458
Long-term debt, less amounts due currently (Note 7)	[1]	5,515	5,646
Liability in lieu of deferred income taxes (Notes 1, 4 and 12)		2,788	2,612
Regulatory liabilities (Note 5)		856	764
Employee benefit obligations and other (Notes 12 and 13)		2,168	2,063
Total liabilities		13,100	11,779
Commitments and contingencies (Note 8)
Membership interests (Note 9):
Capital account — number of interests outstanding 2016 and 2015 - 635,000,000		7,822	7,621
Accumulated other comprehensive loss		(111)	(113)
Total membership interests		7,711	7,508
Total liabilities and membership interests		20,811	19,287
Oncor [Member]
Current assets:
Regulatory assets - net (Note 5)			1,184
Bondco [Member]
Current assets:
Regulatory assets - net (Note 5)			10
Current liabilities:
Long-term debt due currently (Note 7)	[2]		$ 41
Regulatory liabilities (Note 5)		$ 0
[1]	Secured by first priority lien on certain transmission and distribution assets equally and ratably with all of Oncor's other secured indebtedness. See "Deed of Trust" below for additional information.
[2]	The transition bonds were nonrecourse to Oncor and were issued to securitize a regulatory asset.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - shares	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Consolidated Balance Sheets [Abstract]
Capital account, interests outstanding	635,000,000	635,000,000	635,000,000

Statements Of Consolidated Memb

Statements Of Consolidated Membership Interests - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Capital account:
Balance at beginning of period		$ 7,621		$ 7,625	$ 7,621	$ 7,625	$ 7,457
Net income	$ 77	81	$ 73	98	431	432	450
Distributions to members					(230)	(436)	(282)
Balance at end of period (number of interests outstanding: 2016, 2015 and 2014 – 635 million)	7,822		7,621		7,822	7,621	7,625
Accumulated other comprehensive income (loss) net of tax effects:
Balance at beginning of period		$ (113)		$ (107)	(113)	(107)	(48)
Net effects of cash flow hedges (net of tax expense of $1, $1 and $1)					2	2	2
Defined benefit pension plans (net of tax benefit of $-, $4 and $33) (Note 10)						(8)	(61)
Balance at end of period	(111)		(113)		(111)	(113)	(107)
Total membership interests at end of period	$ 7,711		$ 7,508		$ 7,711	$ 7,508	$ 7,518

Statements Of Consolidated Mem9

Statements Of Consolidated Membership Interests (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statements Of Consolidated Membership Interest [Abstract]
Interests outstanding	635,000,000	635,000,000	635,000,000
Net effects of cash flow hedges, tax expense	$ 1	$ 1	$ 1
Defined benefit pension plans- net tax benefit		$ 4	$ 33

Description Of Business and Sig

Description Of Business and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Description Of Business And Significant Accounting Policies [Abstract]
DESCRIPTION OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES	1. DESCRIPTION OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES  Description of Business  References in this report to “we,” “our,” “us” and “the company” are to Oncor and/or its subsidiary as apparent in the context. See “Glossary” for definition of terms and abbreviations.  We are a regulated electricity transmission and distribution company principally engaged in providing delivery services to REPs that sell power in the north-central, eastern and western parts of Texas. Revenues from subsidiaries of Vistra (formerly subsidiaries of TCEH) represented 23% , 25% and 25% of our total operating revenues for the years ended December 31, 2016, 2015 and 2014, respectively. We are a direct, majority-owned subsidiary of Oncor Holdings, which is a direct, wholly-owned subsidiary of EFIH, a direct, wholly-owned subsidiary of EFH Corp. EFH Corp. is a subsidiary of Texas Holdings, which is controlled by the Sponsor Group. Oncor Holdings owns 80.03% of our membership interests, Texas Transmission owns 19.75% of our membership interests and certain members of our management team and board of directors indirectly own the remaining membership interests through Investment LLC. We are managed as an integrated business; consequently, there are no separate reportable business segments.  Our consolidated financial statements include our former wholly-owned, bankruptcy-remote financing subsidiary, Bondco, a VIE through December 29, 2016, at which time it was dissolved (see Note 13) . This financing subsidiary was organized for the limited purpose of issuing certain transition bonds to recover generation-related regulatory asset stranded costs and other qualified costs under an order issued by the PUCT in 2002. Bondco issued an aggregate $1.3 billion principal amount of transition bonds during 2003 and 2004. The 2003 Series transition bonds matured and were paid in full in 2015 and the 2004 Series transition bonds matured and were paid in full in May 2016. Final true-up proceedings and refunds of over-collected transition charges for the transition bonds were conducted by Oncor and the PUCT during 2016 and had no material net income impact.  Various “ring-fencing” measures have been taken to enhance the separateness between the Oncor Ring-Fenced Entities and the Texas Holdings Group and our credit quality. These measures serve to mitigate our and Oncor Holdings’ credit exposure to the Texas Holdings Group and to reduce the risk that our assets and liabilities or those of Oncor Holdings would be substantively consolidated with the assets and liabilities of the Texas Holdings Group in connection with a bankruptcy of one or more of those entities, including the EFH Bankruptcy Proceedings discussed below. Such measures include, among other things: our sale of a 19.75% equity interest to Texas Transmission in November 2008; maintenance of separate books and records for the Oncor Ring-Fenced Entities; our board of directors being comprised of a majority of independent directors; and prohibitions on the Oncor Ring-Fenced Entities providing credit support to, or receiving credit support from, any member of the Texas Holdings Group. The assets and liabilities of the Oncor Ring-Fenced Entities are separate and distinct from those of the Texas Holdings Group. None of the assets of the Oncor Ring-Fenced Entities are available to satisfy the debt or contractual obligations of any member of the Texas Holdings Group. We do no t bear any liability for debt or contractual obligations of the Texas Holdings Group, and vice versa. Accordingly, our operations are conducted, and our cash flows are managed, independently from the Texas Holdings Group.  EFH Bankruptcy Proceedings  On the EFH Petition Date, EFH Corp. and the substantial majority of its direct and indirect subsidiaries at the time, including EFIH, EFCH and TCEH, commenced proceedings under Chapter 11 of the U.S. Bankruptcy Code. The Oncor Ring-Fenced Entities are not parties to the EFH Bankruptcy Proceedings. We believe the “ring-fencing” measures discussed above mitigate our potential exposure to the EFH Bankruptcy Proceedings. See Note 2 for a discussion of the potential impacts of the EFH Bankruptcy Proceedings on our financial statements.  Basis of Presentation  Our consolidated financial statements have been prepared in accordance with GAAP. All dollar amounts in the financial statements and tables in the notes are stated in millions of U.S. dollars unless otherwise indicated.  Use of Estimates  Preparation of our financial statements requires management to make estimates and assumptions about future events that affect the reporting of assets and liabilities at the balance sheet dates and the reported amounts of revenue and expense, including fair value measurements. In the event estimates and/or assumptions prove to be different from actual amounts, adjustments are made in subsequent periods to reflect more current information. No material adjustments were made to previous estimates or assumptions during the current year.  Revenue Recognition  General  Oncor’s revenu e is billed under tariffs approved by the PUCT and the majority of revenues are related to providing electric delivery service to consumers. Tariff rates are designed to recover the cost of providing electric delivery service including a reasonable rate of return on invested capital. Revenues are generally recognized when the underlying service has been provided in an amount prescribed by the related tariff.  Reconcilable Tariffs  The PUCT has designated certain tariffs (TCRF, EECRF surcharges, AMS surcharges and charges related to transition bonds) as reconcilable, which means the differences between amounts billed under these tariffs and the related incurred costs are deferred as either regulatory assets or regulatory liabilities. Accordingly, at prescribed intervals, future tariffs are adjusted to either repay regulatory liabilities or collect regulatory assets. See “Regulatory Assets and Liabilities” below.  Impairment of Long-Lived Assets and Goodwill  We evaluate long-lived assets (including intangible assets with finite lives) for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable.  We also evaluate goodwill for impairment annually (at December 1) and whenever events or changes in circumstances indicate that an impairment may exist. The determination of the existence of these and other indications of impairment involves judgments that are subjective in nature and may require the use of estimates in forecasting future results and cash flows.  If at the assessment date our carrying value exceeds our estimated fair value (enterprise value), then the estimated enterprise value is compared to the estimated fair values of our operating assets (including identifiable intangible assets) and liabilities at the assessment date. The resultant implied goodwill amount is compared to the recorded goodwill amount. Any excess of the recorded goodwill amount over the implied goodwill amount is written off as an impairment charge.  The goodwill impairment tests performed in 2016, 2015 and 2014 were based on a qualitative assessment in which we considered macroeconomic conditions, industry and market considerations, cost factors, overall financial performance and other relative factors . Based on tests results, no impairments were recognized in 2016, 2015 or 2014 .  Provision in Lieu of Income Taxes  Effective with the November 2008 sale of equity interests to Texas Transmission and Investment LLC, we became a partnership for U.S. federal income tax purposes, and subsequently we are not a member of EFH Corp.’s consolidated tax group and only EFH Corp.’s share of our partnership income is included in its consolidated federal income tax return. Our tax sharing agreement with Oncor Holdings and EFH Corp. was amended in November 2008 to include Texas Transmission and Investment LLC. The tax sharing agreement provides for the calculation of tax liability substantially as if we and Oncor Holdings were taxed as corporations, and requires tax payments to members determined on that basis (without duplication for any income taxes paid by a subsidiary of Oncor Holdings).  While partnerships are not subject to income taxes, in consideration of the tax sharing agreement and the presentation of our financial statements as an entity subject to cost-based regulatory rate-setting processes, with such costs including income taxes, the financial statements present amounts determined under the tax sharing agreement as “provision in lieu of income taxes” and “liability in lieu of deferred income taxes” for periods subsequent to the sales of equity interests discussed in Note 4. Such amounts are determined in accordance with the provisions of accounting guidance for income taxes and for uncertainty in income taxes and thus differences between the book and tax bases of assets and liabilities are accounted for as if we were taxed as a corporation. The accounting guidance for rate-regulated enterprises requires the recognition of regulatory assets or liabilities if it is probable such deferred tax amounts will be recovered from, or returned to customers in future rates. Investment tax credits are amortized to income over the estimated lives of the related properties.  We classify interest and penalties expense related to uncertain tax positions as current provision in lieu of income taxes as discussed in Note 4.  Defined Benefit Pension Plans and OPEB Plans  We have liabilities under pension plans that offer benefits based on either a traditional defined benefit formula or a cash balance formula and an OPEB plan that offers certain health care and life insurance benefits to eligible employees and their eligible dependents upon the retirement of such employees from the company. Costs of pension and OPEB plans are dependent upon numerous factors, assumptions and estimates. See Note 10 for additional information regarding pension and OPEB plans.  Contingencies  We evaluate and account for contingencies using the best information available. A loss contingency is accrued and disclosed when it is probable that an asset has been impaired or a liability incurred and the amount of the loss can be reasonably estimated. If a range of probable loss is established, the minimum amount in the range is accrued, unless some other amount within the range appears to be a better estimate. If the probable loss cannot be reasonably estimated, no accrual is recorded, but the loss contingency is disclosed to the effect that the probable loss cannot be reasonably estimated. A loss contingency will be disclosed when it is reasonably possible that an asset has been impaired or a liability incurred. If the likelihood that an impairment or incurrence is remote, the contingency is neither accrued nor disclosed. Gain contingencies are recognized upon realization.  System of Accounts  Our accounting records have been maintained in accordance with the FERC Uniform System of Accounts as adopted by the PUCT.  Property, Plant and Equipment  Properties are stated at original cost. The cost of self-constructed property additions includes materials and both direct and indirect labor and applicable overhead and an allowance for funds used during construction.  D epreciation of property, plant and equipment is calculated on a straight-line basis over the estimated service lives of the properties based on depreciation rates approved by the PUCT. As is common in the industry, depreciation expense is recorded using composite depreciation rates that reflect blended estimates of the lives of major asset groups as compared to depreciation expense calculated on a component asset-by-asset basis. Depreciation rates include plant removal costs as a component of depreciation expense, consistent with regulatory treatment. Actual removal costs incurred are charged to accumulated depreciation. When accrued removal costs exceed incurred removal costs, the difference is reclassified as a regulatory liability to retire assets in the future.  Regulatory Assets and Liabilities  Our financial statements reflect regulatory assets and liabilities under cost-based rate regulation in accordance with accounting standards related to the effect of certain types of regulation. Regulatory decisions can have an impact on the recovery of costs, the rate earned on invested capital and the timing and amount of assets to be recovered by rates. See Note 5 for details of regulatory assets and liabilities.  Franchise Taxes  Franchise taxes are assessed to us by local governmental bodies, based on kWh delivered and are the principal component of taxes other than amounts related to income taxes as reported in the income statement. Franchise taxes are not a “pass through” item. The rates we charge customers are intended to recover the franchise taxes, but we are not acting as an agent to collect the taxes from customers.  Allowance for Funds Used During Construction (AFUDC)  AFUDC is a regulatory cost accounting procedu re whereby both interest charges on borrowed funds and a return on equity capital used to finance construction are included in the recorded cost of utility plant and equipment being constructed. AFUDC is capitalized on all projects involving construction periods lasting greater than thirty days. The equity portion, if any, of capitalized AFUDC is accounted for as other income. See Note 13 for detail of amounts charged to interest expense.  Cash and Cash Equivalents  For purposes of reporting cash and cash equivalents, temporary cash investments purchased with a remaining maturity of three months or less are considered to be cash equivalents. See Note 13 for details regarding restricted cash.  Fair Value of Nonderivative Financial Instruments  The carrying amounts for financial assets classified as current assets and the carrying amounts for financial liabilities classified as current liabilities approximate fair value due to the short maturity of such instruments. The fair values of other financial instruments, for which carrying amounts and fair values have not been presented, are not materially different than their related carrying amounts. The following discussion of fair value accounting standards applies primarily to our determination of the fair value of assets in the pension and OPEB plans trusts (see Note 10) and long-term debt (see Note 7).  Accounting standards related to the determination of fair value define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. We use a “mid-market” valuation convention (the mid-point price between bid and ask prices) as a practical expedient to measure fair value for the majority of our assets and liabilities subject to fair value measurement on a recurring basis. We primarily use the market approach for recurring fair value measurements and use valuation techniques to maximize the use of observable inputs and minimize the use of unobservable inputs.  We categorize our assets and liabilities recorded at fair value based upon the following fair value hierarchy:  · Level 1 valuations use quoted prices in active markets for identical assets or liabilities that are accessible at the measurement date. An active market is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis.  · Level 2 valuations use inputs that, in the absence of actively quoted market prices, are observable for the asset or liability, either directly or indirectly. Level 2 inputs include: (a) quoted prices for similar assets or liabilities in active markets , (b) quoted prices for identical or similar assets or liabilities in markets that are not active, (c) inputs other than quoted prices that are observable for the asset or liability such as interest rates and yield curves observable at commonly quoted intervals and (d) inputs that are derived principally from or corroborated by observable market data by correlation or other means. Our Level 2 valuations utilize over-the-counter broker quotes, quoted prices for similar assets or liabilities that are corroborated by correlations or other mathematical means and other valuation inputs.  · Level 3 valuations use unobservable inputs for the asset or liability. Unobservable inputs are used to the extent observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date. We use the most meaningful information available from the market combined with internally developed valuation methodologies to develop our best estimate of fair value.  We utilize several different valuation techniques to measure the fair value of assets and liabilities, relying primarily on the market approach of using prices and other market information for identical and/or comparable assets and liabilities for those items that are measured on a recurring basis.  The fair value of certain investments is measured using the net asset value (NAV) per share as a practical expedient. Such investments measured at NAV are not required to be categorized within the fair value hierarchy. See “Changes in Accounting Standards” below.  Consolidation of Variable Interest Entities  A VIE is an entity with which we have a relationship or arrangement that indicates some level of control over the entity or results in economic risks to us. We consolidate a VIE if we have: a) the power to direct the significant activities of the VIE and b) the right or obligation to absorb profit and loss from the VIE (primary beneficiary). See Note 13.  Derivative Instruments and Mark-to-Market Accounting  We have from time-to-time entered into derivative instruments to hedge interest rate risk. If the instrument meets the definition of a derivative under accounting standards related to derivative instruments and hedging activities, the fair value of each derivative is recognized on the balance sheet as a derivative asset or liability and changes in the fair value are recognized in net income, unless criteria for certain exceptions are met. This recognition is referred to as “mark-to-market” accounting. Changes in Accounting Standards  In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update 2016-2 (ASU 2016-2), Leases . ASU 2016-2 amends previous GAAP to require the balance sheet recognition of lease assets and liabilities for operating leases. We will be required to adopt ASU 2016-2 by January 1, 2019 and do not expect to early adopt. Retrospective application to the 2017 and 2018 comparative periods presented will be required in the year of adoption. The recognition of any lease obligation on the balance sheet will be classified as long-term debt for GAAP purposes and is defined as debt for our regulatory capital structure purposes (See Note 9 for details). Although any lease obligation will affect our balance sheet and capitalization ratios, the impact is not expected to be material. We continue to evaluate the impact of ASU 2016-2 on our financial statements.  Since May 2014, the FASB has issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers along with other supplemental guidance (together, Topic 606). Topic 606 introduces new, increased requirements for disclosure of revenue in financial statements and guidance that are intended to eliminate inconsistencies in the recognition of revenue. We will be required to adopt Topic 606 by January 1, 2018 and do not expect to early adopt. Our revenues from customers are tariff-based and are designed to recover the cost of providing electric delivery service to customers including a reasonable rate of return on invested capital. Revenues are generally recognized when the underlying service has been provided in an amount prescribed by the related tariff. At this time, we do not expect the new guidance to change this pattern of recognition and therefore it is not expected to have a material effect on our reported results of operations, financial condition or cash flows. We continue to evaluate the a pplication of the new guidance.  In May 2015, the FASB issued a new accounting standards update (ASU 2015-07), which removed the requirement to categorize within the fair value hierarchy all investments for which fair value is measured using the net asset value per share practical expedient. ASU 2015-07 is effective for fiscal years beginning after December 15, 2015 and was retrospectively adopted effective December 31, 2016. T he adoption impacted fair value measurement disclosures related to our pension and OPEB plans. See Note 10 - Pension and OPEB Plans.

EFH Bankruptcy Proceedings

EFH Bankruptcy Proceedings	12 Months Ended
	Dec. 31, 2016
EFH Bankruptcy Proceedings [Abstract]
EFH BANKRUPTCY PROCEEDINGS	2. EFH BANKRUPTCY PROCEEDINGS  On the EFH Petition Date, EFH Corp. and the substantial majority of its direct and indirect subsidiaries at the time, including EFIH, EFCH and TCEH, commenced proceedings under Chapter 11 of the U . S . Bankruptcy Code. The Oncor Ring-Fenced Entities are not parties to the EFH Bankruptcy Proceedings. We believe the “ring-fencing” measures discussed above mitigate our potential exposure to the EFH Bankruptcy Proceedings. See Note 1 and below for further information regarding the EFH Bankruptcy Proceedings and the proposed change in control of our indirect majority owner in connection with such proceedings. The U . S . Bankruptcy Code automatically enjoined, or stayed, us from judicial or administrative proceedings or filing of other actions against our affiliates or their property to recover, collect or secure our claims arising prior to the EFH Petition Date. Following the EFH Petition Date, EFH Corp. received approval from the bankruptcy court to pay or otherwise honor certain prepetition obligations generally designed to stabilize its operations. Included in the approval were the obligations owed to us representing our prepetition electricity delivery fees. As of December 31, 2016, we had collected our prepetition receivables from the Texas Holdings Group of approximately $129 million. As discussed below, the New Plan of Reorganization (defined below) provided for a spin-off of the TCEH Debtors from EFH Corp. As a result of this spin-off, Vistra and its subsidiaries, including Luminant and TXU Energy, ceased to be affiliates of ours as of October 3, 2016.  T he EFH Bankruptcy Proceedings continue to be a complex litigation matter and the full extent of potential impacts on us remain unknown. We will continue to evaluate our affiliate transactions and contingencies throughout the EFH Bankruptcy Proceedings to determine any risks and resulting impacts on our results of operations, financial statements and cash flows.  See Note 1 2 for details of Oncor’s related-party transactions with members of the Texas Holdings Group.  Potential Change in Indirect Ownership of Oncor  As part of the EFH Bankruptcy Proceedings, the bankruptcy court confirmed the Debtors’ Sixth Amended Plan of Reorganization by order dated December 9, 2015. In general, among other things, the Sixth Amended Plan of Reorganization provided for a series of transactions to be effected pursuant to a merger and purchase agreement (Hunt Merger and Purchase Agreement) with an investor group consisting of certain unsecured creditors of TCEH and an affiliate of Hunt Consolidated, Inc. (Hunt), as well as certain other investors designated by Hunt (collectively, the Hunt Investor Group), that would have led to a significant change in the indirect equity ownership of Oncor.  The Debtors and certain creditors entered into a Plan Support Agreement (as amended, Plan Support Agreement) that provided for, among other things, their respective obligations to act and/or support Plans of Reorganization. On May 1, 2016, certain first lien creditors of TCEH delivered a written notice (Plan Support Termination Notice) to the Debtors and the other parties to the Plan Support Agreement notifying such parties of the occurrence of a Plan Support Termination Event (as defined in the Plan Support Agreement). The delivery of the Plan Support Agreement Termination Notice caused the Sixth Amended Plan of Reorganization to become null and void.  On May 1, 2016, following receipt of the Plan Support Termination Notice, EFH Corp. and EFIH delivered a written notice (Merger and Purchase Agreement Termination Notice) to the Hunt Investor Group notifying the Hunt Investor Group that EFH Corp. and EFIH terminated the Hunt Merger and Purchase Agreement. The termination of the Hunt Merger and Purchase Agreement also caused the automatic termination (without the necessity of further action) of (i) certain agreements defining the investment obligations of certain Hunt Investor Group members, and (ii) a letter agreement between Oncor and the Hunt Investor Group.  Following the occurrence of the Plan Support Termination Event as described above, the Debtors filed a new joint Plan of Reorganization (New Plan of Reorganization) pursuant to Chapter 11 of the Bankruptcy Code and a related disclosure statement with the bankruptcy court on May 1, 2016.  The New Plan of Reorganization provides that the confirmation and effective date of the New Plan of Reorganization with respect to the TCEH Debtors may occur (and on October 3, 2016, it did occur) separate from, and independent of, the confirmation and effective date of the New Plan of Reorganization with respect to the EFH Debtors. The New Plan of Reorganization, subject to certain conditions and required regulatory approvals, provides for, among other things: · with respect to the TCEH Debtors, either (a) a tax-free spin-off from EFH Corp., including a transaction that will result in a partial step-up in the tax basis of certain TCEH assets distributed to a newly formed entity wholly owned by TCEH, or (b) a taxable transaction that results in the assets of the TCEH Debtors being distributed to a newly formed entity wholly owned by the entity now known as Vistra (TCEH Transactions), and · with respect to the EFH Debtors, the reorganization of EFH Corp. and EFIH (Reorganized EFH) either pursuant to (a) an equity investment (which may be from existing creditors or third-party investors) or (b) pursuant to a standalone plan of reorganization, in which creditors receive shares of common stock of Reorganized EFH. Solely as it pertains to the TCEH Debtors, the disclosure statement was approved by the bankruptcy court on June 17, 2016 . The bankruptcy court confirmed the New Plan of Reorganization with respect to the TCEH Debtors on August 26, 2016, and it became effective by its terms, and the Vistra Spin-Off occurred effective October 3, 2016.  On July 29, 2016, (i) the EFH Debtors entered into a Plan Support Agreement (NEE Plan Support Agreement) with NEE to effect an agreed upon restructuring of the EFH Debtors pursuant to an amendment to the New Plan of Reorganization (Amended New Plan) and (ii) EFH Corp. and EFIH entered into an Agreement and Plan of Merger (NEE Merger Agreement) with NEE and EFH Merger Co., LLC (Merger Sub), a wholly-owned subsidiary of NEE. Pursuant to the NEE Merger Agreement, at the effective time of the Amended New Plan with respect to the EFH Debtors, EFH Corp. will merge with and into Merger Sub (NEE Merger) with Merger Sub surviving as a wholly owned subsidiary of NEE.  In August 2016, the EFH Debtors filed a motion seeking bankruptcy court approval of entry into the NEE Merger Agreement, a related termination fee and the NEE Plan Support Agreement. The NEE Merger Agreement includes various conditions precedent to consummation of the transactions contemplated thereby, including, among others, a condition that certain approvals and rulings be obtained, including from, among others, the PUCT and the IRS and a condition that the TCEH Transactions have occurred. NEE will not be required to consummate the NEE Merger if, among other items, the PUCT approval is obtained but with conditions, commitments or requirements that impose a Burdensome Condition (as defined in the NEE Merger Agreement). NEE’s and Merger Sub’s obligations under the NEE Merger Agreement are not subject to any financing condition. The bankruptcy court approved EFH Corp. and EFIH’s entry into the NEE Merger Agreement, the related termination fee, and the NEE Plan Support Agreement by order dated September 19, 2016.  Following approval of the NEE Merger Agreement by the bankruptcy court and until confirmation of the Amended New Plan by the bankruptcy court, EFH and EFIH were permitted to continue or have discussions or negotiations with respect to acquisition proposals for Reorganized EFH (x) with persons that were in active negotiation at the time of approval of the NEE Merger Agreement by the bankruptcy court and (y) with persons that submitted an unsolicited acquisition proposal that is, or is reasonably likely to lead to, a Superior Proposal (as defined in the NEE Merger Agreement).  The NEE Merger Agreement may be terminated upon certain events, including, among other things: · by either party, if the NEE Merger is not consummated by March 26, 2017, subject to a 90 -day extension under certain conditions; or  · by EFH Corp. or EFIH, until the entry of the confirmation order of the Amended New Plan with respect to the EFH Debtors, if their respective board of directors or managers determines after consultation with its independent financial advisors and outside legal counsel, and based on advice of such counsel, that the failure to terminate the NEE Merger Agreement is inconsistent with its fiduciary duties; provided that a material breach of EFH Corp.’s or EFIH’s obligations under certain provisions of the NEE Merger Agreement has not provided the basis for such determination.  If the NEE Merger Agreement is terminated for certain reasons set forth therein and an alternative transaction is consummated by EFH or EFIH in which neither NEE nor any of its affiliates obtains direct or indirect ownership of approximately 80% of Oncor, then EFH and EFIH will pay a termination fee of $275,000,000 to NEE.  Following the execution and delivery of the NEE Merger Agreement, EFIH requested, pursuant to the NEE Merger Agreement, that Oncor Holdings and Oncor enter into a letter agreement (NEE Letter Agreement) with NEE and Merger Sub. The NEE Letter Agreement was executed on August 4, 2016 and sets forth certain rights and obligations of the Oncor Ring-Fenced Entities, NEE and Merger Sub to cooperate in the manner set forth therein with respect to initial steps to be taken in connection with the acquisition of Reorganized EFH (EFH Acquisition) and the other transactions described in the NEE Merger Agreement.  The NEE Letter Agreement is not intended to give NEE or Merger Sub, directly or indirectly, the right to control or direct the operations of any of the Oncor Ring-Fenced Entities prior to the receipt of all approvals required by the bankruptcy court, the PUCT and other governmental entities and the consummation of the EFH Acquisition and related transactions (if and when such transactions are consummated). In addition, Oncor Holdings and Oncor have not endorsed or approved any restructuring involving Oncor Holdings or Oncor or any other transaction proposed by NEE or Merger Sub involving Oncor Holdings or Oncor. On October 29, 2016, we entered into an Interest Purchase Agreement (OMI Agreement) with T & D Equity Acquisition, LLC, a wholly-owned subsidiary of NEE (T&D Equity Acquisition) and Investment LLC pursuant to which T&D Equity Acquisition would purchase the 1,396,008 limited liability company interests of Oncor (representing approximately 0.22% of the outstanding equity of Oncor) that Investment LLC owns in exchange for a purchase price of approximately $27 million. The OMI Agreement contains various conditions precedent to consummation of the transactions contemplated thereby, including the consummation of the transactions contemplated by the NEE Merger Agreement.  On October 30, 2016, an affiliate of NEE entered into an Agreement and Plan of Merger (the TTI Merger Agreement) with Texas Transmission Holdings Corporation (the parent of Texas Transmission) and certain of its affiliates to purchase Texas Transmission’s 19.75% equity interest in Oncor for approximately $2.4 billion. The parties have agreed to use their best efforts to have the TTI Merger Agreement close contemporaneously with the NEE Merger. The TTI Merger Agreement also contains various conditions precedent to consummation of the transactions contemplated thereby, including a requirement that EFH Corp., subject to bankruptcy court approval, waive its rights of first refusal under the Investor Rights Agreement to purchase Texas Transmission’s 19.75% equity interest in Oncor.  The confirmation hearing for the New Plan of Reorganization as it relates to the EFH Debtors was scheduled to commence on December 1, 2016. On November 17, 2016, however, the United States Court of Appeals for the Third Circuit (the Third Circuit) issued an opinion regarding the claims of the EFIH first and second lien noteholders regarding claims for makewhole payments (the Makewhole Claims). As a result of this opinion, the Debtors could no longer satisfy the Amended New Plan condition precedent to closing related to the Makewhole Claims. As a result, Debtors determined to adjourn the plan confirmation hearing to allow time to engage in further discussions with key creditor constituencies and NEE.  On December 1, 2016, the Debtors filed the Fifth Amended Joint Plan of Reorganization of Energy Future Holdings Corp., et. al., p ursuant to Chapter 11 of the Bankruptcy Code (as subsequently amended by the Sixth, Seventh and Eighth Amended Plans of Reorganization, the Further Amended New Plan) and the related disclosure statement. The Further Amended New Plan deleted the condition related to the Makewhole Claims, and made certain other modifications. The Debtors also filed a motion seeking to re-solicit the votes of certain classes of claims as a result of these modifications. The Bankruptcy Court held a hearing on January 4, 2017, at which time it approved the disclosure statement and scheduled a confirmation hearing on the Further Amended New Plan to begin on February 14, 2017. After three days of argument and testimony, the Bankruptcy Court confirmed the Further Amended New Plan on February 17, 2017.  Notwithstanding these pending transactions, we cannot predict the ultimate outcome of the EFH Bankruptcy Proceedings, including whether the transactions contemplated by the Further Amended New Plan, including the EFH Acquisition, will (or when they will) close. Although the Further Amended New Plan has been confirmed by the Bankruptcy Court, there remain conditions to the Further Amended New Plan becoming effective and the consummation of the EFH Acquisition, including, without limitation, certain regulatory approvals pending with the PUCT, as described below under “–Regulatory Matters Related to EFH Bankruptcy Proceedings.” As a result, we remain unable to predict how any reorganization of EFH Corp. and EFIH ultimately will impact Oncor or what form any change in indirect ownership of Oncor may take.  Regulatory Matters Related to EFH Bankruptcy Proceedings  In September 2015, Oncor and the Hunt Investor Group filed in PUCT Docket No. 45188 a joint application with the PUCT seeking certain regulatory approvals with respect to the transactions contemplated by the Sixth Amended Plan of Reorganization. On March 24, 2016, the PUCT issued an order conditionally approving the joint application. On April 18, 2016, the Hunt Investor Group and certain interveners in PUCT Docket No. 45188 filed motions for rehearing and on May 19, 2016, the PUCT denied such motions and the order became final. The Hunt Investor Group filed a petition with the Travis County District Court on June 17, 2016 seeking review of the order. We cannot predict the results of the review or the ultimate disposition of PUCT Docket No. 45188, particularly in light of the termination of the Sixth Amended Plan of Reorganization and the other pending transactions discussed above.  In connection with PUCT Docket No. 45188, certain cities that have retained original jurisdiction over electric utility rates passed resolutions directing Oncor to file rate review proceedings. In connection with those resolutions, counsel for those cities has notified Oncor that they expect Oncor to make a rate filing to comply with their resolutions on or before March 17, 2017. For more information, see Note 3 – “City Rate Reviews”. The NEE Merger Agreement contemplates that Oncor and NEE file a joint application with the PUCT seeking certain regulatory approvals with respect to the transactions contemplated by the Amended New Plan. Oncor and NEE filed that joint application in PUCT Docket No. 46238 in October 2016 and a ruling with respect to such application is expected by late April 2017. Regulatory approvals with respect to the transactions contemplated by the Amended New Plan were also the subject of an application filed by Oncor and NEE with FERC. FERC issued an order conditionally approving the transactions in February 2017.  Settlement Agreement  In connection with the EFH Bankruptcy Proceedings, the EFH Debtors and various creditor parties entered into a settlement agreement (the Settlement Agreement) in August 2015 (as amended in September 2015) to compromise and settle, among other things (a) intercompany claims among the EFH Debtors, (b) claims and causes of actions against holders of first lien claims against TCEH and the agents under the TCEH Senior Secured Facilities, (c) claims and causes of action against holders of interests in EFH Corp. and certain related entities and (d) claims and causes of action against each of the EFH Debtors’ current and former directors, the Sponsor Group, managers and officers and other related entities. The Settlement Agreement contemplates a release of such claims upon approval of the Settlement Agreement by the bankruptcy court, which approval was obtained in December 2015.  The Settlement Agreement settles substantially all inter-debtor claims through the effective date of the Settlement Agreement. These settled claims include potentially contentious inter-debtor claims, including various potential avoidance actions and claims arising under numerous debt agreements, tax sharing agreements, and contested property transfers. The release provisions of the Settlement Agreement took effect immediately upon the entry of the bankruptcy court order approving the Settlement Agreement. In this regard, substantially all of the potential affiliate claims, derivative claims and other types of disputes among affiliates (including claims against Oncor) have been resolved by bankruptcy court order. Accordingly, we believe the Settlement Agreement resolves all affiliate claims against Oncor and its assets existing as of the effective date of the Settlement Agreement.

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2016
Regulatory Matters [Abstract]
REGULATORY MATTERS	 3. REGULATORY MATTERS  Change in Control Reviews  In September 2015, Oncor and the Hunt Investor Group filed in PUCT Docket No. 45188 a joint application with the PUCT seeking certain regulatory approvals with respect to the transactions contemplated by the Sixth Amended Plan of Reorganization. On March 24, 2016, the PUCT issued an order conditionally approving the joint application. On April 18, 2016, the Hunt Investor Group and certain interveners in PUCT Docket No. 45188 filed motions for rehearing and on May 19, 2016, the PUCT denied such motions and the order became final. The Hunt Investor Group filed a petition with the Travis County District Court on June 17, 2016 seeking review of the order. We cannot predict the results of the review or the ultimate disposition of PUCT Docket No. 45188, particularly in light of the termination of the Sixth Amended Plan of Reorganization and the other pending transactions discussed in Note 2 to Financial Statements. For additional information regarding the Sixth Amended Plan of Reorganization and application for regulatory approval, see Note 2 to Financial Statements and “City Rate Reviews” below.  The NEE Merger Agreement contemplates that Oncor and NEE file a joint application with the PUCT seeking certain regulatory approvals with respect to the transactions contemplated by the Amended New Plan. Oncor and NEE filed that joint application in PUCT Docket No. 46238 in October 2016 and a ruling with respect to such application is expected by late April 2017. Regulatory approvals with respect to the transactions contemplated by the Amended New Plan were also the subject of an application filed by Oncor and NEE with FERC. FERC issued an order conditionally approving the transactions in February 2017. For additional information regarding the NEE Merger Agreement and Amended New Plan (including its subsequent amendment by the Further Amended New Plan) , see Note 2 to Financial Statements.  City Rate Reviews  Oncor received resolutions passed by 58 cities with original jurisdiction over electric utility rates directing Oncor to file rate review proceedings. The resolutions passed required Oncor to file a rate review with each city by September 1, 2016 based on a January 1, 2015 to December 31, 2015 test year. However, Oncor was subsequently notified by counsel representing these cities that these rate review proceedings had been suspended indefinitely, pending resolution of Oncor ownership issues. The notice provided that if and when the cities desire to proceed with a rate inquiry, cities would notify Oncor in writing and inform Oncor of a precise date of the rate case, which would be at least 120 days from receipt of the communication that lifts the suspension. On November 17, 2016, counsel representing these cities notified Oncor that the cities were lifting that suspension and expect Oncor to make a rate filing to comply with their resolutions on or before March 17, 2017. The notice requires that Oncor’s rate filing be based on an historical test year consisting of the most recent period for which data is available.  2008 Rate Review  In August 2009, the PUCT issued a final order with respect to our June 2008 rate review filing with the PUCT and 204 cities based on a test year ended December 31, 2007 (PUCT Docket No. 35717), and new rates were implemented in September 2009. We and four other parties appealed various portions of the rate review final order to a state district court. In January 2011, the district court signed its judgment reversing the PUCT with respect to two issues: the PUCT’s disallowance of certain franchise fees and the PUCT’s decision that PURA no longer requires imposition of a rate discount for state colleges and universities. We filed an appeal with the Texas Third Court of Appeals (Austin Court of Appeals) in February 2011 with respect to the issues we appealed to the district court and did not prevail upon, as well as the district court’s decision to reverse the PUCT with respect to discounts for state colleges and universities. In early August 2014, the Austin Court of Appeals reversed the district court and affirmed the PUCT with respect to the PUCT’s disallowance of certain franchise fees and the PUCT’s decision that PURA no longer requires imposition of a rate discount for state colleges and universities. The Austin Court of Appeals also reversed the PUCT and district court’s rejection of a proposed consolidated tax savings adjustment arising out of EFH Corp.’s ability to offset our taxable income against losses from other investments and remanded the issue to the PUCT to determine the amount of the consolidated tax savings adjustment. In late August 2014, we filed a motion on rehearing with the Austin Court of Appeals with respect to certain appeal issues on which we were not successful, including the consolidated tax savings adjustment. In December 2014, the Austin Court of Appeals issued its opinion, clarifying that it was rendering judgment on the rate discount for state colleges and universities issue (affirming that PURA no longer requires imposition of the rate discount) rather than remanding it to the PUCT, and dismissing the motions for rehearing regarding the franchise fee issue and the consolidated tax savings adjustment. We filed a petition for review with the Texas Supreme Court in February 2015. The Texas Supreme Court granted the petition for review and heard oral arguments in September 2016. On January 6, 2017, the Texas Supreme Court issued its opinion, unanimously ruling as follows on the three issues before it:  · Consolidated tax savings adjustment - The Supreme Court reversed the Court of Appeals and upheld the PUCT’s decision not to make a consolidated tax savings adjustment, concluding that the PUCT had properly applied PURA Section 36.060 and that Oncor no longer met the statutory criteria for imposition of such an adjustment.  · State colleges and universities rate discount - The Supreme Court upheld the Court of Appeals’ and the PUCT’s decisions that no such discount was proper, concluding that PURA Section 36.351 requires a discount only for the provision of electric service and that, upon the start of retail competition, electric service is provided to end-use customers by REPs and not TDUs.  · Municipal franchise fees - The Supreme Court reversed the Court of Appeals’ and the PUCT’s disallowance of certain franchise fees, ruling that the relevant PURA provision did not limit negotiated franchise fees to a one-time opportunity upon the expiration of a franchise that was in effect on September 1, 1999, but that such renegotiations may take place at any time.  T he Texas Supreme Court issued its mandate on February 16, 201 7 . On February 17, 201 7 , Oncor filed a tariff modification with the PUCT to immediately remove the state colleges and universities discount rider, and on February 23, 2017, the PUCT opened Docket No. 46884 to consider the remand from the Texas Supreme Court. That docket will consider recovery of municipal franchise fees, as well as a cash working capital issue that Oncor prevailed upon at the Court of Appeals and which was not appealed to the Texas Supreme Court. We are involved in various other regulatory proceedings in the normal course of business, the ultimate resolution of which, in the opinion of management, should not have a material effect upon our financial position, results of operations or cash flows. 

Provision In Lieu Of Income Tax

Provision In Lieu Of Income Taxes	12 Months Ended
	Dec. 31, 2016
Provision In Lieu Of Income Taxes [Abstract]
PROVISION IN LIEU OF INCOME TAXES	4. PROVISION IN LIEU OF I NCOME TAXES  The components of our reported provision (benefit) in lieu of income taxes are as follows:   Year Ended December 31,  2016 2015 2014   Reported in operating expenses:  Current:  U.S. federal $ 60 $ 189 $ 113  State 20 32 24  Deferred:  U.S. federal 181 55 146  State - (13) -  Amortization of investment tax credits (2) (3) (3)  Total reported in operating expenses 259 260 280  Reported in other income and deductions:  Current:  U.S. federal (5) (7) (4)  State - - -  Deferred federal - (1) 2  Total reported in other income and deductions (5) (8) (2)  Total provision in lieu of income taxes $ 254 $ 252 $ 278  Reconciliation of provision in lieu of income taxes computed at the U.S. federal statutory rate to provision in lieu of income taxes:     Year Ended December 31,  2016 2015 2014   Income before provision in lieu of income taxes $ 685 $ 684 $ 728  Provision in lieu of income taxes at the U.S. federal statutory rate of 35% $ 240 $ 239 $ 255  Amortization of investment tax credits – net of deferred tax effect (2) (3) (3)  Amortization (under regulatory accounting) of statutory tax rate changes (1) (1) (2)  Amortization of Medicare subsidy regulatory asset - - 14  Texas margin tax, net of federal tax benefit 13 13 16  Nondeductible losses (gains) on benefit plan investments - - (2)  Other, including audit settlements 4 4 -  Reported provision in lieu of income taxes $ 254 $ 252 $ 278  Effective rate 37.1% 36.8% 38.2%  The net amounts of $ 2. 788 billion and $2. 612 billion reported in the balance sheets at December 31, 201 6 and 201 5 , respectively, as liability in lieu of deferred income taxes include amounts previously recorded as net deferred tax liabilities. Upon the sale of equity interests to Texas Transmission and Investment LLC in 2008, we became a partnership for U . S . federal income tax purposes, and the temporary differences that gave rise to the deferred taxes will, over time, become taxable to the equity holders. Under a tax sharing agreement among us and our equity holders (see Note 1), we make payments to the equity holders related to income taxes when amounts would have become due to the IRS if Oncor was taxed as a corporation . Accordingly, as the temporary differences become taxable, we will pay the equity holders. In the event such amounts are not paid under the tax sharing agreement, it is probable that this regulatory liability will continue to be included in Oncor’s rate setting processes .  Accounting For Uncertainty in Provision in Lieu of Income Taxes  Prior to November 2008, we were a member of the EFH Corp. consolidated tax group. The examination and applicable appeals process of EFH Corp. and its subsidiaries’ federal income tax returns for the years ending prior to January 1, 2009 are complete, but final settlement of those years is not expected until EFH Corp. finalizes any claims with the IRS for those years in the bankruptcy process. Texas franchise and margin tax returns are under examination or still open for examination for tax years beginning after 2006. Subsequent to November 2008, we are not a member of the EFH Corp. consolidated federal tax group and assess our liability for uncertain tax positions in our partnership returns.  In the first quarter of 2014, several uncertain tax positions were remeasured under GAAP guidance as a result of new information received from the IRS with respect to the audit of tax years 2007 through 2009. As a result, we reduced the liability for uncertain tax positions by $18 million. This reduction consisted of a $16 million increase in liability in lieu of deferred income taxes and a $2 million ( $1 million after tax) reversal of accrued interest, which is reported as a decrease in provision in lieu of income taxes. In September 2014, EFH Corp. signed the final agreed Revenue Agent Report and associated documentation (RAR) for the 2007 tax year and filed and received approval of the bankruptcy court in the EFH Bankruptcy Proceedings of its signing of the RAR. With the signing of the RAR in the third quarter of 2014, the remaining $1 million liability for uncertain tax positions with respect to tax year 2007 was released. The reduction consisted of a $1 million reversal of provision in lieu of income taxes. Final processing of the agreed RAR continues. The impact related to the conclusion of the 200 7 audit is a deferred tax asset of approximately $45 million that is recorded in liability in lieu of deferred income taxes .  In the fourth quarter of 2014, the Department of Justice filed a claim with the bankruptcy court for open tax years through 2013 that was consistent with the settlement EFH Corp. reached with the IRS for tax years 2003 through 2006. As a result of this filing, the 2003 through 2006 open tax years for GAAP purposes were settled and the liability for uncertain tax positions was reduced by $35 million. The impact related to the conclusion of the 2003 through 2006 audit is approximately $11 million and is recorded as a deferred tax asset in liability in lieu of deferred income taxes. In the second quarter of 2015, EFH Corp. received the final RAR and associated documentation for the 2008 tax year which includes the results of Oncor. In addition, we received the final RAR and associated documentation for tax years 2008 and 2009 in which we filed a partnership tax return. The RARs reflect additional deductions for Oncor resulting in approximately $8 million in tax refunds from our members. Of this amount, $4 million is related to pre-partnership formation and is recorded as a deferred tax asset in liability in lieu of deferred income taxes and $4 million is related to post-partnership formation and was collected during the third quarter of 2015.  The following table summarizes the changes to the uncertain tax positions reported in other noncurrent liabilities in our consolidated balance sheet during the years ended December 31, 2016, 2015 and 2014:   2016 2015 2014   Balance at January 1, excluding interest and penalties $ 3 $ 2 $ 54  Additions based on tax positions related to prior years - - -  Reductions based on tax positions related to prior years - - (16)  Settlements with taxing authorities - 1 (36)  Balance at December 31, excluding interest and penalties $ 3 $ 3 $ 2  Of the balances at both December 31, 2016 and 201 5 , $3 million represent s tax positions for which the uncertainty relates to the timing of recognition for tax purposes. The disallowance of such positions would not affect the effective tax rate, but would accelerate the payment of cash under the tax sharing agreement to an earlier period.  Noncurrent liabilities included no accrued interest related to uncertain tax positions at December 31, 2016 and 2015. There were no amounts recorded related to interest and penalties in the year ended December 31, 2016 and 2015 and benefits of $1 million for the year ended December 31, 2014 (amount is after tax). The federal income tax benefit on the interest accrued on uncertain tax positions is recorded as liability in lieu of deferred income taxes.

Regulatory Assets and Liabiliti

Regulatory Assets and Liabilities	12 Months Ended
	Dec. 31, 2016
Regulatory Assets and Liabilities [Abstract]
REGULATORY ASSETS AND LIABILITIES	5. REGULATORY ASSETS AND LIABILITIES  Recognition of regulatory assets and liabilities and the amortization periods over which they are expected to be recovered or refunded through rate regulation reflect the decisions of the PUCT. Components of our regulatory assets and liabilities are provided in the table below. Amounts not earning a return through rate regulation are noted.   Remaining Rate Recovery/Amortization Period at Carrying Amount At  December 31, 2016 December 31, 2016 December 31, 2015   Regulatory assets:  Generation-related regulatory assets securitized by transition bonds (a)(d) - $ - $ 31  Employee retirement costs being amortized 3 years 23 38  Unrecovered employee retirement costs incurred since the last rate review period (b) To be determined 327 291  Employee retirement liability (a)(b)(c) To be determined 849 853  Self-insurance reserve (primarily storm recovery costs) being amortized 3 years 64 95  Unrecovered self-insurance reserve incurred since the last rate review period (b) To be determined 367 332  Securities reacquisition costs (post-industry restructure) Lives of related debt 13 9  Recoverable amounts in lieu of deferred income taxes Life of related asset or liability 2 12  Deferred conventional meter and metering facilities depreciation Largely 4 years 78 100  Under-recovered AMS costs To be determined 205 164  Energy efficiency performance bonus (a) 1 year or less 10 10  Other regulatory assets Various 36 23  Total regulatory assets 1,974 1,958   Regulatory liabilities:  Estimated net removal costs Lives of related assets 819 686  Investment tax credit and protected excess deferred taxes Various 10 14  Over-collection of transition bond revenues (a)(d) - - 29  Over-recovered wholesale transmission service expense (a) 1 year or less 10 24  Other regulatory liabilities Various 17 11  Total regulatory liabilities 856 764  Net regulatory asset (e) $ 1,118 $ 1,194 ____________ (a) Not earning a return in the regulatory rate-setting process. (b) Recovery is specifically authorized by statute or by the PUCT, subject to reasonableness review. (c) Represents unfunded liabilities recorded in accordance with pension and OPEB accounting standards. (d) Bondco net regulatory liabilities at December 31, 2016 were zero . Bondco net regulatory assets of $10 million at December 31, 2015 consisted of $31 million included in generation-related regulatory assets net of the regulatory liability for over-collection of transition bond revenues of $21 million (excludes $8 million of over-collections related to transition bonds assumed by Oncor for final settlement). (e) For year-end 2016, regulatory assets and liabilities are presented gross on the balance sheet. In August 2011, the PUCT issued a final order in our rate review filed in January 2011. The rate review included a determination of the recoverability of regulatory assets at June 30, 2010, including the recoverability period of those assets deemed allowable by the PUCT.  In accordance with the PUCT’s August 2009 order in our rate review, the remaining net book value and the approved amount of removal cost of existing conventional meters that were replaced by advanced meters are being charged to depreciation and amortization expense over an 11 -year cost recovery period.  In September 2008, the PUCT approved a settlement for us to recover our estimated future investment for advanced metering deployment. We began billing the AMS surcharge in the January 2009 billing month cycle. The surcharge is expected to total $1.023 billion over the 11 -year recovery period and includes a cost recovery factor of $2.19 per month per residential retail customer and $2.39 to $5.15 per month for non-residential retail customers. We account for the difference between the surcharge billings for advanced metering facilities and the allowable revenues under the surcharge provisions, which are based on expenditures and an allowed return, as a regulatory asset or liability. Such differences arise principally as a result of timing of expenditures or cost increases . As indicated in the table above, the regulatory asset at December 31, 201 6 and 201 5 totaled $205 million and $164 million, respectively.  As a result of acquisition accounting , in 2007 the carrying value of certain generation-related regulatory assets securitized by transition bonds, which have been reviewed and approved by the PUCT for recovery but without earning a rate of return, was reduced by $213 million. This amount was being accreted to other income over the recovery period that was remaining at October 10, 2007 (approximately nine years) which ended in 2016 .

Borrowings Under Credit Facilit

Borrowings Under Credit Facilities	12 Months Ended
	Dec. 31, 2016
Borrowings Under Credit Facilities [Abstract]
BORROWINGS UNDER CREDIT FACILITIES	6. BORROWINGS UNDER CREDIT FACILITIES  At December 31, 2016, we had a $2.0 billion secured revolving credit facility to be used for working capital and general corporate purposes, issuances of letters of credit and support for any commercial paper issuances. In October 2016, we exercised the second of two one -year extensions available to us and extended the term of the revolving credit facility to October 2018 . The terms of the revolving credit facility allow us to request an increase in our borrowing capacity of $100 million in the aggregate provided certain conditions are met, including lender approval.  Borrowings under the revolving credit facility are classified as short-term on the balance sheet and are secured equally and ratably with all of our other secured indebtedness by a first priority lien on property we acquired or constructed for the transmission and distribution of electricity. The property is mortgaged under the Deed of Trust.  At December 31, 201 6 , we had outstanding borrowings under the revolving credit facility totaling $ 789 million with an interest rate of 1. 72 % and outstanding letters of credit totaling $7 million. At December 31, 201 5 , we had outstanding borrowings under the revolving credit facility totaling $840 million with an interest rate of 1.48% and outstanding letters of credit totaling $7 million.  Borrowings under the revolving credit facility bear interest at per annum rates equal to, at our option, (i) LIBOR plus a spread ranging from 1.00% to 1.75% depending on credit ratings assigned to our senior secured non-credit enhanced long-term debt or (ii) an alternate base rate (the highest of (1) the prime rate of JPMorgan Chase, (2) the federal funds effective rate plus 0.50% , and (3) daily one-month LIBOR plus 1.00% ) plus a spread ranging from 0.00% to 0.75% depending on credit ratings assigned to our senior secured non-credit enhanced long-term debt. At December 31, 201 6 , all outstanding borrowings bore interest at LIBOR plus 1.00% . Amounts borrowed under the facility, once repaid, can be bo rrowed again from time to time.  An unused commitment fee is payable quarterly in arrears and upon termination or commitment reduction at a rate equal to 0.100% to 0.275% (such spread depending on certain credit ratings assigned to our senior secured debt) of the daily unused commitments under the revolving credit facility. Letter of credit fees on the stated amount of letters of credit issued under the revolving credit facility are payable to the lenders quarterly in arrears and upon termination at a rate per annum equal to the spread over adjusted LIBOR. Customary fronting and administrative fees are also payable to letter of credit fronting banks. At December 31, 201 6 , letters of credit bore interest at 1.20% , and a commitment fee (at a rate of 0.10% per annum) was payable on the unfunded commitments under the facility, each based on our current credit ratings.  Under the terms of our revolving credit facility, the commitments of the lenders to make loans to us are several and not joint. Accordingly, if any lender fails to make loans to us, our available liquidity could be reduced by an amount up to the aggregate amount of such lender’s commitments under the facility.  Subject to the limitations described below, borrowing capacity available under the credit facility at December 31, 201 6 and 201 5 was $1. 204 billion and $1.153 billion, respectively. Generally, our indentures and revolving credit facility limit the incurrence of other secured indebtedness except for indebtedness secured equally and ratably with the indentures and revolving credit facility and certain permitted exceptions . As described further in Note 7 , the Deed of Trust permits us to secure indebtedness (including borrowings under our revolving credit facility) with the lien of the Deed of Trust . At December 31, 201 6 , the available borrowing capacity of the revolving credit facility could be fully drawn.  The revolving credit facility contains customary covenants for facilities of this type, restricting, subject to certain exceptions, us and our subsidiaries from, among other things: incurring additional liens; entering into mergers and consolidations; and sales of substantial assets. In addition, the revolving credit facility requires that we maintain a consolidated senior debt-to-capitalization ratio of no greater than 0.65 to 1.00 and observe certain customary reporting requirements and other affirmative covenants. For purposes of the ratio, debt is calculated as indebtedness defined in the revolving credit facility (principally, the sum of long-term debt, any capital leases, short-term debt and debt due currently in accordance with GAAP). The debt calculation excludes any transition bonds issued by Bondco, but includes any unamortized fair value discount related to Bondco. Capitalization is calculated as membership interests determined in accordance with GAAP plus indebtedness described above. At December 31, 201 6 , we were in compliance with this covenant with a debt-to-capitalization ratio of 0.4 7 to 1.00 and with all other covenants . 

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2016
Long-Term Debt [Abstract]
LONG-TERM DEBT	7. LONG-TERM DEBT  At December 31, 201 6 and 201 5 , our long-term debt consisted of the following:   December 31,  2016 2015   Oncor (a):  5.000% Fixed Senior Notes due September 30, 2017 $ 324 $ 324  6.800% Fixed Senior Notes due September 1, 2018 550 550  2.150% Fixed Senior Notes due June 1, 2019 250 250  5.750% Fixed Senior Notes due September 30, 2020 126 126  4.100% Fixed Senior Notes due June 1, 2022 400 400  7.000% Fixed Debentures due September 1, 2022 800 800  2.950% Fixed Senior Notes due April 1, 2025 350 350  7.000% Fixed Senior Notes due May 1, 2032 500 500  7.250% Fixed Senior Notes due January 15, 2033 350 350  7.500% Fixed Senior Notes due September 1, 2038 300 300  5.250% Fixed Senior Notes due September 30, 2040 475 475  4.550% Fixed Senior Notes due December 1, 2041 400 400  5.300% Fixed Senior Notes due June 1, 2042 500 500  3.750% Fixed Senior Notes due April 1, 2045 550 375  Unamortized discount and debt issuance costs (36) (54)  Less amount due currently (324) -  Long-term debt, less amounts due currently — Oncor 5,515 5,646   Bondco (b):  5.290% Fixed Series 2004 Bonds due in semiannual installments through May 15, 2016 - 41  Total - 41  Less amount due currently (41)  Long-term debt, less amounts due currently — Bondco - -  Total long-term debt, less amounts due currently $ 5,515 $ 5,646 __________ (a) Secured by first priority lien on certain transmission and distribution assets equally and ratably with all of Oncor’s other secured indebtedness. See “Deed of Trust” below for additional information. (b) The transition bonds were nonrecourse to Oncor and were issued to securitize a regulatory asset.  Debt-Related Activity in 2016  Debt Repayments  Rep ayments of long-term debt in 2016 totaled $41 million, representing the final transition bond principal payment at the scheduled maturity date.  Issuance of Senior Secured Notes  In August 2016, we completed the sale of $175 million aggregate principal amount of 3.75% senior secured notes maturing in April 2045 (Additional 2045 Notes). The Additional 2045 Notes were an additional issuance of our 3.75% senior secured notes maturing in April 2045, $375 million aggregate principal amount of which were previously issued in March 2015 (2045 Notes). The Additional 2045 Notes were issued as part of the same series as the 2045 Notes. We used the net proceeds of approximately $185 million from the sale of the Additional 2045 Notes to repay borrowings under our revolving credit facility and for general corporate purposes. The Additional 2045 Notes and 2045 Notes are secured by the first priority lien and are secured equally and ratably with all of our other secured indebtedness as discussed below. Interest on the Additional 2045 Notes is payable in cash semiannually in arrears on April 1 and October 1 of each year, beginning on October 1, 2016. We may at our option redeem the Additional 2045 Notes, in whole or in part, at any time, at a price equal to 100% of their principal amount, plus accrued and unpaid interest and, until October 1, 2044 , a make-whole premium. The Additional 2045 Notes also contain customary events of default, including failure to pay principal or interest on the notes when due.  The Additional 2045 Notes were issued in a private placement. In January 2017, we completed an offering with the holders of the Additional 2045 Notes to exchange their respective Additional 2045 Notes for notes that have terms identical in all material respects to the Additional 2045 Notes (Exchange Notes), except that the Exchange Notes do not contain terms with respect to transfer restrictions, registration rights and payment of additional interest for failure to observe certain obligations in a certain registration rights agreement. The Exchange Notes were registered on a Form S-4, which was declared effective in December 2016.  Debt-Related Activity in 201 5  Debt Repayments  Rep ayments of long-term debt in 2015 totaled $639 million consisting of $500 million aggregate principal amount of 6.375% senior secured notes paid at the scheduled maturity date of January 15, 2015 and $139 million of transition bond principal payments at scheduled maturity dates.  Issuance of New Senior Secured Notes  In March 2015 , we issued $350 million aggregate principal amount of 2.950% senior secured notes maturing in April 2025 (2025 Notes) and $375 million aggregate principal amount of 3.750% senior secured notes maturing in April 2045 (2045 Notes, and together with the 2025 Notes, the Notes). We used the proceeds (net of the initial purchasers’ discount, fees and expenses) of approximately $714 million from the sale of the Notes to repay borrowings under our revolving credit facility and for other general corporate purposes. The Notes are secured by a first priority lien , and are secured equally and ratably with all of our other secured indebtedness.  Interest on the Notes is payable in cash semiannually in arrears on April 1 and October 1 of each year, beginning on October 1, 2015. Prior to January 1, 2025, in the case of the 2025 Notes, and October 1, 2044, in the case of the 2045 Notes, we may at our option at any time redeem all or part of the Notes at a price equal to 100% of their principal amount, plus accrued and unpaid interest and a make-whole premium. On and after January 1, 2025, in the case of the 2025 Notes, and October 1, 2044, in the case of the 2045 Notes, Oncor may redeem the Notes at any time, in whole or in part, at a redemption price equal to 100% of the principal amount of such Notes, plus accrued and unpaid interest. The Notes also contain customary events of default, including failure to pay principal or interest on the Notes when due.  The Notes were issued in a private placement. In October 2015 we completed an offering with the holders of the Notes to exchange their respective Notes for notes that have terms identical in all material respects to the Notes (Exchange Notes), except that the Exchange Notes do not contain terms with respect to transfer restrictions, registration rights and payment of additional interest for failure to observe certain obligations in a certain registration rights agreement. The Exchange Notes were registered on a Form S-4, which was declared effective in September 2015.  Deed of Trust  Our secured indebtedness, including the revolving credit facility described in Note 6, is secured equally and ratably by a first priority lien on property we acquired or constructed for the transmission and distribution of electricity. The property is mortgaged under the Deed of Trust. The Deed of Trust permits us to secure indebtedness (including borrowings under our revolving credit facility) with the lien of the Deed of Trust up to the aggregate of (i) the amount of available bond credits, and (ii) 85% of the lower of the fair value or cost of certain property additions that could be certified to the Deed of Trust collateral agent. At December 31, 201 6 , the amount of available bond credits was approximately $2.625 billion and the amount of future debt we could secure with property additions, subject to those property additions being certified to the Deed of Trust collateral agent, was $1.739 billion.  Maturities  Long-term debt maturities at December 31, 201 6 , are as follows:   Year Amount  2017 $ 324  2018 550  2019 250  2020 126  2021 -  Thereafter 4,625  Unamortized discount and debt issuance costs (36)  Total $ 5,839  Fair Value of Long-Term Debt  At December 31, 201 6 and 201 5 , the estimated fair value of our long-term debt (including current maturities) totaled $6.751 billion and $6.287 billion, respectively, and the carrying amount totaled $5. 839 billion and $5.687 billion, respectively. The fair value is estimated using observable market data , representing Level 2 valuations under accounting standards related to the determination of fair value.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies [Abstract]
COMMITMENTS AND CONTINGENCIES	8 . COMMITMENTS AND CONTINGENCIES  EFH Bankruptcy Proceedings  On the EFH Petition Date, EFH Corp. and the substantial majority of its direct and indirect subsidiaries that are members of the Texas Holdings Group, including EFIH, EFCH and TCEH, commenced proceedings under Chapter 11 of the U.S. Bankruptcy Code. T he Oncor Ring-Fenced Entities are not parties to the EFH Bankruptcy Proceedings. See Notes 2 and 12 for a discussion of the potential impacts on us as a result of the EFH Bankruptcy Proceedings and our related-party transactions involving members of the Texas Holdings Group, respectively.  Leases  At December 31, 201 6 , our future minimum lease payments under operating leases (with initial or remaining noncancelable lease terms in excess of one year) were as follows:    Year Amount  2017 $ 6  2018 1  2019 1  2020 -  2021 -  Thereafter -  Total future minimum lease payments $ 8  Rent charged to operation and maintenance expense totaled $9 million, $8 million and $ 9 million for the years ended December 31, 201 6 , 201 5 and 201 4 , respectively.  Efficiency Spending  We are required to annually invest in programs designed to improve customer electricity demand efficiencies to satisfy ongoing regulatory requirements. The 201 7 requirement is $49 million which is recoverable in rates . Legal/Regulatory Proceedings  We are involved in various legal and administrative proceedings in the normal course of business, the ultimate resolution of which, in the opinion of management, should not have a material effect upon our financial position, results of operations or cash flows. See Note 3 for additional information regarding contingencies.  Labor Contracts  At December 31, 2016, approximately 19% of our full time employees were represented by a labor union and covered by a collective bargaining agreement with an expiration date of October 25, 2017 .  Environmental Contingencies  We must comply with environmental laws and regulations applicable to the handling and disposal of hazardous waste. We are in compliance with all current laws and regulations; however, the impact, if any, of changes to existing regulations or the implementation of new regulations is not determinable. The costs to comply with environmental regulations can be significantly affected by the following external events or conditions:  · changes to existing state or federal regulation by governmental authorities having jurisdiction over control of toxic substances and hazardous and solid wastes, and other environmental matters, and · the identification of additional sites requiring clean-up or the filing of other complaints in which we may be asserted to be a potential responsible party. 

Membership Interests

Membership Interests	12 Months Ended
	Dec. 31, 2016
Membership Interests [Abstract]
MEMBERSHIP INTERESTS	9 . MEMBERSHIP INTERESTS  Cash Distributions  Distributions are limited by our required regulatory capital structure to be at or below the assumed debt-to-equity ratio established periodically by the PUCT for ratemaking purposes, which is currently set at 60% debt to 40% equity. At December 31, 2016, $103 million was available for distribution to our members as our regulatory capitalization ratio was 59.4% debt and 40.6% equity. The PUCT has the authority to determine what types of debt and equity are included in a utility’s debt-to-equity ratio. For purposes of this ratio, debt is calculated as long-term debt including capital leases plus unamortized gains on reacquired debt less unamortized issuance expenses, premiums and losses on reacquired debt. The debt calculation excludes any transition bonds issued by Bondco. Equity is calculated as membership interests determined in accordance with GAAP, excluding the effects of acquisition accounting (which included recording the initial goodwill and fair value adjustments and subsequent related impairments and amortization).  During 2016, our board of directors declared, and we paid, the following cash distributions to our members:   Declaration Date Payment Date Amount  October 26, 2016 October 27, 2016 $ 41  July 27, 2016 August 11, 2016 $ 68  April 27, 2016 May 11, 2016 $ 65  February 24, 2016 February 25, 2016 $ 56   During 2015, our board of directors declared, and we paid, the following cash distributions to our members:   Declaration Date Payment Date Amount  December 9, 2015 December 11, 2015 $ 18  October 27, 2015 November 9, 2015 $ 135  July 29, 2015 August 10, 2015 $ 118  April 29, 2015 May 15, 2015 $ 65  February 25, 2015 February 26, 2015 $ 100  Accumulated Other Comprehensive Income (Loss)  The following table present s the changes to accumulated other comprehensive income (loss) for the year s ended December 31, 201 6, 2015 and 2014 .   Cash Flow Hedges – Interest Rate Swap Defined Benefit Pension and OPEB Plans Accumulated Other Comprehensive Income (Loss)   Balance at December 31, 2015 $ (22) $ (91) $ (113)  Defined benefit pension plans (net of tax) - - -  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2016 $ (20) $ (91) $ (111)   Balance at December 31, 2014 $ (24) $ (83) $ (107)  Defined benefit pension plans (net of tax) - (8) (8)  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2015 $ (22) $ (91) $ (113)   Balance at December 31, 2013 $ (26) $ (22) $ (48)  Defined benefit pension plans (net of tax) - (61) (61)  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2014 $ (24) $ (83) $ (107) 

Pension and OPEB Plans

Pension and OPEB Plans	12 Months Ended
	Dec. 31, 2016
Pension And OPEB Plans [Abstract]
PENSION AND OPEB PLANS	 10 . PENSION AND OPEB PLANS  Regulatory Recovery of Pension and OPEB Costs  PURA provides for our recovery of pension and OPEB costs applicable to services of our active and retired employees, as well as services of other EFH Corp. active and retired employees prior to the deregulation and disaggregation of EFH Corp.’s electric utility businesses effective January 1, 2002 (recoverable service). Accordingly, we entered into an agreement with EFH Corp. whereby we assumed responsibility for applicable pension and OPEB costs related to those personnel’s recoverable service.  We are authorized to establish a regulatory asset or liability for the difference between the amounts of pension and OPEB costs approved in current billing rates and the actual amounts that would otherwise have been recorded as charges or credits to earnings related to recoverable service. Amounts deferred are ultimately subject to regulatory approval. At December 31, 201 6 and 201 5 , we had recorded regulatory assets totaling $1.199 billion and $ 1.182 b illion, respectively, related to pension and OPEB costs, including amounts related to deferred expenses as well as amounts related to unfunded liabilities that otherwise would be recorded as other comprehensive income.  We have also assumed primary responsibility for pension benefits of a closed group of retired and terminated vested plan participants not related to our regulated utility business (non-recoverable service) in a 2012 transaction. Any retirement costs associated with non-recoverable service is not recoverable through rates.  Pension Plan s  We sponsor the Oncor Retirement Plan and also have liabilities under the Vistra Retirement Plan (formerly EFH Retirement Plan ) , both of which are qualified pension plans under Section 401(a) of the Internal Revenue Code of 1986, as amended (Code), and are subject to the provisions of ERISA. Employees do not contribute to either plan. These pension plans provide benefits to participants under one of two formulas: (i) a Cash Balance Formula under which participants earn monthly contribution credits based on their compensation and a combination of their age and years of service, plus monthly interest credits or (ii) a Traditional Retirement Plan Formula based on years of service and the average earnings of the three years of highest earnings. The interest component of the Cash Balance Formula is variable and is determined using the yield on 30-year Treasury bonds. Under the Cash Balance Formula, future increases in earnings will not apply to prior service costs.  All eligible employees hired after January 1, 2001 participate under the Cash Balance Formula. Certain employees, who, prior to January 1, 2002, participated under the Traditional Retirement Plan Formula, continue their participation under that formula. It is the sponsors’ policy to fund the plans on a current basis to the extent required under existing federal tax and ERISA regulations.  We also have the S upplemental Retirement P lan for certain employees whose retirement benefits cannot be fully earned under the qualified retirement plan, the information for which is included below.  OPEB Plan  Until July 1, 2014, we participated with EFH Corp. and other subsidiaries of EFH Corp. to offer certain health care and life insurance benefits to eligible employees and their eligible dependents upon the retirement of such employees (EFH OPEB Plan). As discussed below, we ceased participation in the EFH OPEB Plan and established our own OPEB plan for our eligible retirees, certain eligible retirees of EFH Corp. for whom we have OPEB liability with respect to their regulated service, and their dependents (Oncor OPEB Plan). For employees retiring on or after January 1, 2002, the retiree contributions required for such coverage vary based on a formula depending on the retiree’s age and years of service.  In April 2014, we entered into an agreement with EFH Corp . (subsequently assigned to Vistra) in which we agreed to transfer to the Oncor OPEB Plan effective July 1, 2014, the assets and liabilities related to our eligible current and future retirees as well as certain eligible retirees of EFH Corp. whose employment included service with both Oncor (or a predecessor regulated electric business) and a non-regulated business of EFH Corp. Pursuant to the agreement, Vistra will retain its portion of the liability for retiree benefits related to those retirees. Since the Oncor OPEB Plan offer ed identical coverages as the EFH OPEB Plan and we and Vistra retain ed the same responsibility for participants as before, there was no financial impact as a result of the transfer other than from a remeasurement of the Oncor OPEB Plan’s asset values and obligations. As we are not responsible for Vistra’s portion of the Oncor OPEB Plan’s unfunded liability totaling $85 million as of December 31, 201 6 , that amount is not reported on our balance sheet.  Pension and OPEB Costs Recognized as Expense  P ension and OPEB amounts p rovided herein include amounts related only to our portion of the various plans based on actuarial computations and reflect our employee and retiree demographics as described above. Our net costs related to pension and OPEB plans for the years ended December 31, 2016, 2015 and 2014 were comprised of the following :      Year Ended December 31,  2016 2015 2014   Pension costs $ 76 $ 104 $ 58  OPEB costs 62 53 48  Total benefit costs 138 157 106  Less amounts recognized principally as property or a regulatory asset (100) (113) (69)  Net amounts recognized as expense $ 38 $ 44 $ 37  T he calculated value method is used to determine the market-related value of the assets held in the trust for purposes of calculating our pension costs. R ealized and unrealized gains or losses in the market-related value of assets are included over a rolling four -year period. Each year, 25% of such gains and losses for the current year and for each of the preceding three years is included in the market-related value. Each year, the market-related value of assets is increased for contributions to the plan and investment income and is decreased for benefit payments and expenses for that year.  T he fair value method is used to determine the market-related value of the assets held in the trust for purposes of calculating OPEB cost.  Detailed Information Regarding Pension and OPEB Benefits  The following pension and OPEB information is based on December 31, 201 6 , 201 5 and 201 4 measurement dates:   Pension Plans OPEB Plan  Year Ended December 31, Year Ended December 31,  2016 2015 2014 2016 2015 2014   Assumptions Used to Determine Net Periodic Pension and OPEB Costs:  Discount rate (a) 4.30% 3.96% 4.74% 4.60% 4.23% 4.98%  Expected return on plan assets 5.54% 5.26% 6.47% 6.30% 6.65% 7.05%  Rate of compensation increase 3.29% 3.29% 3.94% - - -   Components of Net Pension and OPEB Costs:  Service cost $ 23 $ 25 $ 23 $ 7 $ 7 $ 6  Interest cost 134 131 132 49 43 44  Expected return on assets (122) (115) (136) (9) (10) (12)  Amortization of prior service cost (credit) - - - (20) (20) (20)  Amortization of net loss 41 63 39 35 33 30  Net periodic pension and OPEB costs $ 76 $ 104 $ 58 $ 62 $ 53 $ 48   Other Changes in Plan Assets and Benefit Obligations Recognized as Regulatory Assets or in Other Comprehensive Income:  Net loss (gain) $ 41 $ 37 $ 388 $ 10 $ 39 $ 128  Amortization of net loss (41) (63) (39) (35) (33) (30)  Amortization of prior service (cost) credit - - - 20 20 20  Total recognized as regulatory assets or other comprehensive income - (26) 349 (5) 26 118  Total recognized in net periodic pension and OPEB costs and as regulatory assets or other comprehensive income $ 76 $ 78 $ 407 $ 57 $ 79 $ 166 _______________ (a) As a result of the transfer of OPEB plan assets and liabilities from the EFH OPEB Plan to the Oncor OPEB Plan discussed above, the discount rate reflected in OPEB costs for January through June 2014 was 4.98% and for July through December 2014 was 4.39% .   Pension Plans OPEB Plan  Year Ended December 31, Year Ended December 31,  2016 2015 2014 2016 2015 2014   Assumptions Used to Determine Benefit Obligations at Period End:  Discount rate 4.05% 4.30% 3.96% 4.35% 4.60% 4.23%  Rate of compensation increase 3.33% 3.29% 3.29% - - -     Pension Plans OPEB Plan  Year Ended December 31, Year Ended December 31,  2016 2015 2016 2015   Change in Projected Benefit Obligation:  Projected benefit obligation at beginning of year $ 3,201 $ 3,379 $ 1,088 $ 1,054  Service cost 23 25 7 7  Interest cost 134 131 49 43  Participant contributions - - 17 15  Assumption of liabilities - - 7 -  Actuarial (gain) loss 106 (181) 10 25  Benefits paid (157) (153) (62) (56)  Projected benefit obligation at end of year $ 3,307 $ 3,201 $ 1,116 $ 1,088  Accumulated benefit obligation at end of year $ 3,213 $ 3,100 $ - $ -   Change in Plan Assets:  Fair value of assets at beginning of year $ 2,252 $ 2,454 $ 141 $ 161  Actual return (loss) on assets 188 (103) 9 (4)  Employer contributions 4 54 31 25  Assets related to assumed liabilities - - 7 -  Participant contributions - - 17 15  Benefits paid (157) (153) (62) (56)  Fair value of assets at end of year $ 2,287 $ 2,252 $ 143 $ 141   Funded Status:  Projected benefit obligation at end of year $ (3,307) $ (3,201) $ (1,116) $ (1,088)  Fair value of assets at end of year 2,287 2,252 143 141  Funded status at end of year $ (1,020) $ (949) $ (973) $ (947)             Pension Plans OPEB Plan  Year Ended December 31, Year Ended December 31,  2016 2015 2016 2015   Amounts Recognized in the Balance Sheet Consist of:  Liabilities:  Other current liabilities $ (4) $ (4) $ - $ -  Other noncurrent liabilities (1,016) (945) (973) (947)  Net liability recognized $ (1,020) $ (949) $ (973) $ (947)  Regulatory assets:  Net loss $ 583 $ 583 $ 296 $ 320  Prior service cost (credit) - - (30) (50)  Net regulatory asset recognized $ 583 $ 583 $ 266 $ 270  Accumulated other comprehensive net loss $ 136 $ 136 $ 4 $ 4  The following tables provide information regarding the assumed health care cost trend rates.   Year Ended December 31,  2016 2015   Assumed Health Care Cost Trend Rates – Not Medicare Eligible:  Health care cost trend rate assumed for next year 5.80% 6.00%  Rate to which the cost trend is expected to decline (the ultimate trend rate) 5.00% 5.00%  Year that the rate reaches the ultimate trend rate 2024 2024   Assumed Health Care Cost Trend Rates – Medicare Eligible:  Health care cost trend rate assumed for next year 5.70% 5.80%  Rate to which the cost trend is expected to decline (the ultimate trend rate) 5.00% 5.00%  Year that the rate reaches the ultimate trend rate 2024 2024  1-Percentage Point Increase 1-Percentage Point Decrease   Sensitivity Analysis of Assumed Health Care Cost Trend Rates:  Effect on accumulated postretirement obligation $ 152 $ (125)  Effect on postretirement benefits cost 8 (7)  The following table provides information regarding pension plans with projected benefit obligations (PBO) and accumulated benefit obligations (ABO) in excess of the fair value of plan assets.    At December 31,  2016 2015   Pension Plan with PBO and ABO in Excess of Plan Assets:  Projected benefit obligations $ 3,137 $ 3,035  Accumulated benefit obligations 3,051 2,944  Plan assets 2,112 2,085  Pension and OPEB Plan s Investment Strategy and Asset Allocations  Our investment objective for the retirement plans is to invest in a suitable mix of assets to meet the future benefit obligations at an acceptable level of risk, while minimizing the volatility of contributions. Equity securities are held to achieve returns in excess of passive indexes by participating in a wide range of investment opportunities. International equity , real estate securities and credit strategies (high yield bonds, emerging market debt and bank loans) are used to further diversify the equity portfolio . International equity securities may include investments in both developed and emerging international markets. Fixed income securities include primarily corporate bonds from a diversified range of companies, U . S . Treasuries and agency securities and money market instruments. Our investment strategy for fixed income investments is to maintain a high grade portfolio of securities, which assists us in managing the volatility and magnitude of plan contributions and expense while maintaining sufficient cash and short-term investments to pay near-term benefits and expenses. The Oncor Retirement Plan’s investments are managed in two pools: one pool associated with the recoverable service portion of plan obligations related to Oncor’s regulated utility business, and a second pool associated with the non-recoverable service portion of plan obligations not related to Oncor’s regulated utility business. Each pool is invested in a broadly diversified portfolio as shown below. The second pool represents about 34% of total investments at December 31, 2016.  The target asset allocation ranges of the pension plan s investments by asset category are as follows:   Target Allocation Ranges  Asset Category Recoverable Nonrecoverable   International equities 14% - 18% 5% - 9%  U.S. equities 17% - 21% 6% - 10%  Real estate 4% - 5% -  Credit strategies 6% - 8% 4% - 6%  Fixed income 48% - 60% 76% - 84%  Our investment objective for the OPEB p lan primarily follows the objectives of the pension plans discussed above, while maintaining sufficient cash and short-term investments to pay near-term benefits and expenses. The actual amounts at December 31, 201 6 provided below are consistent with the asset allocation targets.  Fair Value Measurement of Pension Plan s Assets  At December 31, 201 6 and 201 5 , pension plan s assets measured at fair value on a recurring basis consisted of the following:   At December 31, 2016  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ - $ 14 $ - $ 14  Equity securities:  U.S. 193 3 - 196  International 225 - - 225  Fixed income securities:  Corporate bonds (a) - 1,089 - 1,089  U.S. Treasuries - 223 - 223  Other (b) - 40 - 40  Real estate - - 5 5  Total assets in the fair value hierarchy $ 418 $ 1,369 $ 5 1,792  Total assets measured at net asset value (c) 495  Total fair value of plan assets $ 2,287   At December 31, 2015 (d)  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ - $ 21 $ - $ 21  Equity securities:  U.S. 201 8 - 209  International 255 1 - 256  Fixed income securities:  Corporate bonds (a) - 1,098 - 1,098  U.S. Treasuries - 189 - 189  Other (b) - 46 - 46  Real estate - - 5 5  Total assets in the fair value hierarchy $ 456 $ 1,363 $ 5 $ 1,824  Total assets measured at net asset value (c) 428  Total fair value of plan assets $ 2,252 _____________ (a) Substantially all corporate bonds are rated investment grade by a major ratings agency such as Moody’s. (b) Other consists primarily of municipal bonds, emerging market debt, bank loans and fixed income derivative instruments. (c) Fair value was measured using the net asset value (NAV) per share as a practical expedient as the investments did not have a readily determinable fair value and are not required to be classified in the fair value hierarchy. The NAV fair value amounts presented here are intended to permit a reconciliation to the total fair value of plan assets. (d) 2015 presentation has been revised to reflect the application of ASU 2015-07 consistent with 2016 (see Note 1).  There was no significant change in the fair value of Level 3 assets in the periods presented.  Fair Value Measurement of OPEB P lan Assets  At December 31, 201 6 and 201 5, OPEB p lan assets measured at fair value on a recurring basis consisted of the following:   At December 31, 2016  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ 2 $ - $ - $ 2  Equity securities:  U.S. 41 - - 41  International 28 - - 28  Fixed income securities:  Corporate bonds (a) - 28 - 28  U.S. Treasuries - 2 - 2  Other (b) 28 - - 28  Total assets in the fair value hierarchy $ 99 $ 30 $ - 129  Total assets measured at net asset value (c) 14  Total fair value of plan assets $ 143   At December 31, 2015 (d)  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ 4 $ 1 $ - $ 5  Equity securities:  U.S. 39 - - 39  International 25 - - 25  Fixed income securities:  Corporate bonds (a) - 29 - 29  U.S. Treasuries - 1 - 1  Other (b) 35 1 - 36  Total assets in the fair value hierarchy $ 103 $ 32 $ - 135  Total assets measured at net asset value (c) 6  Total fair value of plan assets $ 141 _____________ (a) Substantially all corporate bonds are rated investment grade by a major ratings agency such as Moody’s. (b) Other consists primarily of diversified bond mutual funds. (c) Fair value was measured using the net asset value (NAV) per share as a practical expedient as the investments did not have a readily determinable fair value and are not required to be classified in the fair value hierarchy. The NAV fair value amounts presented here are intended to permit a reconciliation to the total fair value of plan assets. (d) 2015 presentation has been revised to reflect the application of ASU 2015-07 consistent with 2016 (see Note 1).   Expected Long-Term Rate of Return on Assets Assumption  The retirement plans’ strategic asset allocation is determined in conjunction with the plans’ advisors and utilizes a comprehensive Asset-Liability modeling approach to evaluate potential long-term outcomes of various investment strategies. The modeling incorporates long-term rate of return assumptions for each asset class based on historical and future expected asset class returns, current market conditions, rate of inflation, current prospects for economic growth, and taking into account the diversification benefits of investing in multiple asset classes and potential benefits of employing active investment management.   Pension Plans OPEB Plan  Asset Class Expected Long-Term Rate of Return Asset Class Expected Long-Term Rate of Return   International equity securities 6.98% 401(h) accounts 6.60%  U.S. equity securities 6.40% Life insurance VEBA 6.01%  Real estate 5.00% Union VEBA 6.01%  Credit strategies 5.22% Non-union VEBA 2.20%  Fixed income securities 4.50% Weighted average 6.10%  Weighted average (a) 5.46% _____________ (a) The 2017 expected long-term rate of return for the nonregulated portion of the Oncor Retirement Plan is 4.62% and 5.13% for Oncor's portion of the Vistra Retirement Plan.  Significant Concentrations of Risk  The plans’ investments are exposed to risks such as interest rate, capital market and credit risks. We seek to optimize return on investment consistent with levels of liquidity and investment risk which are prudent and reasonable, given prevailing capital market conditions and other factors specific to participating employers. While we recognize the importance of return, investments will be diversified in order to minimize the risk of large losses unless, under the circumstances, it is clearly prudent not to do so. There are also various restrictions and guidelines in place including limitations on types of investments allowed and portfolio weightings for certain investment securities to assist in the mitigation of the risk of large losses.  Assumed Discount Rate  For the Oncor retirement plans at December 31, 201 6 , we selected the assumed discount rate using the Aon Hewitt AA-AAA Bond Universe yield curve, which is based on corporate bond yields and at December 31, 201 6 consisted of 1,217 corporate bonds with an average rating of AA and AAA using Moody’s, S&P and Fitch ratings. For the Oncor OPEB Plan at December 31, 2016, we selected the assumed discount rate using the Aon Hewitt AA Above Median yield curve, which is based on corporate bond yields and at December 31, 201 6 consisted of 489 corporate bonds with an average rating of AA using Moody’s, S&P and Fitch ratings.  Amortization in 201 7  In 201 7 , amortization of the net actuarial loss and prior service c redit for the defined benefit pension plans from regulatory assets and other comprehensive income into net periodic benefit cost is expected to be $46 million and zero , respectively. Amortization of the net actuarial loss and prior service credit for the OPEB plan from regulatory assets into net periodic benefit cost is expected to be $32 million and a $20 million credit, respectively.  Pension and OPEB Plan s Cash Contributions  Our contributions to the benefit plans were as follows:   Year Ended December 31,  2016 2015 2014   Pension plans contributions $ 4 $ 54 $ 68  OPEB plan contributions 31 25 18  Total contributions $ 35 $ 79 $ 86  Our funding for the pension plans and the Oncor OPEB P lan is expected to total $149 million and $31 million, respectively in 201 7 and approximately $586 million and $153 million, respectively, in the 201 7 to 20 21 period.  Future Benefit Payments  Estimated future benefit payments to participants are as follows:   2017 2018 2019 2020 2021 2022-26   Pension plans $ 173 $ 179 $ 184 $ 190 $ 195 $ 1,032  OPEB plan $ 52 $ 55 $ 57 $ 60 $ 63 $ 338  Thrift Plan  Our employees are eligible to participate in a qualified savings plan, a participant-directed defined contribution plan intended to qualify under Section 401(a) of the Code, and is subject to the provisions of ERISA. Under the p lan, employees may contribute, through pre-tax salary deferrals and/or after-tax applicable payroll deductions, a portion of t heir regular salary or wages as permitted under law. Employer matching contributions are made in an amount equal to 100% of the first 6% of employee contributions for employees who are covered under the Cash Balance Formula of the Oncor Retirement Plan, and 75% of the first 6% of employee contributions for employees who are covered under the Traditional Retirement Plan Formula of the Oncor Retirement Plan. Employer matching contributions are made in cash and may be allocated by participants to any of the plan's investment options.  Until December 31, 2014, the thrift plan in which our eligible employees were able to participate was sponsored by EFH Corp. (EFH Thrift Plan). Our contribution to the EFH Thrift Plan totaled $13 million for the y ear ended December 31, 2014. Effective January 1, 2015, the accounts of Oncor participants were transferred from the EFH Thrift Plan to an Oncor-sponsored spin-off of the EFH Thrift Plan (Oncor Thrift Plan). Our contributions to the Oncor Thrift Plan totaled $15 million and $14 million for the year ended December 31, 2016 and 201 5, respectively. Our matching contributions are the same under the Oncor Thrift Plan as they were under the EFH Thrift Plan at the time of the transfer. Since the Oncor Thrift Plan offers identical benefits to our employees, transfer to the Oncor Thrift Plan did not have an impact on our results of operations, financial condition or cash flows.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2016
Stock-Based Compensation [Abstract]
STOCK-BASED COMPENSATION	11. STOCK-BASED COMPENSATION  We currently do not offer stock-based compensation to our employees or directors. In 2008, we established the SARs Plan under which certain of our executive officers and key employees were granted stock appreciation rights payable in cash, or in some circumstances, Oncor membership interests. In February 2009, we established the Oncor Electric Delivery Company LLC Director Stock Appreciation Rights Plan (the Director SARs Plan) under which certain non-employee members of our board of directors and other persons having a relationship with us were granted SARs payable in cash, or in some circumstances, Oncor membership interests.  In November 2012, we accepted the early exercise of all outstanding SARs (both vested and unvested ) issued to date pursuant to both SARs Plans. As part of the 2012 early exercise of SARs we began accruing interest on dividends declared with respect to the SARs. Under both SARs plans, dividends that were paid in respect of Oncor membership interests while the SARs were outstanding were credited to the SARs holder’s account as if the SARs were units, payable upon the earliest to occur of death, disability, separation from service, unforeseeable emergency, a change in control, or the occurrence of an event triggering SAR exercisability pursuant to Section 5(c)(ii) of the SARs Plan . As a result, at December 31, 2016, we have recorded a liability of approximately $11 million relating to SARS dividend accruals. For accounting purposes, the liability is discounted based on an employee’s or director’s expected retirement date . We recognized approximately $1 million in accretion and interest with respect to such dividends in each of the years 201 6 , 201 5 and 201 4. 

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2016
Related-Party Transactions [Abstract]
RELATED-PARTY TRANSACTIONS	1 2 . RELATED-PARTY TRANSACTIONS  The following represent our significant related-party transactions and related matters . See Note 2 for additional information regarding related-party contingencies resulting from the EFH Bankruptcy Proceedings and information regarding the Vistra Spin-Off. As a result of the Vistra Spin-Off, Vistra and its subsidiaries, including Luminant and TXU Energy, ceased to be related parties as of October 3, 2016.  · We recorded revenue from TCEH, principally for electricity delivery fees, which totaled $715 million for the period January 1, 2016 through October 2, 2016 and $955 million and $971 million for the years ended December 31, 2015 and 2014, respectively. The fees are based on rates regulated by the PUCT that apply to all REPs.  Trade accounts and other receivables from EFH Corp. affiliates – net reported on our balance sheet , primarily consisting of trade receivables from TCEH related to these electricity delivery fees , are as follows:    At December 31,  2015   Trade accounts and other receivables from affiliates $ 120  Trade accounts and other payables to affiliates (2)  Trade accounts and other receivables from affiliates – net $ 118  Trade accou nts and other receivables from affiliates at December 31, 2016 was zero as a result of the Vistra Spin-Off.    · EFH Corp. subsidiaries charge us for certain administrative services at cost. Our payments to EFH Corp. subsidiaries for administrative services, which are primarily reported in operation and maintenance expenses, totaled $1 million, $17 million and $ 32 million for the years ended December 31, 201 6 , 201 5 and 201 4 , respectively. We also charge each other for shared facilities at cost. Our payments to EFH Corp. subsidiaries for shared facilities totaled $3 million for the year ended December 31, 2016 and $4 million for each of the years ended December 31, 201 5 and 201 4 , respectively. Payments we received from EFH Corp. subsidiaries related to shared facilities, totaled $1 million for the year ended December 31, 2016 and $2 million for each of the years ended December 31, 201 5 and 201 4 .  · Through June 30, 2014, we participated in the Energy Future Holdings Health and Welfare Benefit Program, which provided employee benefits to our workforce. In October 2013, we notified EFH Corp. of our intention to withdraw from the benefit program effective June 30, 2014 and entered into an agreement with EFH Corp. pursuant to which we paid EFH Corp. $1 million in June 2014 to reimburse EFH Corp. for its increased costs under the program as a result of our withdrawal from the program and the additional administrative work required to effectuate our withdrawal from the benefit program and transition to the new benefit program. In April 2014, we entered into a welfare benefit administration agreement with EFH Corp., pursuant to which EFH Corp. continued to provide us with welfare benefit administration services under our new benefit plans from July 1, 2014 until December 31, 2014. These amounts are included in the administrative services payments to EFH Corp. subsidiaries reported above.  · We are not a member of EFH Corp.’s consolidated tax group, but EFH Corp.’s consolidated federal income tax return includes EFH Corp.’s portion of our results due to EFH Corp.’s equity ownership in us. Under the terms of a tax sharing agreement among us, Oncor Holdings, Texas Transmission, Investment LLC and EFH Corp., we are generally obligated to make payments to Texas Transmission, Investment LLC and EFH Corp., pro rata in accordance with their respective membership interests, in an aggregate amount that is substantially equal to the amount of federal income taxes that we would have been required to pay if we were filing our own corporate income tax return. For periods prior to the tax sharing agreement (entered into in October 2007 and amended and restated in November 2008), we are responsible for our share of redetermined tax liability for the EFH Corp. consolidated tax group. EFH Corp. also includes our results in its consolidated Texas margin tax payments, which we account for as income taxes and calculate as if we were filing our own return. See discussion in Note 1 under “ Provision in Lieu of Income Taxes.” Under the “in lieu of” tax concept, all in lieu of tax assets and tax liabilities represent amounts that will eventually be settled with our members. In the event such amounts are not paid under the tax sharing agreement, it is probable that this regulatory liability will continue to be included in Oncor’s rate setting processes .  Amounts payable to (receivable from) members related to income taxes under the agreement and reported on our balance sheet consisted of the following:    At December 31, 2016 At December 31, 2015  EFH Corp. Texas Transmission Total EFH Corp. Texas Transmission Total   Federal income taxes receivable $ (62) $ (18) $ (80) $ (109) $ (27) $ (136)  Texas margin taxes payable 20 - 20 20 - 20  Net payable (receivable) $ (42) $ (18) $ (60) $ (89) $ (27) $ (116)  Cash payments made to (received from) members related to income taxes consisted of the following:     Year Ended December 31, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014  EFH Corp. Texas Transm. Total EFH Corp. Texas Transm. Total EFH Corp. Texas Transm. Total   Federal income taxes $ - $ - $ - $ 108 $ 27 $ 135 $ 215 $ 54 $ 269  Texas margin taxes 20 - 20 24 - 24 22 - 22  Total payments (receipts) $ 20 $ - $ 20 $ 132 $ 27 $ 159 $ 237 $ 54 $ 291 ______________  · Our PUCT-approved tariffs include requirements to assure adequate credit worthiness of any REP to support the REP’s obligation to collect transition bond-related charges on behalf of Bondco. Under these tariffs, as a result of TCEH’s credit rating being below investment grade, TCEH was required to post collateral support in an amount equal to estimated transition charges over specified time periods. Accordingly, at December 31, 201 5 , TCEH had posted letters of credit in the amount of $6 million for our benefit. No letters of credit were posted at December 31, 2016 since the transition bonds were paid in full in May 2016.  · Related parties of the Sponsor Group have (1) sold, acquired or participated in the offerings of our debt or debt securities in open market transactions or through loan syndications, and (2) performed various financial advisory, dealer, commercial banking and investment banking services for us and certain of our affiliates for which they have received or will receive customary fees and expenses, and may from time to time in the future participate in any of the items in (1) and (2) above. Also, as of March 2015, 16.6% of the equity in an existing vendor of the company was acquired by a member of the Sponsor Group . During 2016 and 2015, this vendor performed transmission and distribution system construction and maintenance services for us. Cash payments were made for such services to this vendor totaling $188 million for 2016 , of which approximately $180 million was capitalized and $8 million recorded as an operation and maintenance expense, and $128 million for the period April through December 2015, of which approximately $121 million was capitalized and $7 million recorded as an operation and maintenance expense. At December 31, 2016 and 2015, we had outstanding trade payables to this vendor of $5 million and $3 million, respectively.  See Notes 1, 4 , 9 and 10 for information regarding the tax sharing agreement, distributions to members and our participation in previous EFH Corp. pension and OPEB plans.

Supplementary Financial Informa

Supplementary Financial Information	12 Months Ended
	Dec. 31, 2016
Supplementary Financial Information [Abstract]
SUPPLEMENTARY FINANCIAL INFORMATION	13 . SUPPLEMENTARY FINANCIAL INFORMATION  Variable Interest Entities  Through December 29, 2016, we were the primary beneficiary and consolidated a former wholly-owned VIE, Bondco, which was organized for the limited purpose of issuing specific transition bonds and purchasing and owning transition property acquired from us that was pledged as collateral to secure the bonds. We acted as the servicer for this entity to collect transition charges authorized by the PUCT. These funds were remitted to the trustee and used for interest and principal payments on the transition bonds and related costs. Bondco was dissolved effective December 29, 2016.  Bondco had issued an aggregate $1.3 billion principal amount of transition bonds during 2003 and 2004. The 2003 Series transition bonds matured and were paid in full in 2015 and the 2004 Series transition bonds matured and were paid in full in May 2016.  The material assets and liabilities of Bondco are presented separately on the face of our Consolidated Balance Sheet because the assets were restricted and could only be used to settle the obligations of Bondco, and Bondco’s creditors did not have recourse to our general credit or assets. We did not provide any financial support to Bondco during the years ended Decemb er 31, 2016 and 2015.  Major Customers  Revenues from subsidiaries of Vistra (formerly subsidiaries of TCEH) represented 23% , 25 % and 25 % of our total operating revenues for the years ended December 31, 2016, 2015 and 2014, respectively. Revenues from REP subsidiaries of a nother nonaffiliated entity, collectively represented 17% , 17% and 16% of total operating revenues for each of the years ended December 31, 2016, 2015 and 2014, respectively. No other customer represented 10 % or more of our total operating revenues.  Other Income and Deductions  Year Ended December 31,  2016 2015 2014   Accretion of fair value adjustment (discount) to regulatory assets due to acquisition accounting $ 1 $ 5 $ 12  Professional fees (15) (19) (14)  Non-recoverable pension and OPEB (Note 9) (2) (9) (1)  Interest income 2 - 3  Other (1) 1 1  Total other income and (deductions) - net $ (15) $ (22) $ 1  Interest Expense and Related Charges   Year Ended December 31,  2016 2015 2014   Interest $ 341 $ 335 $ 355  Amortization of debt issuance costs and discounts 3 3 3  Less allowance for funds used during construction – capitalized interest portion (8) (5) (5)  Total interest expense and related charges $ 336 $ 333 $ 353  Restricted Cash  Restricted cash amounts reported on our balance sheet consisted of the following:   At December 31, 2015  Current Assets   Customer collections related to transition bonds used only to service debt and pay expenses $ 22  Reserve for fees associated with transition bonds 10  Reserve for shortfalls of transition bond charges 6  Total restricted cash $ 38  Restricted cash at December 31, 2016 was zero as a result of the maturity and payment in full of the 2004 Series transition bonds in May 2016.  Trade Accounts and Other Receivable s  Trade a ccounts and other r eceivable s reported on our balance sheet consisted of the following:   At December 31,  2016 2015   Gross trade accounts and other receivables $ 548 $ 509  Trade accounts and other receivables from TCEH (affiliated) - (118)  Allowance for uncollectible accounts (3) (3)  Trade accounts receivable from nonaffiliates – net $ 545 $ 388  At December 31, 201 6 , REP subsidiaries of Vistra collectively represented approximately 15% of the nonaffiliated trade accounts receivable amount. Also, at D ecember 31, 201 6 and 201 5 , REP subsidiaries of another nonaffiliated entity collectively represented approximately 12% and 13% , respectively, of the nonaffiliated trade accounts receivable amount.  Under a PUCT rule relating to the Certification of Retail Electric Providers, write-offs of uncollectible amounts owed by nonaffiliated REPs are deferred as a regulatory asset.  Investments and Other Property  Investments and other property reported on our balance sheet as part of property, plant and equipment consisted of the following:   At December 31,  2016 2015   Assets related to employee benefit plans, including employee savings programs $ 98 $ 94  Land 2 3  Total investments and other property $ 100 $ 97  The majority of these assets represent cash surrender values of life insurance policies that are purchased to fund liabilities under deferred compensation plans. At December 31, 201 6 and 201 5 , the face amount of these policies totaled $153 million and $155 million, respectively, and the net cash surrender values (determined using a Level 2 valuation technique) totaled $76 million for each of the years ended December 31, 2016 and 2015. Changes in cash surrender value are netted against premiums paid. Other investment assets held to satisfy deferred compensation liabilities are recorded at market value.  Property, Plant and Equipment  Property, plant and equipment reported on our balance sheet consisted of the following:    Composite Depreciation Rate/ At December 31,  Avg. Life at December 31, 2016 2016 2015  Assets in service:  Distribution 3.9% / 25.5 years $ 11,369 $ 10,861  Transmission 2.8% / 35.2 years 7,734 7,209  Other assets 9.0% / 11.1 years 1,131 1,002  Total 20,234 19,072  Less accumulated depreciation 6,836 6,479  Net of accumulated depreciation 13,398 12,593  Construction work in progress 416 416  Held for future use 15 15  Property, plant and equipment – net $ 13,829 $ 13,024  Depreciation expense as a percent of average depreciable property approximated 3.5% , 3.6% and 3.6% for the years ended December 31, 2016, 2015 and 2014, respectively.  Intangible Assets  Intangible assets (other than goodwill) reported on our balance sheet consisted of the following:   At December 31, 2016 At December 31, 2015  Gross Gross  Carrying Accumulated Carrying Accumulated  Amount Amortization Net Amount Amortization Net  Identifiable intangible assets subject to amortization included in property, plant and equipment:  Land easements $ 491 $ 94 $ 397 $ 467 $ 91 $ 376  Capitalized software 470 326 144 435 269 166  Total $ 961 $ 420 $ 541 $ 902 $ 360 $ 542  A ggregate amortization expense for intangible assets totaled $61 million , $64 million and $58 million for each of the years ended December 31, 201 6 , 201 5 and 201 4, respectively . At December 31, 201 6 , the weighted average remaining useful lives of capitalized land easements and software were 84 years and 3 years, respectively. The estimated aggregate amortization expense for each of the next five fiscal years is as follows:   Year Amortization Expense   2017 $ 56  2018 50  2019 47  2020 46  2021 46 At both December 31, 201 6 and 201 5 , goodwill totaling $ 4.1 billion was reported on our balance sheet. None of this goodwill is being deducted for tax purposes. See Note 1 regarding goodwill impairment assessment and testing.  Employee Benefit Obligations and Other  Employee benefit obligations and other reported on our balance sheet consisted of the following:   At December 31,  2016 2015   Retirement plans and other employee benefits $ 2,092 $ 1,985  Uncertain tax positions (including accrued interest) 3 3  Amount payable related to income taxes - -  Investment tax credits 12 15  Other 61 60  Total other noncurrent liabilities and deferred credits $ 2,168 $ 2,063  Supplemental Cash Flow Information   Year Ended December 31,  2016 2015 2014   Cash payments related to:  Interest $ 336 $ 346 $ 356  Less capitalized interest (8) (5) (5)  Interest payments (net of amounts capitalized) $ 328 $ 341 $ 351  Amount in lieu of income taxes:  Federal $ - $ 135 $ 269  State 20 43 22  Total amount in lieu of income taxes $ 20 $ 178 $ 291  Noncash construction expenditures (a) $ 122 $ 56 $ 82 ______________ (a) Represents end-of-period accruals.  Quarterly Information (unaudited)  Results of operations by quarter for the years ended December 31, 2016 and 2015 are summarized below. In our opinion, all adjustments (consisting of normal recurring accruals) necessary for a fair statement of such amounts have been made. Quarterly results are not necessarily indicative of a full year’s operations because of seasonal and other factors.   2016 First Quarter Second Quarter Third Quarter Fourth Quarter   Operating revenues $ 943 $ 948 $ 1,071 $ 958  Operating income 169 196 250 162  Net income 81 110 163 77   2015 First Quarter Second Quarter Third Quarter Fourth Quarter   Operating revenues $ 946 $ 938 $ 1,072 $ 922  Operating income 180 186 253 160  Net income 98 98 163 73 

Description Of Business and S23

Description Of Business and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Description Of Business And Significant Accounting Policies [Abstract]
Description Of Business	Description of Business  References in this report to “we,” “our,” “us” and “the company” are to Oncor and/or its subsidiary as apparent in the context. See “Glossary” for definition of terms and abbreviations.  We are a regulated electricity transmission and distribution company principally engaged in providing delivery services to REPs that sell power in the north-central, eastern and western parts of Texas. Revenues from subsidiaries of Vistra (formerly subsidiaries of TCEH) represented 23% , 25% and 25% of our total operating revenues for the years ended December 31, 2016, 2015 and 2014, respectively. We are a direct, majority-owned subsidiary of Oncor Holdings, which is a direct, wholly-owned subsidiary of EFIH, a direct, wholly-owned subsidiary of EFH Corp. EFH Corp. is a subsidiary of Texas Holdings, which is controlled by the Sponsor Group. Oncor Holdings owns 80.03% of our membership interests, Texas Transmission owns 19.75% of our membership interests and certain members of our management team and board of directors indirectly own the remaining membership interests through Investment LLC. We are managed as an integrated business; consequently, there are no separate reportable business segments.  Our consolidated financial statements include our former wholly-owned, bankruptcy-remote financing subsidiary, Bondco, a VIE through December 29, 2016, at which time it was dissolved (see Note 13) . This financing subsidiary was organized for the limited purpose of issuing certain transition bonds to recover generation-related regulatory asset stranded costs and other qualified costs under an order issued by the PUCT in 2002. Bondco issued an aggregate $1.3 billion principal amount of transition bonds during 2003 and 2004. The 2003 Series transition bonds matured and were paid in full in 2015 and the 2004 Series transition bonds matured and were paid in full in May 2016. Final true-up proceedings and refunds of over-collected transition charges for the transition bonds were conducted by Oncor and the PUCT during 2016 and had no material net income impact.  Various “ring-fencing” measures have been taken to enhance the separateness between the Oncor Ring-Fenced Entities and the Texas Holdings Group and our credit quality. These measures serve to mitigate our and Oncor Holdings’ credit exposure to the Texas Holdings Group and to reduce the risk that our assets and liabilities or those of Oncor Holdings would be substantively consolidated with the assets and liabilities of the Texas Holdings Group in connection with a bankruptcy of one or more of those entities, including the EFH Bankruptcy Proceedings discussed below. Such measures include, among other things: our sale of a 19.75% equity interest to Texas Transmission in November 2008; maintenance of separate books and records for the Oncor Ring-Fenced Entities; our board of directors being comprised of a majority of independent directors; and prohibitions on the Oncor Ring-Fenced Entities providing credit support to, or receiving credit support from, any member of the Texas Holdings Group. The assets and liabilities of the Oncor Ring-Fenced Entities are separate and distinct from those of the Texas Holdings Group. None of the assets of the Oncor Ring-Fenced Entities are available to satisfy the debt or contractual obligations of any member of the Texas Holdings Group. We do no t bear any liability for debt or contractual obligations of the Texas Holdings Group, and vice versa. Accordingly, our operations are conducted, and our cash flows are managed, independently from the Texas Holdings Group.
EFH Bankruptcy Proceedings	EFH Bankruptcy Proceedings  On the EFH Petition Date, EFH Corp. and the substantial majority of its direct and indirect subsidiaries at the time, including EFIH, EFCH and TCEH, commenced proceedings under Chapter 11 of the U.S. Bankruptcy Code. The Oncor Ring-Fenced Entities are not parties to the EFH Bankruptcy Proceedings. We believe the “ring-fencing” measures discussed above mitigate our potential exposure to the EFH Bankruptcy Proceedings. See Note 2 for a discussion of the potential impacts of the EFH Bankruptcy Proceedings on our financial statements.
Basis Of Presentation	Basis of Presentation  Our consolidated financial statements have been prepared in accordance with GAAP. All dollar amounts in the financial statements and tables in the notes are stated in millions of U.S. dollars unless otherwise indicated.
Use Of Estimates	Use of Estimates  Preparation of our financial statements requires management to make estimates and assumptions about future events that affect the reporting of assets and liabilities at the balance sheet dates and the reported amounts of revenue and expense, including fair value measurements. In the event estimates and/or assumptions prove to be different from actual amounts, adjustments are made in subsequent periods to reflect more current information. No material adjustments were made to previous estimates or assumptions during the current year.
Revenue Recognition	Revenue Recognition  General  Oncor’s revenu e is billed under tariffs approved by the PUCT and the majority of revenues are related to providing electric delivery service to consumers. Tariff rates are designed to recover the cost of providing electric delivery service including a reasonable rate of return on invested capital. Revenues are generally recognized when the underlying service has been provided in an amount prescribed by the related tariff.  Reconcilable Tariffs  The PUCT has designated certain tariffs (TCRF, EECRF surcharges, AMS surcharges and charges related to transition bonds) as reconcilable, which means the differences between amounts billed under these tariffs and the related incurred costs are deferred as either regulatory assets or regulatory liabilities. Accordingly, at prescribed intervals, future tariffs are adjusted to either repay regulatory liabilities or collect regulatory assets. See “Regulatory Assets and Liabilities” below.
Impairment Of Long-Lived Assets And Goodwill	Impairment of Long-Lived Assets and Goodwill  We evaluate long-lived assets (including intangible assets with finite lives) for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable.  We also evaluate goodwill for impairment annually (at December 1) and whenever events or changes in circumstances indicate that an impairment may exist. The determination of the existence of these and other indications of impairment involves judgments that are subjective in nature and may require the use of estimates in forecasting future results and cash flows.  If at the assessment date our carrying value exceeds our estimated fair value (enterprise value), then the estimated enterprise value is compared to the estimated fair values of our operating assets (including identifiable intangible assets) and liabilities at the assessment date. The resultant implied goodwill amount is compared to the recorded goodwill amount. Any excess of the recorded goodwill amount over the implied goodwill amount is written off as an impairment charge.  The goodwill impairment tests performed in 2016, 2015 and 2014 were based on a qualitative assessment in which we considered macroeconomic conditions, industry and market considerations, cost factors, overall financial performance and other relative factors . Based on tests results, no impairments were recognized in 2016, 2015 or 2014 .
Provision In Lieu Of Income Taxes	Provision in Lieu of Income Taxes  Effective with the November 2008 sale of equity interests to Texas Transmission and Investment LLC, we became a partnership for U.S. federal income tax purposes, and subsequently we are not a member of EFH Corp.’s consolidated tax group and only EFH Corp.’s share of our partnership income is included in its consolidated federal income tax return. Our tax sharing agreement with Oncor Holdings and EFH Corp. was amended in November 2008 to include Texas Transmission and Investment LLC. The tax sharing agreement provides for the calculation of tax liability substantially as if we and Oncor Holdings were taxed as corporations, and requires tax payments to members determined on that basis (without duplication for any income taxes paid by a subsidiary of Oncor Holdings).  While partnerships are not subject to income taxes, in consideration of the tax sharing agreement and the presentation of our financial statements as an entity subject to cost-based regulatory rate-setting processes, with such costs including income taxes, the financial statements present amounts determined under the tax sharing agreement as “provision in lieu of income taxes” and “liability in lieu of deferred income taxes” for periods subsequent to the sales of equity interests discussed in Note 4. Such amounts are determined in accordance with the provisions of accounting guidance for income taxes and for uncertainty in income taxes and thus differences between the book and tax bases of assets and liabilities are accounted for as if we were taxed as a corporation. The accounting guidance for rate-regulated enterprises requires the recognition of regulatory assets or liabilities if it is probable such deferred tax amounts will be recovered from, or returned to customers in future rates. Investment tax credits are amortized to income over the estimated lives of the related properties.  We classify interest and penalties expense related to uncertain tax positions as current provision in lieu of income taxes as discussed in Note 4.
Defined Benefit Pension Plans And OPEB Plans	Defined Benefit Pension Plans and OPEB Plans  We have liabilities under pension plans that offer benefits based on either a traditional defined benefit formula or a cash balance formula and an OPEB plan that offers certain health care and life insurance benefits to eligible employees and their eligible dependents upon the retirement of such employees from the company. Costs of pension and OPEB plans are dependent upon numerous factors, assumptions and estimates. See Note 10 for additional information regarding pension and OPEB plans.
Contingencies	Contingencies  We evaluate and account for contingencies using the best information available. A loss contingency is accrued and disclosed when it is probable that an asset has been impaired or a liability incurred and the amount of the loss can be reasonably estimated. If a range of probable loss is established, the minimum amount in the range is accrued, unless some other amount within the range appears to be a better estimate. If the probable loss cannot be reasonably estimated, no accrual is recorded, but the loss contingency is disclosed to the effect that the probable loss cannot be reasonably estimated. A loss contingency will be disclosed when it is reasonably possible that an asset has been impaired or a liability incurred. If the likelihood that an impairment or incurrence is remote, the contingency is neither accrued nor disclosed. Gain contingencies are recognized upon realization.
System Of Accounts	System of Accounts  Our accounting records have been maintained in accordance with the FERC Uniform System of Accounts as adopted by the PUCT.
Property, Plant And Equipment	Property, Plant and Equipment  Properties are stated at original cost. The cost of self-constructed property additions includes materials and both direct and indirect labor and applicable overhead and an allowance for funds used during construction.  D epreciation of property, plant and equipment is calculated on a straight-line basis over the estimated service lives of the properties based on depreciation rates approved by the PUCT. As is common in the industry, depreciation expense is recorded using composite depreciation rates that reflect blended estimates of the lives of major asset groups as compared to depreciation expense calculated on a component asset-by-asset basis. Depreciation rates include plant removal costs as a component of depreciation expense, consistent with regulatory treatment. Actual removal costs incurred are charged to accumulated depreciation. When accrued removal costs exceed incurred removal costs, the difference is reclassified as a regulatory liability to retire assets in the future.
Regulatory Assets And Liabilities	Regulatory Assets and Liabilities  Our financial statements reflect regulatory assets and liabilities under cost-based rate regulation in accordance with accounting standards related to the effect of certain types of regulation. Regulatory decisions can have an impact on the recovery of costs, the rate earned on invested capital and the timing and amount of assets to be recovered by rates. See Note 5 for details of regulatory assets and liabilities.
Franchise Taxes	Franchise Taxes  Franchise taxes are assessed to us by local governmental bodies, based on kWh delivered and are the principal component of taxes other than amounts related to income taxes as reported in the income statement. Franchise taxes are not a “pass through” item. The rates we charge customers are intended to recover the franchise taxes, but we are not acting as an agent to collect the taxes from customers.
Allowance For Funds Used During Construction (AFUDC)	Allowance for Funds Used During Construction (AFUDC)  AFUDC is a regulatory cost accounting procedu re whereby both interest charges on borrowed funds and a return on equity capital used to finance construction are included in the recorded cost of utility plant and equipment being constructed. AFUDC is capitalized on all projects involving construction periods lasting greater than thirty days. The equity portion, if any, of capitalized AFUDC is accounted for as other income. See Note 13 for detail of amounts charged to interest expense.
Cash And Cash Equivalents	Cash and Cash Equivalents  For purposes of reporting cash and cash equivalents, temporary cash investments purchased with a remaining maturity of three months or less are considered to be cash equivalents. See Note 13 for details regarding restricted cash.
Fair Value Of Nonderivative Financial Instruments	Fair Value of Nonderivative Financial Instruments  The carrying amounts for financial assets classified as current assets and the carrying amounts for financial liabilities classified as current liabilities approximate fair value due to the short maturity of such instruments. The fair values of other financial instruments, for which carrying amounts and fair values have not been presented, are not materially different than their related carrying amounts. The following discussion of fair value accounting standards applies primarily to our determination of the fair value of assets in the pension and OPEB plans trusts (see Note 10) and long-term debt (see Note 7).  Accounting standards related to the determination of fair value define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. We use a “mid-market” valuation convention (the mid-point price between bid and ask prices) as a practical expedient to measure fair value for the majority of our assets and liabilities subject to fair value measurement on a recurring basis. We primarily use the market approach for recurring fair value measurements and use valuation techniques to maximize the use of observable inputs and minimize the use of unobservable inputs.  We categorize our assets and liabilities recorded at fair value based upon the following fair value hierarchy:  · Level 1 valuations use quoted prices in active markets for identical assets or liabilities that are accessible at the measurement date. An active market is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis.  · Level 2 valuations use inputs that, in the absence of actively quoted market prices, are observable for the asset or liability, either directly or indirectly. Level 2 inputs include: (a) quoted prices for similar assets or liabilities in active markets , (b) quoted prices for identical or similar assets or liabilities in markets that are not active, (c) inputs other than quoted prices that are observable for the asset or liability such as interest rates and yield curves observable at commonly quoted intervals and (d) inputs that are derived principally from or corroborated by observable market data by correlation or other means. Our Level 2 valuations utilize over-the-counter broker quotes, quoted prices for similar assets or liabilities that are corroborated by correlations or other mathematical means and other valuation inputs.  · Level 3 valuations use unobservable inputs for the asset or liability. Unobservable inputs are used to the extent observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date. We use the most meaningful information available from the market combined with internally developed valuation methodologies to develop our best estimate of fair value.  We utilize several different valuation techniques to measure the fair value of assets and liabilities, relying primarily on the market approach of using prices and other market information for identical and/or comparable assets and liabilities for those items that are measured on a recurring basis.  The fair value of certain investments is measured using the net asset value (NAV) per share as a practical expedient. Such investments measured at NAV are not required to be categorized within the fair value hierarchy. See “Changes in Accounting Standards” below.
Consolidation Of Variable Interest Entities	Consolidation of Variable Interest Entities  A VIE is an entity with which we have a relationship or arrangement that indicates some level of control over the entity or results in economic risks to us. We consolidate a VIE if we have: a) the power to direct the significant activities of the VIE and b) the right or obligation to absorb profit and loss from the VIE (primary beneficiary). See Note 13.
Derivative Instruments And Mark-To-Market Accounting	Derivative Instruments and Mark-to-Market Accounting  We have from time-to-time entered into derivative instruments to hedge interest rate risk. If the instrument meets the definition of a derivative under accounting standards related to derivative instruments and hedging activities, the fair value of each derivative is recognized on the balance sheet as a derivative asset or liability and changes in the fair value are recognized in net income, unless criteria for certain exceptions are met. This recognition is referred to as “mark-to-market” accounting.
Changes In Accounting Standards	Changes in Accounting Standards  In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update 2016-2 (ASU 2016-2), Leases . ASU 2016-2 amends previous GAAP to require the balance sheet recognition of lease assets and liabilities for operating leases. We will be required to adopt ASU 2016-2 by January 1, 2019 and do not expect to early adopt. Retrospective application to the 2017 and 2018 comparative periods presented will be required in the year of adoption. The recognition of any lease obligation on the balance sheet will be classified as long-term debt for GAAP purposes and is defined as debt for our regulatory capital structure purposes (See Note 9 for details). Although any lease obligation will affect our balance sheet and capitalization ratios, the impact is not expected to be material. We continue to evaluate the impact of ASU 2016-2 on our financial statements.  Since May 2014, the FASB has issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers along with other supplemental guidance (together, Topic 606). Topic 606 introduces new, increased requirements for disclosure of revenue in financial statements and guidance that are intended to eliminate inconsistencies in the recognition of revenue. We will be required to adopt Topic 606 by January 1, 2018 and do not expect to early adopt. Our revenues from customers are tariff-based and are designed to recover the cost of providing electric delivery service to customers including a reasonable rate of return on invested capital. Revenues are generally recognized when the underlying service has been provided in an amount prescribed by the related tariff. At this time, we do not expect the new guidance to change this pattern of recognition and therefore it is not expected to have a material effect on our reported results of operations, financial condition or cash flows. We continue to evaluate the a pplication of the new guidance.  In May 2015, the FASB issued a new accounting standards update (ASU 2015-07), which removed the requirement to categorize within the fair value hierarchy all investments for which fair value is measured using the net asset value per share practical expedient. ASU 2015-07 is effective for fiscal years beginning after December 15, 2015 and was retrospectively adopted effective December 31, 2016. T he adoption impacted fair value measurement disclosures related to our pension and OPEB plans. See Note 10 - Pension and OPEB Plans.

Provision In Lieu Of Income T24

Provision In Lieu Of Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Provision In Lieu Of Income Taxes [Abstract]
Components Of Income Tax Provisions (Benefits)	  Year Ended December 31,  2016 2015 2014   Reported in operating expenses:  Current:  U.S. federal $ 60 $ 189 $ 113  State 20 32 24  Deferred:  U.S. federal 181 55 146  State - (13) -  Amortization of investment tax credits (2) (3) (3)  Total reported in operating expenses 259 260 280  Reported in other income and deductions:  Current:  U.S. federal (5) (7) (4)  State - - -  Deferred federal - (1) 2  Total reported in other income and deductions (5) (8) (2)  Total provision in lieu of income taxes $ 254 $ 252 $ 278 
Schedule Of Income Tax Reconciliation	  Year Ended December 31,  2016 2015 2014   Income before provision in lieu of income taxes $ 685 $ 684 $ 728  Provision in lieu of income taxes at the U.S. federal statutory rate of 35% $ 240 $ 239 $ 255  Amortization of investment tax credits – net of deferred tax effect (2) (3) (3)  Amortization (under regulatory accounting) of statutory tax rate changes (1) (1) (2)  Amortization of Medicare subsidy regulatory asset - - 14  Texas margin tax, net of federal tax benefit 13 13 16  Nondeductible losses (gains) on benefit plan investments - - (2)  Other, including audit settlements 4 4 -  Reported provision in lieu of income taxes $ 254 $ 252 $ 278  Effective rate 37.1% 36.8% 38.2% 
Schedule Of Changes To Uncertain Tax Positions	  2016 2015 2014   Balance at January 1, excluding interest and penalties $ 3 $ 2 $ 54  Additions based on tax positions related to prior years - - -  Reductions based on tax positions related to prior years - - (16)  Settlements with taxing authorities - 1 (36)  Balance at December 31, excluding interest and penalties $ 3 $ 3 $ 2 

Regulatory Assets and Liabili25

Regulatory Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2016
Regulatory Assets and Liabilities [Abstract]
Components Of Regulatory Assets And Liabilities	  Remaining Rate Recovery/Amortization Period at Carrying Amount At  December 31, 2016 December 31, 2016 December 31, 2015   Regulatory assets:  Generation-related regulatory assets securitized by transition bonds (a)(d) - $ - $ 31  Employee retirement costs being amortized 3 years 23 38  Unrecovered employee retirement costs incurred since the last rate review period (b) To be determined 327 291  Employee retirement liability (a)(b)(c) To be determined 849 853  Self-insurance reserve (primarily storm recovery costs) being amortized 3 years 64 95  Unrecovered self-insurance reserve incurred since the last rate review period (b) To be determined 367 332  Securities reacquisition costs (post-industry restructure) Lives of related debt 13 9  Recoverable amounts in lieu of deferred income taxes Life of related asset or liability 2 12  Deferred conventional meter and metering facilities depreciation Largely 4 years 78 100  Under-recovered AMS costs To be determined 205 164  Energy efficiency performance bonus (a) 1 year or less 10 10  Other regulatory assets Various 36 23  Total regulatory assets 1,974 1,958   Regulatory liabilities:  Estimated net removal costs Lives of related assets 819 686  Investment tax credit and protected excess deferred taxes Various 10 14  Over-collection of transition bond revenues (a)(d) - - 29  Over-recovered wholesale transmission service expense (a) 1 year or less 10 24  Other regulatory liabilities Various 17 11  Total regulatory liabilities 856 764  Net regulatory asset (e) $ 1,118 $ 1,194 ____________ (a) Not earning a return in the regulatory rate-setting process. (b) Recovery is specifically authorized by statute or by the PUCT, subject to reasonableness review. (c) Represents unfunded liabilities recorded in accordance with pension and OPEB accounting standards. (d) Bondco net regulatory liabilities at December 31, 2016 were zero . Bondco net regulatory assets of $10 million at December 31, 2015 consisted of $31 million included in generation-related regulatory assets net of the regulatory liability for over-collection of transition bond revenues of $21 million (excludes $8 million of over-collections related to transition bonds assumed by Oncor for final settlement). (e) For year-end 2016, regulatory assets and liabilities are presented gross on the balance sheet.

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Long-Term Debt [Abstract]
Schedule Of Long-Term Debt	  December 31,  2016 2015   Oncor (a):  5.000% Fixed Senior Notes due September 30, 2017 $ 324 $ 324  6.800% Fixed Senior Notes due September 1, 2018 550 550  2.150% Fixed Senior Notes due June 1, 2019 250 250  5.750% Fixed Senior Notes due September 30, 2020 126 126  4.100% Fixed Senior Notes due June 1, 2022 400 400  7.000% Fixed Debentures due September 1, 2022 800 800  2.950% Fixed Senior Notes due April 1, 2025 350 350  7.000% Fixed Senior Notes due May 1, 2032 500 500  7.250% Fixed Senior Notes due January 15, 2033 350 350  7.500% Fixed Senior Notes due September 1, 2038 300 300  5.250% Fixed Senior Notes due September 30, 2040 475 475  4.550% Fixed Senior Notes due December 1, 2041 400 400  5.300% Fixed Senior Notes due June 1, 2042 500 500  3.750% Fixed Senior Notes due April 1, 2045 550 375  Unamortized discount and debt issuance costs (36) (54)  Less amount due currently (324) -  Long-term debt, less amounts due currently — Oncor 5,515 5,646   Bondco (b):  5.290% Fixed Series 2004 Bonds due in semiannual installments through May 15, 2016 - 41  Total - 41  Less amount due currently (41)  Long-term debt, less amounts due currently — Bondco - -  Total long-term debt, less amounts due currently $ 5,515 $ 5,646 __________ (a) Secured by first priority lien on certain transmission and distribution assets equally and ratably with all of Oncor’s other secured indebtedness. See “Deed of Trust” below for additional information. (b) The transition bonds were nonrecourse to Oncor and were issued to securitize a regulatory asset.
Schedule Of Long-Term Debt Maturity	  Year Amount  2017 $ 324  2018 550  2019 250  2020 126  2021 -  Thereafter 4,625  Unamortized discount and debt issuance costs (36)  Total $ 5,839 

Commitments And Contingencies (

Commitments And Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies [Abstract]
Schedule Of Future Miinimum Lease Payments Under Operating Leases	  Year Amount  2017 $ 6  2018 1  2019 1  2020 -  2021 -  Thereafter -  Total future minimum lease payments $ 8 

Membership Interests (Tables)

Membership Interests (Tables)	12 Months Ended
	Dec. 31, 2016
Membership Interests [Abstract]
Schedule Of Distributions Paid	During 2016, our board of directors declared, and we paid, the following cash distributions to our members:   Declaration Date Payment Date Amount  October 26, 2016 October 27, 2016 $ 41  July 27, 2016 August 11, 2016 $ 68  April 27, 2016 May 11, 2016 $ 65  February 24, 2016 February 25, 2016 $ 56   During 2015, our board of directors declared, and we paid, the following cash distributions to our members:   Declaration Date Payment Date Amount  December 9, 2015 December 11, 2015 $ 18  October 27, 2015 November 9, 2015 $ 135  July 29, 2015 August 10, 2015 $ 118  April 29, 2015 May 15, 2015 $ 65  February 25, 2015 February 26, 2015 $ 100 
Schedule Of Changes To Accumulated Other Comprehensive Income (Loss)	The following table present s the changes to accumulated other comprehensive income (loss) for the year s ended December 31, 201 6, 2015 and 2014 .   Cash Flow Hedges – Interest Rate Swap Defined Benefit Pension and OPEB Plans Accumulated Other Comprehensive Income (Loss)   Balance at December 31, 2015 $ (22) $ (91) $ (113)  Defined benefit pension plans (net of tax) - - -  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2016 $ (20) $ (91) $ (111)   Balance at December 31, 2014 $ (24) $ (83) $ (107)  Defined benefit pension plans (net of tax) - (8) (8)  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2015 $ (22) $ (91) $ (113)   Balance at December 31, 2013 $ (26) $ (22) $ (48)  Defined benefit pension plans (net of tax) - (61) (61)  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2014 $ (24) $ (83) $ (107)     

Pension and OPEB Plans (Tables)

Pension and OPEB Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Schedule Of Pension And OPEB Plan Costs	  Year Ended December 31,  2016 2015 2014   Pension costs $ 76 $ 104 $ 58  OPEB costs 62 53 48  Total benefit costs 138 157 106  Less amounts recognized principally as property or a regulatory asset (100) (113) (69)  Net amounts recognized as expense $ 38 $ 44 $ 37 
Schedule Of Detailed Pension And OPEB Benefit Information	Detailed Information Regarding Pension and OPEB Benefits  The following pension and OPEB information is based on December 31, 201 6 , 201 5 and 201 4 measurement dates:   Pension Plans OPEB Plan  Year Ended December 31, Year Ended December 31,  2016 2015 2014 2016 2015 2014  Assumptions Used to Determine Net Periodic Pension and OPEB Costs: Discount rate (a) 4.30% 3.96% 4.74% 4.60% 4.23% 4.98% Expected return on plan assets 5.54% 5.26% 6.47% 6.30% 6.65% 7.05% Rate of compensation increase 3.29% 3.29% 3.94% - - -  Components of Net Pension and OPEB Costs: Service cost $ 23 $ 25 $ 23 $ 7 $ 7 $ 6 Interest cost 134 131 132 49 43 44 Expected return on assets (122) (115) (136) (9) (10) (12) Amortization of prior service cost (credit) - - - (20) (20) (20) Amortization of net loss 41 63 39 35 33 30 Net periodic pension and OPEB costs $ 76 $ 104 $ 58 $ 62 $ 53 $ 48  Other Changes in Plan Assets and Benefit Obligations Recognized as Regulatory Assets or in Other Comprehensive Income: Net loss (gain) $ 41 $ 37 $ 388 $ 10 $ 39 $ 128 Amortization of net loss (41) (63) (39) (35) (33) (30) Amortization of prior service (cost) credit - - - 20 20 20 Total recognized as regulatory assets or other comprehensive income - (26) 349 (5) 26 118 Total recognized in net periodic pension and OPEB costs and as regulatory assets or other comprehensive income $ 76 $ 78 $ 407 $ 57 $ 79 $ 166 _______________ (a) As a result of the transfer of OPEB plan assets and liabilities from the EFH OPEB Plan to the Oncor OPEB Plan discussed above, the discount rate reflected in OPEB costs for January through June 2014 was 4.98% and for July through December 2014 was 4.39% .   Pension Plans OPEB Plan  Year Ended December 31, Year Ended December 31,  2016 2015 2014 2016 2015 2014  Assumptions Used to Determine Benefit Obligations at Period End: Discount rate 4.05% 4.30% 3.96% 4.35% 4.60% 4.23% Rate of compensation increase 3.33% 3.29% 3.29% - - -     Pension Plans OPEB Plan  Year Ended December 31, Year Ended December 31,  2016 2015 2016 2015  Change in Projected Benefit Obligation: Projected benefit obligation at beginning of year $ 3,201 $ 3,379 $ 1,088 $ 1,054 Service cost 23 25 7 7 Interest cost 134 131 49 43 Participant contributions - - 17 15 Assumption of liabilities - - 7 - Actuarial (gain) loss 106 (181) 10 25 Benefits paid (157) (153) (62) (56) Projected benefit obligation at end of year $ 3,307 $ 3,201 $ 1,116 $ 1,088 Accumulated benefit obligation at end of year $ 3,213 $ 3,100 $ - $ -  Change in Plan Assets: Fair value of assets at beginning of year $ 2,252 $ 2,454 $ 141 $ 161 Actual return (loss) on assets 188 (103) 9 (4) Employer contributions 4 54 31 25 Assets related to assumed liabilities - - 7 - Participant contributions - - 17 15 Benefits paid (157) (153) (62) (56) Fair value of assets at end of year $ 2,287 $ 2,252 $ 143 $ 141  Funded Status: Projected benefit obligation at end of year $ (3,307) $ (3,201) $ (1,116) $ (1,088) Fair value of assets at end of year 2,287 2,252 143 141 Funded status at end of year $ (1,020) $ (949) $ (973) $ (947)    Pension Plans OPEB Plan  Year Ended December 31, Year Ended December 31,  2016 2015 2016 2015  Amounts Recognized in the Balance Sheet Consist of: Liabilities: Other current liabilities $ (4) $ (4) $ - $ - Other noncurrent liabilities (1,016) (945) (973) (947) Net liability recognized $ (1,020) $ (949) $ (973) $ (947) Regulatory assets: Net loss $ 583 $ 583 $ 296 $ 320 Prior service cost (credit) - - (30) (50) Net regulatory asset recognized $ 583 $ 583 $ 266 $ 270 Accumulated other comprehensive net loss $ 136 $ 136 $ 4 $ 4 
Schedule Of Assumed Health Care Cost Trend Rates	  Year Ended December 31,  2016 2015   Assumed Health Care Cost Trend Rates – Not Medicare Eligible:  Health care cost trend rate assumed for next year 5.80% 6.00%  Rate to which the cost trend is expected to decline (the ultimate trend rate) 5.00% 5.00%  Year that the rate reaches the ultimate trend rate 2024 2024   Assumed Health Care Cost Trend Rates – Medicare Eligible:  Health care cost trend rate assumed for next year 5.70% 5.80%  Rate to which the cost trend is expected to decline (the ultimate trend rate) 5.00% 5.00%  Year that the rate reaches the ultimate trend rate 2024 2024  1-Percentage Point Increase 1-Percentage Point Decrease   Sensitivity Analysis of Assumed Health Care Cost Trend Rates:  Effect on accumulated postretirement obligation $ 152 $ (125)  Effect on postretirement benefits cost 8 (7) 
Schedule Of Projected Benefit Obligations And Accumulated Benefit Obligations In Excess Of Plan Assets Fair Value	  At December 31,  2016 2015   Pension Plan with PBO and ABO in Excess of Plan Assets:  Projected benefit obligations $ 3,137 $ 3,035  Accumulated benefit obligations 3,051 2,944  Plan assets 2,112 2,085 
Schedule Of Target Asset Allocation Ranges By Asset Category	  Target Allocation Ranges  Asset Category Recoverable Nonrecoverable   International equities 14% - 18% 5% - 9%  U.S. equities 17% - 21% 6% - 10%  Real estate 4% - 5% -  Credit strategies 6% - 8% 4% - 6%  Fixed income 48% - 60% 76% - 84% 
Schedule Of Expected Long-Term Rate Of Return On Assets Assumptions	  Pension Plans OPEB Plan  Asset Class Expected Long-Term Rate of Return Asset Class Expected Long-Term Rate of Return   International equity securities 6.98% 401(h) accounts 6.60%  U.S. equity securities 6.40% Life insurance VEBA 6.01%  Real estate 5.00% Union VEBA 6.01%  Credit strategies 5.22% Non-union VEBA 2.20%  Fixed income securities 4.50% Weighted average 6.10%  Weighted average (a) 5.46% _____________ (a) The 2017 expected long-term rate of return for the nonregulated portion of the Oncor Retirement Plan is 4.62% and 5.13% for Oncor's portion of the Vistra Retirement Plan. 
Schedule Of Contributions	  Year Ended December 31,  2016 2015 2014   Pension plans contributions $ 4 $ 54 $ 68  OPEB plan contributions 31 25 18  Total contributions $ 35 $ 79 $ 86 
Schedule Of Estimated Future Benefit Payments	  2017 2018 2019 2020 2021 2022-26   Pension plans $ 173 $ 179 $ 184 $ 190 $ 195 $ 1,032  OPEB plan $ 52 $ 55 $ 57 $ 60 $ 63 $ 338 
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule Of Assets Fair Value Measured On Recurring Basis	   At December 31, 2016  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ - $ 14 $ - $ 14  Equity securities:  U.S. 193 3 - 196  International 225 - - 225  Fixed income securities:  Corporate bonds (a) - 1,089 - 1,089  U.S. Treasuries - 223 - 223  Other (b) - 40 - 40  Real estate - - 5 5  Total assets in the fair value hierarchy $ 418 $ 1,369 $ 5 1,792  Total assets measured at net asset value (c) 495  Total fair value of plan assets $ 2,287   At December 31, 2015 (d)  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ - $ 21 $ - $ 21  Equity securities:  U.S. 201 8 - 209  International 255 1 - 256  Fixed income securities:  Corporate bonds (a) - 1,098 - 1,098  U.S. Treasuries - 189 - 189  Other (b) - 46 - 46  Real estate - - 5 5  Total assets in the fair value hierarchy $ 456 $ 1,363 $ 5 $ 1,824  Total assets measured at net asset value (c) 428  Total fair value of plan assets $ 2,252 _____________ (a) Substantially all corporate bonds are rated investment grade by a major ratings agency such as Moody’s. (b) Other consists primarily of municipal bonds, emerging market debt, bank loans and fixed income derivative instruments. (c) Fair value was measured using the net asset value (NAV) per share as a practical expedient as the investments did not have a readily determinable fair value and are not required to be classified in the fair value hierarchy. The NAV fair value amounts presented here are intended to permit a reconciliation to the total fair value of plan assets. (d) 2015 presentation has been revised to reflect the application of ASU 2015-07 consistent with 2016 (see Note 1). 
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule Of Assets Fair Value Measured On Recurring Basis	  At December 31, 2016  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ 2 $ - $ - $ 2  Equity securities:  U.S. 41 - - 41  International 28 - - 28  Fixed income securities:  Corporate bonds (a) - 28 - 28  U.S. Treasuries - 2 - 2  Other (b) 28 - - 28  Total assets in the fair value hierarchy $ 99 $ 30 $ - 129  Total assets measured at net asset value (c) 14  Total fair value of plan assets $ 143   At December 31, 2015 (d)  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ 4 $ 1 $ - $ 5  Equity securities:  U.S. 39 - - 39  International 25 - - 25  Fixed income securities:  Corporate bonds (a) - 29 - 29  U.S. Treasuries - 1 - 1  Other (b) 35 1 - 36  Total assets in the fair value hierarchy $ 103 $ 32 $ - 135  Total assets measured at net asset value (c) 6  Total fair value of plan assets $ 141 _____________ (a) Substantially all corporate bonds are rated investment grade by a major ratings agency such as Moody’s. (b) Other consists primarily of diversified bond mutual funds. (c) Fair value was measured using the net asset value (NAV) per share as a practical expedient as the investments did not have a readily determinable fair value and are not required to be classified in the fair value hierarchy. The NAV fair value amounts presented here are intended to permit a reconciliation to the total fair value of plan assets. (d) 2015 presentation has been revised to reflect the application of ASU 2015-07 consistent with 2016 (see Note 1). 

Related-Party Transactions (Tab

Related-Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2016
Related-Party Transactions [Abstract]
Schedule Of Trade Accounts And Other Receivables From Related Parties	  At December 31,  2015   Trade accounts and other receivables from affiliates $ 120  Trade accounts and other payables to affiliates (2)  Trade accounts and other receivables from affiliates – net $ 118 
Schedule Of Related Party Transactions	Amounts payable to (receivable from) members related to income taxes under the agreement and reported on our balance sheet consisted of the following:    At December 31, 2016 At December 31, 2015  EFH Corp. Texas Transmission Total EFH Corp. Texas Transmission Total   Federal income taxes receivable $ (62) $ (18) $ (80) $ (109) $ (27) $ (136)  Texas margin taxes payable 20 - 20 20 - 20  Net payable (receivable) $ (42) $ (18) $ (60) $ (89) $ (27) $ (116)  Cash payments made to (received from) members related to income taxes consisted of the following:     Year Ended December 31, 2016 Year Ended December 31, 2015 Year Ended December 31, 2014  EFH Corp. Texas Transm. Total EFH Corp. Texas Transm. Total EFH Corp. Texas Transm. Total   Federal income taxes $ - $ - $ - $ 108 $ 27 $ 135 $ 215 $ 54 $ 269  Texas margin taxes 20 - 20 24 - 24 22 - 22  Total payments (receipts) $ 20 $ - $ 20 $ 132 $ 27 $ 159 $ 237 $ 54 $ 291 ______________

Supplementary Financial Infor31

Supplementary Financial Information (Tables)	12 Months Ended
	Dec. 31, 2016
Supplementary Financial Information [Abstract]
Schedule Of Other Income And (Deductions)	Other Income and Deductions  Year Ended December 31,  2016 2015 2014   Accretion of fair value adjustment (discount) to regulatory assets due to acquisition accounting $ 1 $ 5 $ 12  Professional fees (15) (19) (14)  Non-recoverable pension and OPEB (Note 9) (2) (9) (1)  Interest income 2 - 3  Other (1) 1 1  Total other income and (deductions) - net $ (15) $ (22) $ 1 
Schedule Of Interest Expense And Related Charges	  Year Ended December 31,  2016 2015 2014   Interest $ 341 $ 335 $ 355  Amortization of debt issuance costs and discounts 3 3 3  Less allowance for funds used during construction – capitalized interest portion (8) (5) (5)  Total interest expense and related charges $ 336 $ 333 $ 353 
Schedule Of Restricted Cash	  At December 31, 2015  Current Assets   Customer collections related to transition bonds used only to service debt and pay expenses $ 22  Reserve for fees associated with transition bonds 10  Reserve for shortfalls of transition bond charges 6  Total restricted cash $ 38 
Schedule Of Trade Accounts And Other Receivables	  At December 31,  2016 2015   Gross trade accounts and other receivables $ 548 $ 509  Trade accounts and other receivables from TCEH (affiliated) - (118)  Allowance for uncollectible accounts (3) (3)  Trade accounts receivable from nonaffiliates – net $ 545 $ 388 
Summary of Investments And Other Property	  At December 31,  2016 2015   Assets related to employee benefit plans, including employee savings programs $ 98 $ 94  Land 2 3  Total investments and other property $ 100 $ 97 
Schedule Of Property, Plant And Equipment	  Composite Depreciation Rate/ At December 31,  Avg. Life at December 31, 2016 2016 2015  Assets in service:  Distribution 3.9% / 25.5 years $ 11,369 $ 10,861  Transmission 2.8% / 35.2 years 7,734 7,209  Other assets 9.0% / 11.1 years 1,131 1,002  Total 20,234 19,072  Less accumulated depreciation 6,836 6,479  Net of accumulated depreciation 13,398 12,593  Construction work in progress 416 416  Held for future use 15 15  Property, plant and equipment – net $ 13,829 $ 13,024 
Schedule Of Intangible Assets	  At December 31, 2016 At December 31, 2015  Gross Gross  Carrying Accumulated Carrying Accumulated  Amount Amortization Net Amount Amortization Net  Identifiable intangible assets subject to amortization included in property, plant and equipment:  Land easements $ 491 $ 94 $ 397 $ 467 $ 91 $ 376  Capitalized software 470 326 144 435 269 166  Total $ 961 $ 420 $ 541 $ 902 $ 360 $ 542 
Schedule Of Estimated Aggregate Amortization Expenses	  Year Amortization Expense   2017 $ 56  2018 50  2019 47  2020 46  2021 46 
Schedule Of Employee Benefit Obligations And Other	  At December 31,  2016 2015   Retirement plans and other employee benefits $ 2,092 $ 1,985  Uncertain tax positions (including accrued interest) 3 3  Amount payable related to income taxes - -  Investment tax credits 12 15  Other 61 60  Total other noncurrent liabilities and deferred credits $ 2,168 $ 2,063 
Schedule Of Supplemental Cash Flow Information	  Year Ended December 31,  2016 2015 2014   Cash payments related to:  Interest $ 336 $ 346 $ 356  Less capitalized interest (8) (5) (5)  Interest payments (net of amounts capitalized) $ 328 $ 341 $ 351  Amount in lieu of income taxes:  Federal $ - $ 135 $ 269  State 20 43 22  Total amount in lieu of income taxes $ 20 $ 178 $ 291  Noncash construction expenditures (a) $ 122 $ 56 $ 82 ______________ (a) Represents end-of-period accruals.
Schedule Of Quarterly Information	  2016 First Quarter Second Quarter Third Quarter Fourth Quarter   Operating revenues $ 943 $ 948 $ 1,071 $ 958  Operating income 169 196 250 162  Net income 81 110 163 77   2015 First Quarter Second Quarter Third Quarter Fourth Quarter   Operating revenues $ 946 $ 938 $ 1,072 $ 922  Operating income 180 186 253 160  Net income 98 98 163 73 

Description Of Business And S32

Description Of Business And Significant Accounting Policies (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)entity	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2004USD ($)	Dec. 31, 2003USD ($)
Business And Significant Accounting Polices [Line Items]
Number of entities that would possibly be bankrupt | entity	1
Long-lived assets and goodwill impairments	$ 0	$ 0	$ 0
Oncor Holdings [Member]
Business And Significant Accounting Polices [Line Items]
Ownership	80.03%
Texas Transmission [Member]
Business And Significant Accounting Polices [Line Items]
Percentage of membership interest owned by non-controlling owners	19.75%
Bondco [Member]
Business And Significant Accounting Polices [Line Items]
Principal amount of transition bonds issued				$ 1,300	$ 1,300
Sales [Member] | Vistra [Member]
Business And Significant Accounting Polices [Line Items]
Concentration risk percentage	23.00%	25.00%	25.00%

EFH Bankruptcy Proceedings (Det

EFH Bankruptcy Proceedings (Details) - USD ($) $ in Millions	Oct. 30, 2016	Oct. 29, 2016	Dec. 31, 2016
Bankruptcy [Line Items]
Amount collected from related party			$ 129
Plan Of Reorganization [Member]
Bankruptcy [Line Items]
Percent of outstanding equity interests required			80.00%
OMI Agreement [Member]
Bankruptcy [Line Items]
Percent of outstanding equity interests required		0.22%
Limited liability company interests, shares		1,396,008
Limited liability company interests, value		$ 27
EFH Corp [Member] | NEE Merger Agreement [Member]
Bankruptcy [Line Items]
Agreement extension period			90 days
Termination fee			$ 275
Texas Holdings Group [Member] | TTI Merger Agreement [Member]
Bankruptcy [Line Items]
Percent of outstanding equity interests required	19.75%
Purchase price	$ 2,400

Regulatory Matters (Details)

Regulatory Matters (Details)	Dec. 31, 2016item
Regulatory Matters [Abstract]
Number of cities resolutions passed over electric utility rates	58
Number of original jurisdiction cities	204
Number of other parties appealed various portions of rate review final order to state district court	4
Number of issues revised judgment	2

Provision In Lieu Of Income T35

Provision In Lieu Of Income Taxes (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Liability in lieu of deferred income taxes			$ 2,788	$ 2,612
Increase (Decrease) in liability for uncertain tax positions		$ (18)
Increase (Decrease) in liability for deferred income taxes		16
Reversal of accrued interest and tax		2
Reversal of accrued interest and tax after tax		$ 1
Unrecognized tax benefits	$ 2		3	3				$ 54
Reversal of provision in lieu of income taxes							$ 1
Uncertain tax positions related to timing of recognition			3	3
Accrued interest			0	0
Benefit (expense) from interest and penalties	1		$ 0	$ 0
Tax Year 2003 To 2006 [Member]
Related Party Transaction [Line Items]
Liability in lieu of deferred income taxes	11
Increase (Decrease) in liability for uncertain tax positions	$ (35)
Tax Year 2007 [Member]
Related Party Transaction [Line Items]
Unrecognized tax benefits							1
Tax Year 2007 [Member] | EFH Corp [Member]
Related Party Transaction [Line Items]
Liability in lieu of deferred income taxes							$ 45
Tax Year 2008 and 2009 [Member] | EFH Corp [Member]
Related Party Transaction [Line Items]
Liability in lieu of deferred income taxes						$ 4
Income tax refunds from members					$ 4	$ 8

Provision In Lieu Of Income T36

Provision In Lieu Of Income Taxes (Components Of Income Tax Provisions (Benefits)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Provision In Lieu Of Income Taxes [Abstract]
Current: U.S. federal	$ 60	$ 189	$ 113
Current: State	20	32	24
Deferred: U.S. federal	181	55	146
Deferred: State		(13)
Amortization of investment tax credits	(2)	(3)	(3)
Total reported in operating expenses	259	260	280
U.S. federal	(5)	(7)	(4)
Deferred federal		(1)	2
Total reported in other income and deductions	(5)	(8)	(2)
Total provision in lieu of income taxes	$ 254	$ 252	$ 278

Provision In Lieu Of Income T37

Provision In Lieu Of Income Taxes (Schedule Of Income Tax Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Provision In Lieu Of Income Taxes [Abstract]
Income before provision in lieu of income taxes	$ 685	$ 684	$ 728
Provision in lieu of income taxes at the U.S. federal statutory rate of 35%	240	239	255
Amortization of investment tax credits - net of deferred tax effect	(2)	(3)	(3)
Amortization (under regulatory accounting) of statutory tax rate changes	(1)	(1)	(2)
Amortization of Medicare subsidy regulatory asset			14
Texas margin tax, net of federal tax benefit	13	13	16
Nondeductible losses (gains) on benefit plan investments			(2)
Other, including audit settlements	4	4
Total provision in lieu of income taxes	$ 254	$ 252	$ 278
Effective rate	37.10%	36.80%	38.20%
U.S. federal statutory rate	35.00%	35.00%	35.00%

Provision In Lieu Of Income T38

Provision In Lieu Of Income Taxes (Schedule Of Changes To Uncertain Tax Positions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Provision In Lieu Of Income Taxes [Abstract]
Balance at January 1, excluding interest and penalties	$ 3	$ 2	$ 54
Additions based on tax positions related to prior years
Reductions based on tax positions related to prior years			(16)
Settlements with taxing authorities, increase		1
Settlements with taxing authorities, decrease			(36)
Balance at December 31, excluding interest and penalties	$ 3	$ 3	$ 2

Regulatory Assets And Liabili39

Regulatory Assets And Liabilities (Narrative) (Details) - USD ($)		Oct. 10, 2007	Dec. 31, 2016	Dec. 31, 2015
Regulatory Assets And Liabilities [Line Items]
Expected surcharge			$ 1,023,000,000
Recovery period			11 years
Net regulatory asset	[1]		$ 1,118,000,000	$ 1,194,000,000
Residential Retail Customer [Member]
Regulatory Assets And Liabilities [Line Items]
Cost recovery factor			2.19
Minimum [Member] | Non-Residential Retail Customer [Member]
Regulatory Assets And Liabilities [Line Items]
Cost recovery factor			2.39
Maximum [Member] | Non-Residential Retail Customer [Member]
Regulatory Assets And Liabilities [Line Items]
Cost recovery factor			5.15
Over-Collection Of Transition Bond Revenues [Member]
Regulatory Assets And Liabilities [Line Items]
Recovery period		9 years
Generation Related Regulatory Assets Securitized by Transition Bonds [Member]
Regulatory Assets And Liabilities [Line Items]
Reduction in regulatory assets net of regulatory liability			$ 213,000,000
[1]	For year-end 2016, regulatory assets and liabilities are presented gross on the balance sheet.

Regulatory Assets And Liabili40

Regulatory Assets And Liabilities (Components Of Regulatory Assets And Liabilities) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Regulatory Assets And Liabilities [Line Items]
Carrying Amount, Regulatory Assets		$ 1,974	$ 1,958
Carrying Amount, Regulatory Liabilities		856	764
Net regulatory asset	[1]	1,118	1,194
Bondco [Member]
Regulatory Assets And Liabilities [Line Items]
Carrying Amount, Regulatory Assets			10
Carrying Amount, Regulatory Liabilities		$ 0
Net regulatory asset			10
Estimated Net Removal Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		Lives of related assets
Carrying Amount, Regulatory Liabilities		$ 819	686
Investment Tax Credit and Protected Excess Deferred Taxes [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		Various
Carrying Amount, Regulatory Liabilities		$ 10	14
Over-Collection Of Transition Bond Revenues [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[2],[3]	-
Carrying Amount, Regulatory Liabilities	[2],[3]		29
Over-Collection Of Transition Bond Revenues [Member] | Bondco [Member]
Regulatory Assets And Liabilities [Line Items]
Carrying Amount, Regulatory Liabilities			21
Over-Recovered Wholesale Transmission Service Expense [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[3]	1 year or less
Carrying Amount, Regulatory Liabilities	[3]	$ 10	24
Other Regulatory Liabilities [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		Various
Carrying Amount, Regulatory Liabilities		$ 17	11
Excluded Over-Collected Series 2003-1 Transition Bond Revenues [Member]
Regulatory Assets And Liabilities [Line Items]
Carrying Amount, Regulatory Liabilities			8
Generation Related Regulatory Assets Securitized by Transition Bonds [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[2],[3]	-
Carrying Amount, Regulatory Assets	[2],[3]		31
Generation Related Regulatory Assets Securitized by Transition Bonds [Member] | Bondco [Member]
Regulatory Assets And Liabilities [Line Items]
Net regulatory asset			31
Employee Retirement Costs Being Amortized [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		3 years
Carrying Amount, Regulatory Assets		$ 23	38
Unrecovered Employee Retirement Costs Incurred Since The Last Rate Review Period [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[4]	To be determined
Carrying Amount, Regulatory Assets	[4]	$ 327	291
Employee Retirement Liability [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[3],[4],[5]	To be determined
Carrying Amount, Regulatory Assets	[3],[4],[5]	$ 849	853
Self Insurance Reserve (Primarily Storm Recovery Costs) Being Amortized [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		3 years
Carrying Amount, Regulatory Assets		$ 64	95
Unrecovered Self-Insurance Reserve Incurred Since The Last Rate Review Period [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[4]	To be determined
Carrying Amount, Regulatory Assets	[4]	$ 367	332
Securities Reacquisition Costs (Post-Industry Restructure) [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		Lives of related debt
Carrying Amount, Regulatory Assets		$ 13	9
Recoverable Amounts In Lieu Of Deferred Income Taxes [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		Life of related asset or liability
Carrying Amount, Regulatory Assets		$ 2	12
Deferred Conventional Meter And Metering Facilities Depreciation [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		Largely 4 years
Carrying Amount, Regulatory Assets		$ 78	100
Under-recovered AMS Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		To be determined
Carrying Amount, Regulatory Assets		$ 205	164
Net regulatory asset		$ 205	164
Energy Efficiency Performance Bonus [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[3]	1 year or less
Carrying Amount, Regulatory Assets	[3]	$ 10	10
Other Regulatory Assets [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		Various
Carrying Amount, Regulatory Assets		$ 36	$ 23
[1]	For year-end 2016, regulatory assets and liabilities are presented gross on the balance sheet.
[2]	Bondco net regulatory liabilities at December 31, 2016 were zero. Bondco net regulatory assets of $10 million at December 31, 2015 consisted of $31 million included in generation-related regulatory assets net of the regulatory liability for over-collection of transition bond revenues of $21 million (excludes $8 million of over-collections related to transition bonds assumed by Oncor for final settlement).For year-end 2016, regulatory assets and liabilities are presented gross on the balance sheet.
[3]	Not earning a return in the regulatory rate-setting process.
[4]	Recovery is specifically authorized by statute or by the PUCT, subject to reasonableness review.
[5]	Represents unfunded liabilities recorded in accordance with pension and OPEB accounting standards.

Borrowings Under Credit Facil41

Borrowings Under Credit Facilities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)contract	Dec. 31, 2015USD ($)
Line of Credit Facility [Line Items]
Outstanding borrowing under the revolving credit facility	$ 789	$ 840
Outstanding borrowing, interest rate	1.72%	1.48%
Letters of credit	$ 7	$ 7
Commitment fee	0.10%
Borrowing capacity available under the credit facility	$ 1,204	$ 1,153
Maximum [Member]
Line of Credit Facility [Line Items]
Commitment fee	0.275%
Debt-to-capitalization ratio	1
Minimum [Member]
Line of Credit Facility [Line Items]
Commitment fee	0.10%
Debt-to-capitalization ratio	0.47
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Outstanding borrowing, interest rate	1.20%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 2,000
Number of exercised extensions of revolving credit facility | contract	1
Number of revolving credit facilities extension options | contract	2
Extension period for revolving line of credit	1 year
Expiration of revolving credit facility	Oct. 31, 2018
Additional increase in borrowing capacity amount	$ 100
Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt-to-capitalization ratio	1
Revolving Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Debt-to-capitalization ratio	0.65
London Interbank Offered Rate (LIBOR) [Member]
Line of Credit Facility [Line Items]
Spread over variable rate	1.00%
London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Spread over variable rate	1.75%
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Spread over variable rate	1.00%
Federal Funds Effective Rate [Member]
Line of Credit Facility [Line Items]
Spread over variable rate	0.50%
One-Month London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Spread over variable rate	1.00%
One-Month London Interbank Offered Rate [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Spread over variable rate	0.75%
One-Month London Interbank Offered Rate [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Spread over variable rate	0.00%

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Aug. 31, 2016
Long-Term Debt [Line Items]
Repayments of long-term debt		$ 41,000,000	$ 639,000,000	$ 131,000,000
Proceeds from sale of Notes	$ 714,000,000
Percentage of principal amount plus accrued and unpaid interest and make-whole premium		100.00%
Percentage of fair value of cost of property additions certified to the Deed of Trust collateral agent		85.00%
Available bond credits		$ 2,625,000,000
Note redemption price to principal amount, percentage		100.00%
Future debt subject to property additions to the Deed of Trust		$ 1,739,000,000
Estimated fair value of our long-term debt including current maturities		6,751,000,000	6,287,000,000
Carrying amount		$ 5,839,000,000	$ 5,687,000,000
3.750% Fixed Senior Notes due April 1, 2045 [Member]
Long-Term Debt [Line Items]
Interest percentage	3.75%	3.75%	3.75%
Due date		Apr. 1, 2045
Additional 2045 Notes [Member]
Long-Term Debt [Line Items]
Debt principal amount	$ 375,000,000				$ 175,000,000
Proceeds from sale of Notes		$ 185,000,000
Percentage of principal amount plus accrued and unpaid interest and make-whole premium		100.00%
Due date		Oct. 1, 2044
6.375% Fixed Senior Notes Due January 15, 2015 [Member]
Long-Term Debt [Line Items]
Repayments of long-term debt		$ 639,000,000
Debt principal amount			$ 500,000,000
Interest percentage			6.375%
Due date		Jan. 15, 2015
Transition Bond [Member]
Long-Term Debt [Line Items]
Debt principal amount		$ 139,000,000

Long-Term Debt (Schedule Of Lon

Long-Term Debt (Schedule Of Long-Term Debt) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015		Mar. 31, 2015
Debt Instrument [Line Items]
Unamortized discount and debt issuance costs	[1]	$ (36)		$ (54)
Less amount due currently	[1]	(324)
Total long-term debt, less amounts due currently	[1]	5,515		5,646
5.000% Fixed Senior Notes Due September 30, 2017 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 324		$ 324
Interest percentage	[1]	5.00%		5.00%
Due date	[1]	Sep. 30, 2017
6.800% Fixed Senior Notes Due September 1, 2018 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 550		$ 550
Interest percentage	[1]	6.80%		6.80%
Due date	[1]	Sep. 1, 2018
2.150% Fixed Senior Notes Due June 1, 2019 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 250		$ 250
Interest percentage	[1]	2.15%		2.15%
Due date	[1]	Jun. 1, 2019
5.750% Fixed Senior Notes Due September 30, 2020 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 126		$ 126
Interest percentage	[1]	5.75%		5.75%
Due date	[1]	Sep. 30, 2020
4.100% Fixed Senior Notes Due June 1, 2022 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 400		$ 400
Interest percentage	[1]	4.10%		4.10%
Due date	[1]	Jun. 1, 2022
7.000% Fixed Debentures Due September 1, 2022 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 800		$ 800
Interest percentage	[1]	7.00%		7.00%
Due date	[1]	Sep. 1, 2022
2.950% Fixed Senior Notes due April 1, 2025 [Member]
Debt Instrument [Line Items]
Fixed Senior Note		$ 350	[1]	$ 350	[1]	$ 350
Interest percentage		2.95%	[1]	2.95%	[1]	2.95%
Due date	[1]	Apr. 1, 2025
7.000% Fixed Senior Notes Due May 1, 2032 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 500		$ 500
Interest percentage	[1]	7.00%		7.00%
Due date	[1]	May 1, 2032
7.250% Fixed Senior Notes Due January 15, 2033 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 350		$ 350
Interest percentage	[1]	7.25%		7.25%
Due date	[1]	Jan. 15, 2033
7.500% Fixed Senior Notes Due September 1, 2038 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 300		$ 300
Interest percentage	[1]	7.50%		7.50%
Due date	[1]	Sep. 1, 2038
5.250% Fixed Senior Notes Due September 30, 2040 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 475		$ 475
Interest percentage	[1]	5.25%		5.25%
Due date	[1]	Sep. 30, 2040
4.550% Fixed Senior Notes Due December 1, 2041 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 400		$ 400
Interest percentage	[1]	4.55%		4.55%
Due date	[1]	Dec. 1, 2041
5.300% Fixed Senior Notes Due June 1, 2042 [Member]
Debt Instrument [Line Items]
Fixed Senior Note	[1]	$ 500		$ 500
Interest percentage	[1]	5.30%		5.30%
Due date	[1]	Jun. 1, 2042
3.750% Fixed Senior Notes due April 1, 2045 [Member]
Debt Instrument [Line Items]
Fixed Senior Note		$ 550		$ 375		$ 375
Interest percentage		3.75%		3.75%		3.75%
Due date		Apr. 1, 2045
Bondco [Member]
Debt Instrument [Line Items]
Fixed Bonds	[2]			$ 41
Less amount due currently	[2]			(41)
Bondco [Member] | 5.290% Fixed Series 2004 Bonds Due May 15, 2016 [Member]
Debt Instrument [Line Items]
Fixed Bonds	[2]			$ 41
Interest percentage	[2]	5.29%		5.29%
Due date	[2]	May 15, 2016
[1]	Secured by first priority lien on certain transmission and distribution assets equally and ratably with all of Oncor's other secured indebtedness. See "Deed of Trust" below for additional information.
[2]	The transition bonds were nonrecourse to Oncor and were issued to securitize a regulatory asset.

Long-Term Debt (Schedule Of L44

Long-Term Debt (Schedule Of Long-Term Debt Maturity) (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015
Long-Term Debt [Abstract]
2,017		$ 324
2,018		550
2,019		250
2,020		126
Thereafter		4,625
Unamortized discount and debt issuance costs	[1]	(36)	$ (54)
Total		$ 5,839	$ 5,687
[1]	Secured by first priority lien on certain transmission and distribution assets equally and ratably with all of Oncor's other secured indebtedness. See "Deed of Trust" below for additional information.

Commitments And Contingencies45

Commitments And Contingencies (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments and Contingencies [Abstract]
Rent expenses	$ 9	$ 8	$ 9
2017 required efficiency spending amount	$ 49
Percentage of full time employees represented by labor union	19.00%
Expiration date of collective bargaining agreement	Oct. 25, 2017

Commitments And Contingencies46

Commitments And Contingencies (Schedule Of Future Miinimum Lease Payments Under Operating Leases) (Details) $ in Millions	Dec. 31, 2016USD ($)
Commitments and Contingencies [Abstract]
2,017	$ 6
2,018	1
2,019	1
Total future minimum lease payments	$ 8

Membership Interests (Narrative

Membership Interests (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Membership Interests [Abstract]
Assumed debt to equity ratio, debt	60.00%
Assumed debt to equity ratio, equity	40.00%
Cash available for distribution under the capital structure restriction	$ 103
Regulatory capitalization ratio, debt	59.40%
Regulatory capitalization ratio, equity	40.60%
Cash distribution to members	$ 230	$ 436	$ 282

Membership Interests (Schedule

Membership Interests (Schedule Of Distributions Paid) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Dividends Payable [Line Items]
Amount	$ 230	$ 436	$ 282
Payment One FY 2016 [Member]
Dividends Payable [Line Items]
Declaration Date	Oct. 26, 2016
Payment Date	Oct. 27, 2016
Amount	$ 41
Payment Two FY 2016 [Member]
Dividends Payable [Line Items]
Declaration Date	Jul. 27, 2016
Payment Date	Aug. 11, 2016
Amount	$ 68
Payment Three FY 2016 [Member]
Dividends Payable [Line Items]
Declaration Date	Apr. 27, 2016
Payment Date	May 11, 2016
Amount	$ 65
Payment Four FY 2016 [Member]
Dividends Payable [Line Items]
Declaration Date	Feb. 24, 2016
Payment Date	Feb. 25, 2016
Amount	$ 56
Payment One FY 2015 [Member]
Dividends Payable [Line Items]
Declaration Date		Dec. 9, 2015
Payment Date		Dec. 11, 2015
Amount		$ 18
Payment Two FY 2015 [Member]
Dividends Payable [Line Items]
Declaration Date		Oct. 27, 2015
Payment Date		Nov. 9, 2015
Amount		$ 135
Payment Three FY 2015 [Member]
Dividends Payable [Line Items]
Declaration Date		Jul. 29, 2015
Payment Date		Aug. 10, 2015
Amount		$ 118
Payment Four FY 2015 [Member]
Dividends Payable [Line Items]
Declaration Date		Apr. 29, 2015
Payment Date		May 15, 2015
Amount		$ 65
Payment Five FY 2015 [Member]
Dividends Payable [Line Items]
Declaration Date		Feb. 25, 2015
Payment Date		Feb. 26, 2015
Amount		$ 100

Membership Interests (Schedul49

Membership Interests (Schedule Of Changes To Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (113)	$ (107)	$ (48)
Balance at end of period	(111)	(113)	(107)
Cash Flow Hedges - Interest Rate Swap [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(22)	(24)	(26)
Defined benefit pension plans (net of tax)
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges	2	2	2
Balance at end of period	(20)	(22)	(24)
Defined Benefit Pension and OPEB Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(91)	(83)	(22)
Defined benefit pension plans (net of tax)		(8)	(61)
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges
Balance at end of period	(91)	(91)	(83)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(113)	(107)	(48)
Defined benefit pension plans (net of tax)		(8)	(61)
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges	2	2	2
Balance at end of period	$ (111)	$ (113)	$ (107)

Pension And OPEB Plans (Narrati

Pension And OPEB Plans (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)item	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets		$ 1,974	$ 1,958
Earning period		3 years
Rolling period		4 years
Percentage of gains and losses		25.00%
Second pool representation of total investments, percentage		34.00%
Cash contributions		$ 35	79	$ 86
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service costs	$ 0
EFH Thrift Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash contributions		$ 15	14	13
Oncor Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of corporate bonds | item		1,217
Pension And OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets		$ 1,199	1,182
Vistra Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Unfunded liability		(85)
Defined Benefit Pension Plans [Member] | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of net actuarial loss	46
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Unfunded liability		(1,020)	(949)
Amortization of net actuarial loss		(41)	(63)	(39)
Expected funding, 2017		149
Expected funding, 2017 to 2021		586
Cash contributions		$ 4	$ 54	$ 68
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of corporate bonds | item		489
Expected funding, 2017		$ 31
Expected funding, 2017 to 2021		$ 153
OPEB Plan [Member] | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of net actuarial loss	32
Amortization of prior service costs	$ 20
Oncor Cash Balance Formula Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of employee's contribution match by employer		100.00%
Percentage of employee's contribution matched 100% by employer		6.00%
Oncor Traditional Retirement Plan Formula Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of employee's contribution match by employer		75.00%
Percentage of employee's contribution matched 100% by employer		6.00%

Pension And OPEB Plans (Schedul

Pension And OPEB Plans (Schedule Of Pension And OPEB Plan Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Total benefit costs	$ 138	$ 157	$ 106
Less amounts recognized principally as property or a regulatory asset	(100)	(113)	(69)
Net amounts recognized as expense	38	44	37
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total benefit costs	76	104	58
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total benefit costs	$ 62	$ 53	$ 48

Pension And OPEB Plans (Sched52

Pension And OPEB Plans (Schedule Of Detailed Pension And OPEB Benefit Information) (Details) - USD ($) $ in Millions		6 Months Ended		12 Months Ended
		Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assumptions Used to Determine Net Periodic Pension and OPEB Costs:
Discount rate		4.39%	4.98%
Components of Net Pension and OPEB Costs:
Net costs				$ 138	$ 157	$ 106
Pension Plan [Member]
Assumptions Used to Determine Net Periodic Pension and OPEB Costs:
Discount rate	[1]			4.30%	3.96%	4.74%
Expected return on plan assets				5.54%	5.26%	6.47%
Rate of compensation increase				3.29%	3.29%	3.94%
Components of Net Pension and OPEB Costs:
Service cost				$ 23	$ 25	$ 23
Interest cost				134	131	132
Expected return on assets				(122)	(115)	(136)
Amortization of net loss				41	63	39
Net costs				76	104	58
Other Changes in Plan Assets and Benefit Obligations Recognized as Regulatory Assets or in Other Comprehensive Income:
Net loss (gain)				41	37	388
Amortization of net loss				(41)	(63)	(39)
Total recognized as regulatory assets or other comprehensive income					(26)	349
Total recognized in net periodic pension and OPEB costs and as regulatory assets or other comprehensive income				$ 76	$ 78	$ 407
OPEB [Member]
Assumptions Used to Determine Net Periodic Pension and OPEB Costs:
Discount rate	[1]			4.60%	4.23%	4.98%
Expected return on plan assets				6.30%	6.65%	7.05%
Components of Net Pension and OPEB Costs:
Service cost				$ 7	$ 7	$ 6
Interest cost				49	43	44
Expected return on assets				(9)	(10)	(12)
Amortization of prior service cost (credit)				(20)	(20)	(20)
Amortization of net loss				35	33	30
Net costs				62	53	48
Other Changes in Plan Assets and Benefit Obligations Recognized as Regulatory Assets or in Other Comprehensive Income:
Net loss (gain)				10	39	128
Amortization of net loss				(35)	(33)	(30)
Amortization of prior service cost (credit)				20	20	20
Total recognized as regulatory assets or other comprehensive income				(5)	26	118
Total recognized in net periodic pension and OPEB costs and as regulatory assets or other comprehensive income				$ 57	$ 79	$ 166
[1]	As a result of the transfer of OPEB plan assets and liabilities from the EFH OPEB Plan to the Oncor OPEB Plan discussed above, the discount rate reflected in OPEB costs for January through June 2014 was 4.98% and for July through December 2014 was 4.39%.

Pension And OPEB Plans (Assumpt

Pension And OPEB Plans (Assumptions Used To Determine Benefit Obligations) (Details)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.05%	4.30%	3.96%
Rate of compensation increase	3.33%	3.29%	3.29%
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.35%	4.60%	4.23%

Pension And OPEB Plans (Change

Pension And OPEB Plans (Change In Project Benefit Obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at beginning of year	$ 3,201	$ 3,379
Service cost	23	25	$ 23
Interest cost	134	131	132
Participant contributions
Assumption of liabilities
Actuarial (gain) loss	106	(181)
Benefits paid	(157)	(153)
Projected benefit obligation at end of year	3,307	3,201	3,379
Accumulated benefit obligation at end of year	3,213	3,100
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at beginning of year	1,088	1,054
Service cost	7	7	6
Interest cost	49	43	44
Participant contributions	17	15
Assumption of liabilities	7
Actuarial (gain) loss	10	25
Benefits paid	(62)	(56)
Projected benefit obligation at end of year	1,116	1,088	$ 1,054
Accumulated benefit obligation at end of year

Pension And OPEB Plans (Chang55

Pension And OPEB Plans (Change In Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 35		$ 79		$ 86
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of assets at beginning of year	2,252	[1]	2,454
Actual return (loss) on assets	188		(103)
Employer contributions	4		54		68
Assets related to assumed liabilies
Participant contributions
Benefits paid	(157)		(153)
Fair value of assets at end of year	2,287		2,252	[1]	2,454
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of assets at beginning of year	141	[1]	161
Actual return (loss) on assets	9		(4)
Employer contributions	31		25		18
Assets related to assumed liabilies	7
Participant contributions	17		15
Benefits paid	(62)		(56)
Fair value of assets at end of year	$ 143		$ 141	[1]	$ 161
[1]	2015 presentation has been revised to reflect the application of ASU 2015-07 consistent with 2016 (see Note 1).

Pension And OPEB Plans (Funded

Pension And OPEB Plans (Funded Status) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$ (3,307)	$ (3,201)		$ (3,379)
Fair value of assets at end of year	2,287	2,252	[1]	2,454
Funded status at end of year	(1,020)	(949)
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	(1,116)	(1,088)		(1,054)
Fair value of assets at end of year	143	141	[1]	$ 161
Funded status at end of year	$ (973)	$ (947)
[1]	2015 presentation has been revised to reflect the application of ASU 2015-07 consistent with 2016 (see Note 1).

Pension And OPEB Plans (Amounts

Pension And OPEB Plans (Amounts Recognized In Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive net loss	$ (111)	$ (113)	$ (107)	$ (48)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other current liabilities	(4)	(4)
Other noncurrent liabilities	(1,016)	(945)
Net liability recognized	(1,020)	(949)
Net loss	583	583
Net regulatory asset recognized	583	583
Accumulated other comprehensive net loss	136	136
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Other noncurrent liabilities	(973)	(947)
Net liability recognized	(973)	(947)
Net loss	296	320
Prior service cost (credit)	(30)	(50)
Net regulatory asset recognized	266	270
Accumulated other comprehensive net loss	$ 4	$ 4

Pension And OPEB Plans (Sched58

Pension And OPEB Plans (Schedule Of Assumed Health Care Cost Trend Rates) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Effect on accumulated postretirement obligation, 1-Percentage Point Increase	$ 152
Effect on accumulated postretirement obligation, 1-Percentage Point Decrease		$ (125)
Effect on postretirement benefits cost, 1-Percentage Point Increase	$ 8
Effect on postretirement benefits cost, 1-Percentage Point Decrease		$ (7)
Not Medicare Eligible [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year	5.80%	6.00%
Rate to which the cost trend is expected to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2,024	2,024
Medicare Eligible [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate assumed for next year	5.70%	5.80%
Rate to which the cost trend is expected to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2,024	2,024

Pension And OPEB Plans (Sched59

Pension And OPEB Plans (Schedule Of Projected Benefit Obligations And Accumulated Benefit Obligations In Excess Of Plan Assets Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Pension And OPEB Plans [Abstract]
Projected benefit obligations	$ 3,137	$ 3,035
Accumulated benefit obligations	3,051	2,944
Plan assets	$ 2,112	$ 2,085

Pension And OPEB Plans (Sched60

Pension And OPEB Plans (Schedule Of Target Asset Allocation Ranges By Asset Category) (Details)	12 Months Ended
	Dec. 31, 2016
International Equities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, Recoverable	14.00%
Target asset allocation, Nonrecoverable	5.00%
International Equities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, Recoverable	18.00%
Target asset allocation, Nonrecoverable	9.00%
US Equities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, Recoverable	17.00%
Target asset allocation, Nonrecoverable	6.00%
US Equities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, Recoverable	21.00%
Target asset allocation, Nonrecoverable	10.00%
Real Estate [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, Recoverable	4.00%
Real Estate [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, Recoverable	5.00%
Credit Strategies [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, Recoverable	6.00%
Target asset allocation, Nonrecoverable	4.00%
Credit Strategies [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, Recoverable	8.00%
Target asset allocation, Nonrecoverable	6.00%
Fixed Income [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, Recoverable	48.00%
Target asset allocation, Nonrecoverable	76.00%
Fixed Income [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation, Recoverable	60.00%
Target asset allocation, Nonrecoverable	84.00%

Pension And OPEB Plans (Sched61

Pension And OPEB Plans (Schedule Of Assets Fair Value Measured On Recurring Basis) (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		$ 1,792	$ 1,824	[1]
Total assets measured at net asset value	[2]	495	428	[1]
Total fair value of plan assets		2,287	2,252	[1]	$ 2,454
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets measured at net asset value	[2]	14	6	[1]
Total fair value of plan assets		143	141	[1]	$ 161
OPEB [Member] | Accounting Standards Update 2015-07 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		129	135	[1]
US Equities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		196	209	[1]
US Equities [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		41	39	[1]
International Equities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		225	256	[1]
International Equities [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		28	25	[1]
Corporate Bond Securities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy	[3]	1,089	1,098	[1]
Corporate Bond Securities [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy	[3]	28	29	[1]
US Treasury Securities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		223	189	[1]
US Treasury Securities [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		2	1	[1]
Other [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy	[4]	40	46	[1]
Other [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy	[5]	28	36	[1]
Real Estate [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		5	5	[1]
Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		418	456	[1]
Fair Value, Inputs, Level 1 [Member] | OPEB [Member] | Accounting Standards Update 2015-07 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		99	103	[1]
Fair Value, Inputs, Level 1 [Member] | US Equities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		193	201	[1]
Fair Value, Inputs, Level 1 [Member] | US Equities [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		41	39	[1]
Fair Value, Inputs, Level 1 [Member] | International Equities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		225	255	[1]
Fair Value, Inputs, Level 1 [Member] | International Equities [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		28	25	[1]
Fair Value, Inputs, Level 1 [Member] | Other [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy	[5]	28	35	[1]
Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		1,369	1,363	[1]
Fair Value, Inputs, Level 2 [Member] | OPEB [Member] | Accounting Standards Update 2015-07 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		30	32	[1]
Fair Value, Inputs, Level 2 [Member] | US Equities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		3	8	[1]
Fair Value, Inputs, Level 2 [Member] | International Equities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy	[1]		1
Fair Value, Inputs, Level 2 [Member] | Corporate Bond Securities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy	[3]	1,089	1,098	[1]
Fair Value, Inputs, Level 2 [Member] | Corporate Bond Securities [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy	[3]	28	29	[1]
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		223	189	[1]
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		2	1	[1]
Fair Value, Inputs, Level 2 [Member] | Other [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy	[4]	40	46	[1]
Fair Value, Inputs, Level 2 [Member] | Other [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy	[1],[5]		1
Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		5	5	[1]
Fair Value, Inputs, Level 3 [Member] | Real Estate [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		5	5	[1]
Interest-bearing Cash [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		14	21	[1]
Interest-bearing Cash [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		2	5	[1]
Interest-bearing Cash [Member] | Fair Value, Inputs, Level 1 [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		2	4	[1]
Interest-bearing Cash [Member] | Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy		$ 14	21	[1]
Interest-bearing Cash [Member] | Fair Value, Inputs, Level 2 [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total assets in the fair value hierarchy	[1]		$ 1
[1]	2015 presentation has been revised to reflect the application of ASU 2015-07 consistent with 2016 (see Note 1).
[2]	Fair value was measured using the net asset value (NAV) per share as a practical expedient as the investments did not have a readily determinable fair value and are not required to be classified in the fair value hierarchy. The NAV fair value amounts presented here are intended to permit a reconciliation to the total fair value of plan assets.
[3]	Substantially all corporate bonds are rated investment grade by a major ratings agency such as Moody's.
[4]	Other consists primarily of municipal bonds, emerging market debt, bank loans and fixed income derivative instruments.
[5]	Other consists primarily of diversified bond mutual funds.

Pension And OPEB Plans (Sched62

Pension And OPEB Plans (Schedule Of Expected Long-Term Rate Of Return On Assets Assumptions) (Details)	12 Months Ended
	Dec. 31, 2016
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	5.46%	[1]
Pension Plan [Member] | International Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	6.98%
Pension Plan [Member] | US Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	6.40%
Pension Plan [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	5.00%
Pension Plan [Member] | Credit Strategies [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	5.22%
Pension Plan [Member] | Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	4.50%
Pension Plan [Member] | Oncor Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	4.62%
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	6.10%
OPEB [Member] | 401(h) Accounts [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	6.60%
OPEB [Member] | Life Insurance VEBA [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	6.01%
OPEB [Member] | Union VEBA [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	6.01%
OPEB [Member] | Non-union VEBA [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	2.20%
OPEB [Member] | Vistra Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	5.13%
[1]	The 2017 expected long-term rate of return for the nonregulated portion of the Oncor Retirement Plan is 4.62%

Pension And OPEB Plans (Sched63

Pension And OPEB Plans (Schedule Of Contributions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Total contributions	$ 35	$ 79	$ 86
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions	4	54	68
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions	$ 31	$ 25	$ 18

Pension And OPEB Plans (Sched64

Pension And OPEB Plans (Schedule Of Estimated Future Benefit Payments) (Details) $ in Millions	Dec. 31, 2016USD ($)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
2,017	$ 173
2,018	179
2,019	184
2,020	190
2,021	195
2022-26	1,032
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
2,017	52
2,018	55
2,019	57
2,020	60
2,021	63
2022-26	$ 338

Stock-Based Compensation (Detai

Stock-Based Compensation (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	0
SARs Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend accrual compensation expense	$ 11
SARs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized dividend accretion and interest	$ 1	$ 1	$ 1

Related-Party Transactions (Nar

Related-Party Transactions (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2015
Related Party Transaction [Line Items]
Revenues from electricity delivery fees			$ 715	$ 955	$ 971
Posted security amount			1,739
Vistra [Member]
Related Party Transaction [Line Items]
Revenues from electricity delivery fees			715	955	971
Posted security amount		$ 6	0	6
Vistra [Member]
Related Party Transaction [Line Items]
Trade accounts and other receivables from affiliates			0
EFH Corp [Member]
Related Party Transaction [Line Items]
Trade accounts and other receivables from affiliates		118		118
Administrative and services costs			1	17	32
Shared facilities expense			3	4	4
Shared facilities payments received			1	2	$ 2
Reimbursement payment amount	$ 1
Sponsor Group [Member]
Related Party Transaction [Line Items]
Equity in existing vendor						16.60%
Cash payments to vendors		128	188
Trade payables related parties		$ 3	5	$ 3
Sponsor Group [Member] | Capitalized [Member]
Related Party Transaction [Line Items]
Cash payments to vendors			180
Sponsor Group [Member] | Operating And Maintenance Expense [Member]
Related Party Transaction [Line Items]
Cash payments to vendors			$ 8

Related-Party Transactions (Sch

Related-Party Transactions (Schedule Of Trade Accounts And Other Receivables From Related Parties) (Details) - EFH Corp [Member] $ in Millions	Dec. 31, 2015USD ($)
Related Party Transaction [Line Items]
Trade accounts and other receivables from affiliates	$ 120
Trade accounts and other payables to affiliates	(2)
Trade accounts and other receivables from affiliates - net	$ 118

Related-Party Transactions (S68

Related-Party Transactions (Schedule Of Amounts Payable To (Receivable From) Members In Lieu Of Income Taxes) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Federal income taxes receivable	$ (80)	$ (136)
Texas margin taxes payable	20	20
Net payable (receivable)	(60)	(116)
EFH Corp [Member]
Related Party Transaction [Line Items]
Federal income taxes receivable	(62)	(109)
Texas margin taxes payable	20	20
Net payable (receivable)	(42)	(89)
Texas Transmission Investment LLC [Member]
Related Party Transaction [Line Items]
Federal income taxes receivable	(18)	(27)
Net payable (receivable)	$ (18)	$ (27)

Related-Party Transactions (Cas

Related-Party Transactions (Cash Payments Made To (Received From) Members In Lieu Of Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Federal income taxes		$ 135	$ 269
Texas margin taxes	$ 20	24	22
Total payments (receipts)	20	159	291
EFH Corp [Member]
Related Party Transaction [Line Items]
Federal income taxes		108	215
Texas margin taxes	20	24	22
Total payments (receipts)	$ 20	132	237
Texas Transmission Investment LLC [Member]
Related Party Transaction [Line Items]
Federal income taxes		27	54
Total payments (receipts)		$ 27	$ 54

Supplementary Financial Infor70

Supplementary Financial Information (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended			24 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2004	Dec. 31, 2003
Supplemental Financial Information [Line Items]
Restricted cash	$ 0	$ 38		$ 0
Face value of life insurance policies	153	$ 155		153
Net cash surrender values	$ 76			76
Depreciation expense as percentage of average depreciable property	3.50%	3.60%	3.60%
Aggregate amortization expenses	$ 61	$ 64	$ 58
Goodwill	$ 4,064	$ 4,064		4,064
Bondco [Member]
Supplemental Financial Information [Line Items]
Principal amount of transition bonds issued					$ 1,300	$ 1,300
Financial support				$ 0
Sales [Member] | Vistra [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage	23.00%	25.00%	25.00%
Sales [Member] | Vistra [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage	23.00%	25.00%	25.00%
Sales [Member] | Nonaffiliated REP [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage	17.00%	17.00%	16.00%
Nonaffiliated Trade Accounts Receivable [Member] | Vistra [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage	15.00%
Nonaffiliated Trade Accounts Receivable [Member] | Nonaffiliated REP [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage	12.00%	13.00%
Land Easements [Member]
Supplemental Financial Information [Line Items]
Weighted average remaining useful life	84 years
Capitalized Software [Member]
Supplemental Financial Information [Line Items]
Weighted average remaining useful life	3 years

Supplementary Financial Infor71

Supplementary Financial Information (Schedule Of Other Income And (Deductions)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplementary Financial Information [Abstract]
Accretion of fair value adjustment (discount) to regulatory assets due to purchase accounting	$ 1	$ 5	$ 12
Professional fees	(15)	(19)	(14)
Non-recoverable pension and OPEB (Note 9)	(2)	(9)	(1)
Interest Income	2		3
Other	(1)
Other		1	1
Total other income and (deductions) - net	$ (15)	$ (22)	$ 1

Supplementary Financial Infor72

Supplementary Financial Information (Schedule Of Interest Expense And Related Charges) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplementary Financial Information [Abstract]
Interest	$ 341	$ 335	$ 355
Amortization of debt issuance costs and discounts	3	3	3
Less allowance for funds used during construction — capitalized interest portion	(8)	(5)	(5)
Total interest expense and related charges	$ 336	$ 333	$ 353

Supplementary Financial Infor73

Supplementary Financial Information (Schedule Of Restricted Cash) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash - Current Assets	$ 0	$ 38
Customer Collections Related To Transition Bonds Used Only To Service Debt And Pay Expenses [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash - Current Assets		22
Reserve For Fees Associated With Transition Bonds [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash - Current Assets		10
Reserve For Shortfalls Of Transition Bond Charges [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Total restricted cash - Current Assets		$ 6

Supplementary Financial Infor74

Supplementary Financial Information (Schedule Of Trade Accounts And Other Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Supplementary Financial Information [Abstract]
Gross trade accounts and other receivables	$ 548	$ 509
Trade accounts and other receivables from TCEH (affiliated)		(118)
Allowance for uncollectible accounts	(3)	(3)
Trade accounts receivable from nonaffiliates - net	$ 545	$ 388

Supplementary Financial Infor75

Supplementary Financial Information (Summary of Investments And Other Property) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Supplementary Financial Information [Abstract]
Assets related to employee benefit plans, including employee savings programs	$ 98	$ 94
Land	2	3
Total investments and other property	$ 100	$ 97

Supplementary Financial Infor76

Supplementary Financial Information (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Property Plant and Equipment [Line Items]
Total assets in service	$ 20,234	$ 19,072
Less accumulated depreciation	6,836	6,479
Net of accumulated depreciation	13,398	12,593
Construction work in progress	416	416
Held for future use	15	15
Property, plant and equipment - net	13,829	13,024
Distribution [Member]
Property Plant and Equipment [Line Items]
Total assets in service	$ 11,369	10,861
Composite depreciation rate	3.90%
Avg. life	25 years 6 months
Transmission [Member]
Property Plant and Equipment [Line Items]
Total assets in service	$ 7,734	7,209
Composite depreciation rate	2.80%
Avg. life	35 years 2 months 12 days
Other Assets [Member]
Property Plant and Equipment [Line Items]
Total assets in service	$ 1,131	$ 1,002
Composite depreciation rate	9.00%
Avg. life	11 years 1 month 6 days

Supplementary Financial Infor77

Supplementary Financial Information (Schedule Of Intangible Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 961	$ 902
Accumulated Amortization	420	360
Net	541	542
Land Easements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	491	467
Accumulated Amortization	94	91
Net	397	376
Capitalized Software [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	470	435
Accumulated Amortization	326	269
Net	$ 144	$ 166

Supplementary Financial Infor78

Supplementary Financial Information (Schedule Of Estimated Aggregate Amortization Expenses) (Details) $ in Millions	Dec. 31, 2016USD ($)
Supplementary Financial Information [Abstract]
2,017	$ 56
2,018	50
2,019	47
2,020	46
2,021	$ 46

Supplementary Financial Infor79

Supplementary Financial Information (Schedule Of Employee Benefit Obligations And Other) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Supplementary Financial Information [Abstract]
Retirement plans and other employee benefits	$ 2,092	$ 1,985
Uncertain tax positions (including accrued interest)	3	3
Amounts payable related to income taxes
Investment tax credits	12	15
Other	61	60
Total other noncurrent liabilities and deferred credits	$ 2,168	$ 2,063

Supplementary Financial Infor80

Supplementary Financial Information (Schedule Of Supplemental Cash Flow Information) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplementary Financial Information [Abstract]
Interest		$ 336	$ 346	$ 356
Less capitalized interest		(8)	(5)	(5)
Interest payments (net of amounts capitalized)		328	341	351
Federal			135	269
State		20	43	22
Total amount in lieu of income taxes		20	178	291
Noncash construction expenditures	[1]	$ 122	$ 56	$ 82
[1]	Represents end-of-period accruals.

Supplementary Financial Infor81

Supplementary Financial Information (Schedule Of Quarterly Information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplementary Financial Information [Abstract]
Operating revenues	$ 958	$ 1,071	$ 948	$ 943	$ 922	$ 1,072	$ 938	$ 946	$ 3,920	$ 3,878	$ 3,822
Operating income	162	250	196	169	160	253	186	180	777	779	800
Net income	$ 77	$ 163	$ 110	$ 81	$ 73	$ 163	$ 98	$ 98	$ 431	$ 432	$ 450