Oncor Electric Delivery 10-Q 27 Oct 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 26, 2017
Entity Registrant Name	ONCOR ELECTRIC DELIVERY CO LLC
Entity Central Index Key	1,193,311
Document Type	10-Q
Document Period End Date	Sep. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		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%

Condensed Statements Of Consoli

Condensed Statements Of Consolidated Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating revenues:
Nonaffiliates	$ 1,068	$ 806	$ 2,967	$ 2,262
Affiliates		265		700
Total operating revenues	1,068	1,071	2,967	2,962
Operating expenses:
Wholesale transmission service	230	224	690	663
Operation and maintenance (Note 10)	184	190	552	542
Depreciation and amortization	193	190	581	593
Provision in lieu of income taxes (Note 10)	94	99	200	211
Taxes other than amounts related to income taxes	120	118	340	338
Total operating expenses	821	821	2,363	2,347
Operating income	247	250	604	615
Other income and (deductions) - net (Note 11)	(5)	(3)	(12)	(11)
Nonoperating provision in lieu of income taxes	(2)	(1)	(8)	(3)
Interest expense and related charges (Note 11)	87	85	257	252
Net income	$ 157	$ 163	$ 343	$ 355

Condensed Statements Of Consol3

Condensed Statements Of Consolidated Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Condensed Statements Of Consolidated Comprehensive Income [Abstract]
Net income	$ 157	$ 163	$ 343	$ 355
Other comprehensive income (loss):
Cash flow hedges – derivative value net loss recognized in net income (net of tax expense of $–, $–, $– and $–)		1	1	1
Defined benefit pension plans (net of tax benefit of $–, $-, $1 and $-)	1		2	1
Total other comprehensive income	1	1	3	2
Comprehensive income	$ 158	$ 164	$ 346	$ 357

Condensed Statements Of Consol4

Condensed Statements Of Consolidated Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Condensed Statements Of Consolidated Comprehensive Income [Abstract]
Cash flow hedges - derivative value net loss recognized in net income, tax expense
Defined benefit pension plans- net tax benefit			$ 1

Condensed Statements Of Consol5

Condensed Statements Of Consolidated Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows - operating activities:
Net income	$ 343	$ 355
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	618	629
Provision in lieu of deferred income taxes - net	250	166
Other - net	(2)	(3)
Changes in operating assets and liabilities:
Regulatory accounts related to reconcilable tariffs (Note 4)	30	(60)
Other operating assets and liabilities	(189)	(127)
Cash provided by operating activities	1,050	960
Cash flows - financing activities:
Issuances of long-term debt (Note 6)	600	175
Repayments of long-term debt (Note 6)	(324)	(41)
Net increase in short-term borrowings (Note 5)	128	40
Distributions to members (Note 8)	(237)	(189)
Debt discount, premium, financing and reacquisition costs - net	(4)	11
Cash provided by (used in) financing activities	163	(4)
Cash flows - investing activities:
Capital expenditures (Note 10)	(1,234)	(1,004)
Other - net	10	47
Cash used in investing activities	(1,224)	(957)
Net change in cash and cash equivalents	(11)	(1)
Cash and cash equivalents - beginning balance	16	25
Cash and cash equivalents - ending balance	$ 5	$ 24

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 5	$ 16
Trade accounts receivable - net (Note 11)	634	545
Amounts receivable from members related to income taxes (Note 10)	37	80
Materials and supplies inventories - at average cost	92	89
Prepayments and other current assets	97	100
Total current assets	865	830
Investments and other property (Note 11)	109	100
Property, plant and equipment - net (Note 11)	14,587	13,829
Goodwill (Note 11)	4,064	4,064
Regulatory assets (Note 4)	1,967	1,974
Other noncurrent assets	16	14
Total assets	21,608	20,811
Current liabilities:
Short-term borrowings (Note 5)	917	789
Long-term debt due currently (Note 6)	550	324
Trade accounts payable (Note 10)	216	231
Amounts payable to members related to income taxes (Note 10)	16	20
Accrued taxes other than amounts related to income	156	182
Accrued interest	85	83
Other current liabilities	158	144
Total current liabilities	2,098	1,773
Long-term debt, less amounts due currently (Note 6)	5,566	5,515
Liability in lieu of deferred income taxes (Note 10)	3,042	2,788
Regulatory liabilities - (Note 4)	1,009	856
Employee benefit obligations and other (Note 10 and 11)	2,073	2,168
Total liabilities	13,788	13,100
Commitments and contingencies (Note 7)
Membership interests (Note 8):
Capital account — number of interests outstanding 2017 and 2016 - 635,000,000	7,928	7,822
Accumulated other comprehensive loss	(108)	(111)
Total membership interests	7,820	7,711
Total liabilities and membership interests	21,608	20,811
Bondco [Member]
Current liabilities:
Long-term debt due currently (Note 6)	$ 550	$ 324

Condensed Consolidated Balance7

Condensed Consolidated Balance Sheets (Parenthetical) - shares	Sep. 30, 2017	Dec. 31, 2016
Condensed Consolidated Balance Sheets [Abstract]
Capital account, interests outstanding	635,000,000	635,000,000

Business and Significant Accoun

Business and Significant Accounting Policies	9 Months Ended
	Sep. 30, 2017
Business And Significant Accounting Policies [Abstract]
BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES	1. 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 (subsidiaries of TCEH until October 3, 2016) represented 23% and 24% of our total operating revenues for the nine month s ended September 30, 2017 and 2016 , 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 variable interest entity through December 29, 2016, at which time it was dissolved. 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.  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 not 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 Corp. Bankruptcy Proceedings  On the EFH Petition Date, the Debtors 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  These unaudited condensed financial statements should be read in conjunction with the audited financial statements and related notes included in the 2016 Form 10-K. In the opinion of Oncor management, all adjustments (consisting of normal recurring accruals) necessary for a fair presentation of the results of operations and financial position have been made. All intercompany items and transactions have been eliminated in consolidation. The results of operations for an interim period may not give a true indication of results for a full year due to seasonality. 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.  Revenue Recognition  General  Oncor’s revenue 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.  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.  Changes in Accounting Standards  In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-2 which created FASB Topic 842, Leases (Topic 842) . Topic 84 2 amends previous GAAP to require the balance sheet recognition of lease assets and liabilities for operating leases. Operating lease liabilities will not be classified as debt for GAAP purposes under Topic 842 and will not be treated as debt for regulatory purposes. At this time, all of Oncor’s existing leases meet the definition of an operating lease liability . Under the new rules, the recognition of any finance leases (currently known as capital leases) on the balance sheet would be classified as debt for GAAP purposes and are expected to be defined as debt for our regulatory capital structure purposes (see Note 8 for details) similar to the current capital lease treatment. We will be required to adopt Topic 842 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 initial adoption of Topic 842 will affect our balance sheet, as leased buildings and vehicles are recognized as operating lease liabilities. Subsequent to adoption, to the extent Oncor enters into f inance leases, its credit facility covenants and capitalization ratios could be impacted. We continue to evaluate the potential impact of Topic 842 on our financial statements.  Since May 2014, the FASB has issued ASU 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 are required to adopt Topic 606 by January 1, 2018 and expect to adopt at that time using the modified retrospective approach. 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 position or cash flows. We continue to evaluate the application of the new guidance.  In March 2017, the FASB issued ASU 2017-07 Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost , an amendment to Topic 715, Compensation – Retirement Benefits (Topic 715). Topic 715, as amended, will require the non-service cost components of net retirement benefit plan costs be presented as non-operating in the income statement. In addition, only the service cost component of net retirement benefit plan cost will be eligible for capitalization as part of inventory or property, plant and equipment. We are required to adopt the amendment effective January 1, 2018. The income statement presentation requirement must be applied on a retrospective basis while the capitalization eligibility requirement is applied on a prospective basis. For cash flow purposes on a prospective basis, non-service costs will be reflected as a reduction to operating cash flows, offset by lower cash used in investing activities (lower capital expenditures). At this time, we do not expect the new guidance to have a material effect on our rate-making process, our results of operations, financial position or net change in total cash flows but continue to evaluate for potential impacts.

EFH Bankruptcy Proceedings

EFH Bankruptcy Proceedings	9 Months Ended
	Sep. 30, 2017
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 September 30, 2017, we had collected our prepetition receivables from the Texas Holdings Group of approximately $129 million. As discussed below, the 2016 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 Spin-Off), Vistra and its subsidiaries, including Luminant and TXU Energy, ceased to be affiliates of ours as of October 3, 2016.  The EFH Bankruptcy Proceedings continue to be a complex litigation matter and the full extent of potential impacts on us remain unknown. Bankruptcy courts have broad equitable powers, and as a result, outcomes in bankruptcy proceedings are inherently difficult to predict. 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 10 for details of Oncor’s related-party transactions with members of the Texas Holdings Group.  Potential Change in Indirect Ownership of Oncor  Below is a summary of certain matters relating to the potential change in indirect ownership of Oncor that may arise as a result of the EFH Bankruptcy Proceedings. See Note 2 to Financial Statements in our 2016 Form 10-K for additional information regarding these matters.  In May 2016, the Debtors filed a joint Plan of Reorganization ( 2016 Plan of Reorganization) pursuant to Chapter 11 of the U.S. Bankruptcy Code and a related disclosure statement with the bankruptcy court. The 2016 Plan of Reorganization provided that the confirmation and effective date of the 2016 Plan of Reorganization with respect to the TCEH Debtors may occur separate from, and independent of, the confirmation and effective date of the 2016 Plan of Reorganization with respect to the EFH Debtors. In this regard, the bankruptcy court confirmed the 2016 Plan of Reorganization with respect to the TCEH Debtors in August 2016, and it became effective by its terms, and the Vistra Spin-Off occurred, effective October 3, 2016.  Prior Merger Agreements  The following merger agreements relating to a potential change in indirect ownership of Oncor were entered into in connection with the EFH Bankruptcy Proceedings. Each of these prior merger agreements has been terminated in accordance with their respective terms, except the TTI Merger Agreement (as defined below).  · In December 2015, the EFH Debtors filed their sixth amended plan of reorganization ( Sixth Amended Plan of Reorganization) and entered into a merger and purchase agreement (Hunt Merger Agreement) with an investor group consisting of certain unsecured creditors of TCEH and an affiliate of Hunt Consolidated, Inc., as well as certain other investors designated by Hunt Consolidated, Inc. (collectively, the Hunt Investor Group), that would have led to a significant change in the indirect equity ownership of Oncor . In September 2015, Oncor and the Hunt Investor Group filed a joint application with the PUCT seeking certain regulatory approvals with respect to the transactions contemplated by the Sixth Amended Plan of Reorganization. The PUCT issued an order conditionally approving the joint application in March 2016 and in April 2016 the Hunt Investor Group and certain intervenors filed motions for rehearing. As discussed under “Regulatory Matters Related to the EFH Bankruptcy Proceedings” below, in May 2016, the PUCT denied the motions for rehearing in PUCT Docket No. 45188 and the Hunt Merger Agreement was terminated, and in June 2016 the Hunt Investor Group filed a petition with the Travis County District Court seeking review of the order.  · Following the termination of the Hunt Merger Agreement, in July 2016, the EFH Debtors entered into a Plan Support Agreement (NEE Plan Support Agreement) with NextEra Energy, Inc. (NEE) to effect an agreed upon restructuring of the EFH Debtors pursuant to an amendment (NEE Amendment) to the 2016 Plan of Reorganization (as amended by the NEE Amendment and as subsequently amended, NEE Plan) and EFH Corp. and EFIH entered into an Agreement and Plan of Merger (NEE Merger Agreement) with NEE and EFH Merger Co., LLC, a wholly-owned subsidiary of NEE. Additionally, in October 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 bankruptcy court approved EFH Corp. and EFIH’s entry into the NEE Merger Agreement and the NEE Plan Support Agreement in September 2016 and confirmed the NEE Plan in February 2017. The consummation of the transactions contemplated by the NEE Plan, the NEE Merger Agreement and the TTI Merger Agreement was subject to various conditions precedent, including the approval of the PUCT. Oncor and NEE filed a joint application seeking certain regulatory approvals with respect to the NEE Merger Agreement and the TTI Merger Agreement in October 2016. The PUCT denied the application in April 2017, issued an order on rehearing in June 2017 and denied NEE’s second motion for rehearing in June 2017. Following these developments, on July 6, 2017, EFH and EFIH delivered a notice terminating the NEE Merger Agreement, which caused the NEE Plan to be null and void. As discussed under “Regulatory Matters Related to the EFH Bankruptcy Proceedings” below, on July 13, 2017, NEE filed a petition with the Travis County District Court seeking review of the PUCT order (PUCT NEE Plan Order). We cannot assess the impact of the termination of the NEE Merger Agreement on the results of the review or ultimate disposition of the PUCT NEE Plan Order, or any associated impacts of such termination and matters relating to the PUCT NEE Plan Order on the TTI Merger Agreement and the transactions contemplated thereby.  · Following the termination of the NEE Merger Agreement, on July 7, 2017, EFH Corp. and EFIH executed a merger agreement (BHE Merger Agreement) with Berkshire Hathaway Energy Company (BHE ) and certain of its subsidiaries. The BHE Merger Agreement provided for the acquisition by BHE of the 80.03% of Oncor’s membe rship interests owned indirectly by EFH Corp. and EFIH. In connection with the execution of the BHE Merger Agreement, on July 7, 2017, the EFH Debtors filed their joint plan of reorganization (BHE Plan) and a related disclosure statement. The EFH Debtors terminated the BHE Merger Agreement on August 21, 2017 in connection with their entry into the Sempra Merger Agreement (as defined below), which caused the BHE Plan to become null and void. Further, by order dated September 7, 2017, the bankruptcy court ordered that the BHE Merger Agreement was terminated and not approved.  For additional information regarding the transactions contemplated by the merger and purchase agreement with the Hunt Investor Group, the NEE Plan, the NEE Merger Agreement, the TTI Merger Agreement and the BHE Merger Agreement, see Notes 2 and 8 to Financial Statements in our 2016 Form 10-K and Notes 2 and 7 to Financial Statements in our Quarterly Reports.  Sempra Merger Agreement  On August 15, 2017, the EFH Debtors received an alternative proposal from Sempra Energy (Sempra) that largely followed the structure of the BHE Plan. Following negotiations, on August 21, 2017, EFH Corp. and EFIH entered into an Agreement and Plan of Merger (Sempra Merger Agreement) with Sempra and one of its wholly-owned subsidiaries (collectively, the Sempra Parties). Similar to the BHE Merger Agreement, the Sempra Merger Agreement does not impose any conditions on the EFH Debtors regarding TTI’s minority interest in Oncor. Accordingly, the Sempra Merger Agreement provides for the acquisition by Sempra of the 80.03% of Oncor’s membership interests owned indirectly by EFH Corp. and EFIH.  Following the execution and delivery of the Sempra Merger Agreement, EFIH requested, pursuant to the Sempra Merger Agreement, that Oncor Holdings and Oncor enter into a letter agreement (Sempra Letter Agreement) with the Sempra Parties. The Sempra Letter Agreement was executed on August 25, 2017 and sets forth certain rights and obligations of the Oncor Ring-Fenced Entities and the Sempra Parties to cooperate in the manner set forth therein with respect to initial steps to be taken in connection with the acquisition of Reorganized EFH and the other transactions described in the Sempra Merger Agreement. Pursuant to the terms of the Sempra Letter Agreement, the Oncor Ring-Fenced Entities are to conduct, in all material respects, their businesses in the ordinary course of business and materially consistent with the plan for 2017 and 2018 contained in Oncor’s long-range business plan. The Sempra Letter Agreement also provides that the Oncor Ring-Fenced Entities will cooperate with the Sempra Parties to prepare and file all necessary applications for governmental approvals of the transactions contemplated by the Sempra Merger Agreement, including PUCT and FERC approvals. The Sempra Letter Agreement is not intended to give the Sempra Parties, directly or indirectly, the right to control or direct the operations of any of the Oncor Ring-Fenced Entities.  In connection with the execution of the Sempra Merger Agreement, on September 5, 2017, the EFH Debtors filed an amended joint plan of reorganization (Sempra Plan) and a related disclosure statement (Sempra Disclosure Statement). On September 6, 2017, the bankruptcy court authorized the EFH Debtors’ entry into the Sempra Merger Agreement, approved the Sempra Disclosure Statement and authorized the EFH Debtors to solicit votes on the Sempra Plan. The Sempra Merger Agreement contemplates that Oncor and the Sempra Parties will file a joint application with the PUCT seeking certain regulatory approvals with respect to the transactions contemplated by the Sempra Plan, and that filing was made on October 5, 2017 in PUCT Docket No. 47675. The EFH Debtors have indicated that they will not seek bankruptcy court confirmation of the Sempra Plan unless and until the PUCT approves the transactions contemplated by the Sempra Plan.  We cannot predict the ultimate outcome of the EFH Bankruptcy Proceedings, including whether the transactions contemplated by the Sempra Plan, including the Sempra M erger Agreement , will (or when they will) close. There remain conditions and uncertainties relating to the Sempra Plan becoming effective and the consummation of the transactions contemplated by the Sempra Merger Agreement, including, without limitation, the ability to obtain required regulatory approvals from 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 the EFH Debtors ultimately will impact Oncor or what form any change in indirect ownership of Oncor may take. In this regard, we are unable to predict the ultimate impact of the termination of the NEE Merger Agreement and matters relating to the PUCT NEE Plan Order or the TTI Merger Agreement, including the ultimate disposition, if any, of Texas Transmission’s 19.75% equity stake in Oncor.  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 a plan of reorganization in the EFH Bankruptcy Proceedings. In March 2016, the PUCT issued an order conditionally approving the joint application. In April 2016, the Hunt Investor Group and certain interveners in PUCT Docket No. 45188 filed motions for rehearing and in May 2016, the PUCT denied such motions and the order became final. In May 2016, the plan of reorganization and related merger and purchase agreement that contemplated the transactions in PUCT Docket No. 45188 were terminated. The Hunt Investor Group filed a petition with the Travis County District Court in June 2016 seeking review of the order. We cannot predict the results of the revie w or the ultimate disposition of PUCT Docket No. 45188, particularly in light of the termination of the Hunt Merger Agreement .  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 notified Oncor that they expected Oncor to make a rate filing to comply with their resolutions on or before March 17, 2017. That filing was made with the PUCT and original jurisdiction cities on March 17, 2017 in PUCT Docket No. 46957. In July 2017, we and certain parties to our rate review agreed to a settlement of that rate review, and on August 2, 2017 a settlement agreement was filed that settled all issues in the docket. On October 13, 2017, the PUCT issued an order approving the settlement agreement. For more information, see Note 3 – “2017 Rate Review (PUCT Docket No. 46957).”  The NEE Merger Agreement contemplated that Oncor and NEE file a joint application with the PUCT seeking certain regulatory approvals with respect to the transactions contemplated by the Amended EFH Debtor Plan. Oncor and NEE filed that joint application in PUCT Docket No. 46238 in October 2016. The PUCT denied the application on April 13, 2017. The PUCT issued an Order on Rehearing on June 7, 2017 and denied NEE’s Second Motion for Rehearing on June 29, 2017. On July 13, 2017, NEE filed a petition with the Travis County District Court seeking review of the PUCT order. We cannot predict the results of the review or the ultimate disposition of PUCT Docket No. 46238, particularly in light of the termination of the NEE Merger Agreement.  On July 28, 2017, Texas Transmission Holdings Corporation (TTHC) and NEE filed in PUCT Docket No. 47453 a joint application with the PUCT seeking certain regulatory approvals with respect to NEE’s proposed acquisition of the 19.75 percent minority interest in Oncor that is indirectly held by TTHC. The application request ed that the PUCT issue an order disclaiming jurisdiction over the transaction or finding that the transaction is in the public interest and approved. On September 14, 2017, Oncor filed a motion to intervene as a party, but not an applicant, in PUCT Docket No. 47453. On October 26, 2017, the PUCT voted to dismiss the application without prejudice on jurisdictional grounds and ordered that any future filing of the application must include the affected utility (in this case Oncor) as an applicant. The PUCT further ordered that in any such filing Oncor is not required to seek approval of the application or any other specific relief. We cannot predict the result of this proceeding.  Oncor and the Sempra Parties filed a joint application with the PUCT seeking certain regulatory approvals with respect to the transactions contemplated by the Sempra Plan on October 5, 2017 in PUCT Docket No. 47675.  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 ( i ) intercompany claims among the EFH Debtors, ( ii ) claims and causes of actions against holders of first lien claims against TCEH and the agents under the TCEH Senior Secured Facilities, ( iii ) claims and causes of action against holders of interests in EFH Corp. and certain related entities and ( iv ) 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	9 Months Ended
	Sep. 30, 2017
Regulatory Matters [Abstract]
REGULATORY MATTERS	3. REGULATORY MATTERS  Change in Control Reviews  See “Regulatory Matters Related to EFH Bankruptcy Proceedings” in Note 2 to Financials Statements.  2017 Rate Review (PUCT Docket No. 46957)  In response to resolutions passed by numerous cities with original jurisdiction over electric utility rates in 2016, we filed rate review proceedings with the PUCT and original jurisdiction cities in our service territory on March 17, 2017 based on a January 1, 2016 to December 31, 2016 test year. In July 2017, we and certain parties to our rate review agreed to a settlement of that rate review, and on August 2, 2017 a settlement agreement was filed that settled all issues in the docket. On October 13, 2017, the PUCT issued an order approving the settlement of the rate review. The order is expected to become final and non-appealable on November 7, 2017, after the time period for motions for rehearing expires. The order provides for new rates to take effect on November 27, 2017, contingent upon the closing of the transactions discussed below under “Sharyland Transaction.” If such transactions do not close on or before November 27, 2017, the PUCT order will be of no force and effect and Oncor and the parties to the rate review will work together to establish a new procedural schedule for the rate review. The order further provides, among other items, that Oncor’s base rate revenue requirement before intercompany eliminations would be approximately $4.3 billion, Oncor’s authorized return on equity would be 9.8% , and Oncor’s authorized regulatory capital structure would be 57.5% debt and 42.5% equity. Oncor’s current authorized return on equity is 10.25% and the current authorized regulatory capital structure is 60% debt and 40% equity. The PUCT order provides for the use of a regulatory liability and bill credit mechanism until the ne w authorized regulatory capital structure is met following the effective date for new rates to reflect our actual capitalization prior to achieving the authorized capital structure .  Sharyland Transaction  On July 21, 2017, we entered into an agreement (Sharyland A greement) with Sharyland Distribution & Transmission Services, L.L.C., a Texas limited liability company (SDTS), Sharyland Utilities, L.P., a Texas limited partnership (SU), and certain of their subsidiaries.  The Sharyland Agreement provides that pursuant to separate mergers (collectively, Sharyland Mergers), (i) we will receive certain of the electricity distribution-related assets and liabilities of SDTS and SU (constituting substantially all of the electricity distribution business of SDTS and SU) and certain transmission assets (collectively, Sharyland Distribution Business and the portion held by SDTS, the SDTS Merger Assets), (ii) SDTS will receive portions of certain of our electricity transmission-related assets and liabilities (Oncor Merger Assets) and cash, and (iii) SU will receive cash. The transaction for assets between Oncor and SDTS is structured to qualify, in part, as a simultaneous tax deferred like kind exchange of assets to the extent that the assets exchanged are of “like kind” (within the meaning of Section 1031 of the Internal Revenue Code).  The actual assets exchanged and cash received pursuant to the Sharyland Mergers is based on the difference between the current net book value of the Oncor Merger Assets and/or the actual net book value of the Sharyland Distribution Business as of closing, as provided in the Sharyland Agreement. The net book value of the Oncor Merger Assets is approximately $380 million and of the SDTS Merger Assets is approximately $401 million (each after taking into account working capital adjustments based on amounts as of the date of the Sharyland Agreement). Based on these net book values, we would owe SDTS approximately $20 million in cash and SU approximately $6.5 million in cash. While these amounts may change, Oncor does not expect its cash obligations to be material to it. Among other customary termination rights, the Sharyland Agreement may be terminated by SDTS, SU or Oncor, if the closing does not occur within 240 days after the date of the Sharyland Agreement .  On August 4, 2017, we, SDTS and SU filed a joint application for sale, transfer, or merger in PUCT Docket No. 47469 requesting PUCT approvals of the transactions contemplated by the Sharyland Agreement. On October 13, 2017, the PUCT issued an order approving the Sharyland Agreement in Docket No. 47469. All required PUCT approvals for the closing of the transactions contemplated by the Sharyland Agreement have now been received. The parties have also received clearance for the transactions contemplated by the Sharyland Agreement under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended. The court in the EFH Corp. and EFIH bankruptcy proceedings has also issued an order approving the consent by EFIH to Oncor’s entry into the Sharyland Agreement. Closing is also subject to the satisfaction of other customary closing conditions, including SDTS’s receipt of consent from the holders of certain of its indebtedness. We expect the transaction to close in the fourth quarter of 2017, before the November 27, 2017 effective date of the rate changes discussed above under “2017 Rate Review (PUCT Docket No. 46957).”  We do not expect the Sharyland transaction to have a material effect on our results of operations, financial position or cash flows.  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.  See Note 3 to Financial Statements in our 2016 Form 10-K for additional information regarding regulatory matters.

Regulatory Assets and Liabiliti

Regulatory Assets and Liabilities	9 Months Ended
	Sep. 30, 2017
Regulatory Assets and Liabilities [Abstract]
REGULATORY ASSETS AND LIABILITIES	4. REGULATORY ASSETS AND LIABILITIES  Recognition of regulatory assets and liabilities and the periods which they are to be recovered or refunded through rate regulation are determined by the PUCT. Components of our regulatory assets and liabilities and their remaining periods as of September 30, 2017 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  September 30, 2017 September 30, 2017 December 31, 2016   Regulatory assets:  Employee retirement costs being amortized 2 years $ 11 $ 23  Unrecovered employee retirement costs incurred since the last rate review period (b) To be determined 352 327  Employee retirement liability (a)(b)(c) To be determined 804 849  Self-insurance reserve (primarily storm recovery costs) being amortized 2 years 40 64  Unrecovered self-insurance reserve incurred since the last rate review period (b) To be determined 424 367  Securities reacquisition costs (post-industry restructure) Lives of related debt 12 13  Deferred conventional meter and metering facilities depreciation Largely 3 years 62 78  Under-recovered AMS costs To be determined 213 205  Energy efficiency performance bonus (a) 1 year or less 14 10  Other regulatory assets Various 35 38  Total regulatory assets 1,967 1,974   Regulatory liabilities:  Estimated net removal costs Lives of related assets 933 819  Investment tax credit and protected excess deferred taxes Various 9 10  Over-recovered wholesale transmission service expense (a) 1 year or less 46 10  Other regulatory liabilities Various 21 17  Total regulatory liabilities 1,009 856  Net regulatory assets $ 958 $ 1,118 ____________ (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. 

Short-Term Borrowings

Short-Term Borrowings	9 Months Ended
	Sep. 30, 2017
Short-Term Borrowings [Abstract]
SHORT-TERM BORROWINGS	5. SHORT-TERM BORROWINGS  At September 30, 2017 , 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 September 30, 2017 , we had outstanding borrowings under the revolving credit facility totaling $917 m ill ion with an interest rate of 2.22% and outstanding letters of credit totaling $9 million. At December 31, 2016 , 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.  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 September 30, 2017 , substantially all outstanding borrowings bore interest at LIBOR plus 1.00% . Amounts borrowed under the revolving credit facility, once repaid, can be borrowed 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 September 30, 2017 , 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 revolving credit facility, each based on our current credit ratings.  Subject to the limitations described below, borrowing capacity available under the revolving credit facility at September 30, 2017 and December 31, 2016 was $1.074 b illion and $1.204 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 6, the Deed of Trust permits us to secure indeb tedness (including borrowings under our revolving credit facility) with the lien of the Deed of Trust. At September 30, 2017 , 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). Capitalization is calculated as membership interests determined in accordance with GAAP plus indebtedness described above. At September 3 0 , 2017, we were in compli ance with this covenant and with all other covenants . 

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2017
Long-Term Debt [Abstract]
LONG-TERM DEBT	6. LONG-TERM DEBT  Our senior notes are secured by a 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. At September 30, 2017 and December 31, 2016, our long-term debt consisted of the following:   September 30, December 31,  2017 2016   Secured:  5.000% Fixed Senior Notes due September 30, 2017 $ - $ 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 550 550  3.800% Fixed Senior Notes due September 30, 2047 325 -  Secured long-term debt 5,876 5,875  Unsecured:  Term loan credit agreement due no later than March 26, 2019 275 -  Total long-term debt 6,151 5,875  Unamortized discount and debt issuance costs (35) (36)  Less amount due currently (550) (324)  Long-term debt, less amounts due currently $ 5,566 $ 5,515  Debt-Related Activity in 2017  Debt Repayments  Repayments of long-term debt in the nine months ended September 30, 2017 consisted of $324 million aggregate principal amount of 5.00% senior secured notes due September 30, 2017 (2017 Notes) that we redeemed on September 29, 2017.  Issuance of Senior Secured Notes  In September 2017, we issued $325 million aggregate principal amount of 3.80% senior secured notes due September 30, 2047 (2047 Notes). We used the proceeds (net of the initial purchasers’ discount, fees and expenses) of $321 million from the sale of the 2047 Notes for general corporate purposes, including repayment of borrowings under the revolving credit facility and payment of a portion of the redemption price for the 2017 Notes. The 2047 Notes are secured by a first priority lien, and are secured equally and ratably with all of our other secured indebtedness.  Interest on the 2047 Notes is payable in cash semiannually on March 30 and September 30 of each year, beginning on March 30, 2018. Prior to March 30, 2047, we may at our option at any time redeem all or part of the 2047 Notes at a price equal to 100% of their principal amount, plus accrued and unpaid interest and a make-whole premium. On and after March 30, 2047, Oncor may redeem the 2047 Notes at any time, in whole or in part, at a redemption price equal to 100% of the principal amount of such 2047 Notes, plus accrued and unpaid interest. The 2047 Notes also contain customary events of default, including failure to pay principal or interest on the Notes when due.  The 2047 Notes were issued in a private placement and were not registered under the Securities Act. We have agreed, subject to certain exceptions, to register with the SEC notes having substantially identical terms as the 2047 Notes (except for provisions relating to the transfer restriction and payment of additional interest) as part of an offer to exchange freely tradable exchange notes for the 2047 Notes. We have agreed to use commercially reasonable efforts to cause the exchange offer to be completed within 315 days after the issue date of the 2047 Notes. If a registration statement for the exchange offer is not declared effective by the SEC within 270 days after the issue date of the 2047 Notes or the exchange offer is not completed within 315 days after the issue date of the 2047 Notes (an exchange default), then the annual interest rate on the 2047 Notes will increase 50 basis points per annum until the earlier of the expiration of the exchange default or the second anniversary of the issue date of the Notes.  Term Loan Credit Agreement  On September 26, 2017, we entered into a term loan credit agreement that provides for a springing-lien term loan credit facility in an aggregate principal amount of $275 million. On December 31, 2017, if (i) the obligations under the term loan credit agreement are outstanding as of such date and (ii) the obligations under our revolving credit facility (as amended, restated, supplemented, refinanced, replaced or otherwise modified) are secured as of such date, then the obligations under the term loan credit agreement will become secured indebtedness under the lien of our Deed of Trust.  The term loan credit agreement has an 18 month term maturing on March 26, 2019, and contains optional prepayment provisions as well as mandatory prepayment provisions that require prepayment in the event of certain specified debt issuances or certain specified asset dispositions.  At September 30, 2017, we had outstanding borrowings of $275 million under the term loan credit agreement with an interest rate of 2.138%.  Loans under the term loan credit agreement bear interest at per annum rates equal to, at our option, (i) LIBOR plus a spread ranging from 0.80% - 0.90% , depending on whether the loan has become secured, or (ii) an alternate base rate (the highest of (1) the prime rate of Wells Fargo Bank, National Association, (2) the federal funds effective rate plus 0.50% , and (3) daily one-month LIBOR plus 1.00% ).  The term loan credit agreement 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 term loan credit agreement 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.  The term loan credit agreement also contains customary events of default for facilities of this type the occurrence of which would allow the lenders to accelerate all outstanding loans and terminate their commitments, including certain changes in control of Oncor that are not permitted transactions under the term loan credit agreement, cross-default provisions in the event Oncor or any of its subsidiaries defaults on indebtedness in a principal amount in excess of $100 million or receives judgments for the payment of money in excess of $50 million that are not discharged within 60 days.  Deed of Trust  Our secured indebtedness, including the revolving credit facility described in Note 5, 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 September 30, 2017 , the amount of available bond credits was $2.495 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 $2.109 billion.  Fair Value of Long-Term Debt  At September 30, 2017 and December 31, 2016 , the estimated fair value of our long-term debt (including current maturities, if any) totaled $7.093 billion and $6.751 billion, respectively, and the carrying amount totaled $6.116 billion and $5.839 b illion, 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	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies [Abstract]
COMMITMENTS AND CONTINGENCIES	7. COMMITMENTS AND CONTINGENCIES  EFH Bankruptcy Proceedings  On the EFH Petition Date, the Debtors commenced the EFH Bankruptcy Proceedings . T he Oncor Ring-Fenced Entities are not parties to the EFH Bankruptcy Proceedings. See Notes 2 and 10 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.  Sharyland Agreement  In July 2017, we entered into the Sharyland Agreement that involves the exchange of certain of our electricity transmission-related assets and liabilities for substantially all of Sharyland’s electricity distribution business and certain transmission assets as defined by the agreement. On October 13, 2017, the PUCT issued an order approving the transactions contemplated by the Sharyland Agreement. See Note 3 for additional information on and the status of the transaction.  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 in this report and Note 8 to Financial Statements in our 2016 Form 10-K for additional information regarding our legal and regulatory proceedings. 

Membership Interests

Membership Interests	9 Months Ended
	Sep. 30, 2017
Membership Interests [Abstract]
MEMBERSHIP INTERESTS	8. 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 was 60% debt to 40% equity as of September 30, 2017. 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. 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).  At September 30, 2017, $25 million was available for distribution to our members as our regulatory capitalization ratio was 59.9% debt to 40.1% equity. Our PUCT authorized capital structure will be 57.5% debt and 42.5% equity effective November 27, 2017 contingent upon the PUCT order issued in PUCT Docket No. 46957 becoming final and taking effect (see Note 3 for more details). To obtain the additional 2.5% equity capitalization, we anticipate that approximately $250 million of equity will be needed. The PUCT order in PUCT Docket No. 46957 provides for the use of a regulatory liability and bill credit mechanism until the new authorized regulatory capital structure is met following the effective date for new rates to reflect our actual capitalization prior to achieving the authorized capital structure.   On October 25, 2017, our board of directors declared a contingent cash distribution of $32 million to be paid to our members as of October 25, 2017 within one business day after an additional equity contribution is made to Oncor from members totaling approximately $250 million. In the event the additional equity contribution is not made on or before the date of the closing of the Sempra Merger Agreement, no distribution shall be payable. For more information on the Sempra Merger Agreement, see Note 2.  During the nine months ended September 30, 2017, our board of directors declared, and we paid, the following cash distributions to our members.    Declaration Date Payment Date Amount  July 26, 2017 August 1, 2017 $ 65  April 26, 2017 April 27, 2017 $ 86  March 22, 2017 March 24, 2017 $ 86  Membership Interests  The following table presents the changes to membership interests during the nine months ended September 30, 2017 and 2016:    Capital Accounts Accumulated Other Comprehensive Income (Loss) Total Membership Interests   Balance at December 31, 2016 $ 7,822 $ (111) $ 7,711  Net income 343 - 343  Distributions (237) - (237)  Net effects of cash flow hedges (net of tax) - 1 1  Defined benefit pension plans (net of tax) - 2 2  Balance at September 30, 2017 $ 7,928 $ (108) $ 7,820   Balance at December 31, 2015 $ 7,621 $ (113) $ 7,508  Net income 355 - 355  Distributions (189) - (189)  Net effects of cash flow hedges (net of tax) - 1 1  Defined benefit pension plans (net of tax) - 1 1  Balance at September 30, 2016 $ 7,787 $ (111) $ 7,676  Accumulated Other Comprehensive Income (Loss)  The following table presents the changes to accumulated other comprehensive income (loss) for the nine months ended September 30, 2017 and 2016:   Cash Flow Hedges – Interest Rate Swap Defined Benefit Pension and OPEB Plans Accumulated Other Comprehensive Income (Loss)   Balance at December 31, 2016 $ (20) $ (91) $ (111)  Defined benefit pension plans (net of tax) - 2 2  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 1 - 1  Balance at September 30, 2017 $ (19) $ (89) $ (108)   Balance at December 31, 2015 $ (22) $ (91) $ (113)  Defined benefit pension plans (net of tax) - 1 1  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 1 - 1  Balance at September 30, 2016 $ (21) $ (90) $ (111) 

Pension and OPEB Plans

Pension and OPEB Plans	9 Months Ended
	Sep. 30, 2017
Pension And OPEB Plans [Abstract]
PENSION AND OPEB PLANS	9. PENSION AND OPEB PLANS  Pension Plans  We sponsor the Oncor Retirement Plan and also have liabilities under the Vistra Retirement Plan , both of which are qualified pension plans under Section 401(a) of the Internal Revenue Code of 1986, as amended, and are subject to the provisions of ERISA. Employees do not contribute to either plan. We also have a supplemental pension plan for certain employees whose retirement benefits cannot be fully earned under the qualified retirement plans. See Note 10 to Financial Statements in our 2016 Form 10-K for additional information regarding pension plans.  Oncor OPEB Plan  The Oncor OPEB Plan covers our eligible current and future retirees as well as certain eligible retirees of EFH Corp. /Vistra whose employment service was assigned to both Oncor (or a predecessor regulated electric business) and a non-regulated business of EFH Corp. Vistra is solely responsible for its portion of the liability for retiree benefits related to those retirees. As we are not responsible for Vistra’s portion of the Oncor OPEB Plan’s unfunded liability, that amount is not reported on our balance sheet. See Note 10 to Financial Statements in our 2016 Form 10-K for additional information.  Pension and OPEB Costs  Our net costs related to pension plans and the Oncor OPEB P lan for the three and nine months ended September 30, 2017 and 2016 were comprised of the following:   Three Months Ended September 30, Nine Months Ended September 30,  2017 2016 2017 2016   Components of net allocated pension costs:  Service cost $ 6 $ 6 $ 18 $ 18  Interest cost 32 33 98 101  Expected return on assets (28) (30) (86) (92)  Amortization of net loss 11 10 33 30  Net pension costs 21 19 63 57  Components of net OPEB costs:  Service cost 1 2 5 6  Interest cost 12 12 36 36  Expected return on assets (2) (2) (6) (6)  Amortization of prior service cost (5) (5) (15) (15)  Amortization of net loss 8 9 24 26  Net OPEB costs 14 16 44 47  Total net pension and OPEB costs 35 35 107 104  Less amounts deferred principally as property or a regulatory asset (25) (25) (76) (75)  Net amounts recognized as expense $ 10 $ 10 $ 31 $ 29  The discount rates reflected in net pension and OPEB costs in 2017 are 4.04% , 4.28% and 4.35% for the Oncor Retirement Plan, the Vistra Retirement Plan and the Oncor OPEB Plan, respectively. The expected return on pension and OPEB plan assets reflected in the 2017 cost amounts are 5.17% , 5.13% and 6.10% for the Oncor Retirement Plan, the Vistra Retirement Plan and the Oncor OPEB Plan, respectively.  Pension and OPEB Plans Cash Contributions  We made cash contribution s to the pension plans and Oncor OPEB P lan of $128 million and $25 million, respectively, during the nine months ended September 30, 2017. We expect to make additional cash contributions to the pension plans and Oncor OPEB Plan of $21 million and $6 million, respectively, during the remainder of 201 7 . Our aggregate pension plans and Oncor OPEB Plan funding is expected to total approximately $564 million and $153 million, respectively, in the 201 7 to 202 1 period based on the latest actuarial projections.

Related-Party Transactions

Related-Party Transactions	9 Months Ended
	Sep. 30, 2017
Related-Party Transactions [Abstract]
RELATED-PARTY TRANSACTIONS	10. RELATED-PARTY TRANSACTIONS  The following represent our significant related-party transactions at September 30, 2017 . 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 $265 million and $700 million for the three and nine months ended September 30, 2016, respectively. The fees are based on rates regulated by th e PUCT that apply to all REPs.  · EFH Corp. subsidiaries charge d 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, tota l ed less than $1 million for each of the three - and nine-month periods ended September 30, 2016. We also charge d each other for shared facilities at cost. Our payments to EFH Corp. for shared facilities totaled $1 m i llion and $3 million for the three and nine month s ended September 30, 2016, respectively . Payments we received from EFH Corp. subsidiaries related to shared facilities totaled $1 m illion for each of the three - and nine- month periods ended September 30, 2016.  · 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, if any, 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 are accounted for as income taxes and calculated as if we were filing our own return. See discussion in Note 1 to Financial Statements in our 2016 Form 10-K under “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 unlikely 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 tax sharing agreement and reported on our balance sheet consisted of the following:   At September 30, 2017 At December 31, 2016  EFH Corp. Texas Transmission Total EFH Corp. Texas Transmission Total   Federal income taxes receivable $ (30) $ (7) $ (37) $ (62) $ (18) $ (80)  Texas margin taxes payable 16 - 16 20 - 20  Net payable (receivable) $ (14) $ (7) $ (21) $ (42) $ (18) $ (60)  Cash payments made to (received from) members related to income taxes consisted of the following:   Nine Months Ended September 30, 2017 Nine Months Ended September 30, 2016  EFH Corp. Texas Transmission Total EFH Corp. Texas Transmission Total   Federal income taxes $ (102) $ (12) $ (114) $ - $ - $ -  Texas margin taxes 20 - 20 20 - 20  Total payments (receipts) $ (82) $ (12) $ (94) $ 20 $ - $ 20  · 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 September 30, 2017, approximately 16% of the equity in an existing vendor of the company was held by a member of the Sponsor Group. During 2017 and 2016, this vendor performed transmission and distribution system construction and maintenance services for us. Cash payments were made for such services to this vendor totaling $166 million dollars for the nine months ended September 30, 2017, of which approximately $157 million was capitalized and $9 million was recor ded as an operation and maintenance expense. At September 30, 2017, we had outstanding trade payables to this vendor of $5 million.  See Note 8 for information regarding distributions to members and Note 9 for information regarding our participation in the EFH Corp. pension plan and transactions with EFH Corp. involving employee benefit matters.

Supplementary Financial Informa

Supplementary Financial Information	9 Months Ended
	Sep. 30, 2017
Supplementary Financial Information [Abstract]
SUPPLEMENTARY FINANCIAL INFORMATION	11. SUPPLEMENTARY FINANCIAL INFORMATION  Major Customers  Revenues from subsidiaries of Vistra ( subsidiaries of TCEH until October 3, 2016) represented 25% of our total operating revenues for each of the three-month periods ended September 30, 2017 and 2016, respectively, and 23% and 24% of our total operating revenues for the nine months ended September 30, 2017 and 2016, respectively. Revenues from REP subsidiaries of another nonaffiliated entity, collectively represented 20% and 19% of total operating revenues for the three months ended September 30, 2017 and 2016, respectively, and 18% and 17% of our total operating revenues for the nine months ended September 30, 2017 and 2016, respectively. No other customer represented 10% or more of our total operating revenues.  Other Income and ( Deductions )   Three Months Ended September 30, Nine Months Ended September 30,  2017 2016 2017 2016   Accretion of fair value adjustment (discount) to regulatory assets due to acquisition accounting $ - $ - $ - $ 1  Professional fees (4) (3) (12) (11)  Non-recoverable pension and OPEB (Note 9) (1) - (4) (1)  Interest income and other - - 4 -  Total other income and (deductions) - net $ (5) $ (3) $ (12) $ (11)  Interest Expense and Related Charges   Three Months Ended September 30, Nine Months Ended September 30,  2017 2016 2017 2016   Interest $ 89 $ 86 $ 263 $ 256  Amortization of debt issuance costs and discounts 1 1 2 2  Less allowance for funds used during construction – capitalized interest portion (3) (2) (8) (6)  Total interest expense and related charges $ 87 $ 85 $ 257 $ 252  Trade Accounts and Other Receivables Trade accounts and other receivables reported on our balance sheet consisted of the following:   At September 30, At December 31,  2017 2016   Gross trade accounts and other receivables $ 638 $ 548  Allowance for uncollectible accounts (4) (3)  Trade accounts receivable – net $ 634 $ 545  At September 30, 2017 and December 31, 2016, REP subsidiaries of a nonaffiliated entity collectively represented approximately 16% and 15% of the trade accounts receivable amount, respectively. At both September 30, 2017 and December 31, 2016 , REP subsidiaries of a nother nonaffiliated entity collectively represented approximately 12% of the 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 consisted of the following:   At September 30, At December 31,  2017 2016   Assets related to employee benefit plans, including employee savings programs $ 107 $ 98  Land and other investments 2 2  Total investments and other property $ 109 $ 100  Property, Plant and Equipment  Property, plant and equipment reported on our balance sheet consisted of the following:   At September 30, At December 31,  2017 2016   Total assets in service $ 20,920 $ 20,234  Less accumulated depreciation 7,130 6,836  Net of accumulated depreciation 13,790 13,398  Construction work in progress 782 416  Held for future use 15 15  Property, plant and equipment – net $ 14,587 $ 13,829  Intangible Assets  Intangible assets (other than goodwill) reported on our balance sheet as part of property, plant and equipment consisted of the following:   At September 30, 2017 At December 31, 2016  Gross Gross  Carrying Accumulated Carrying Accumulated  Amount Amortization Net Amount Amortization Net   Identifiable intangible assets subject to amortization:  Land easements $ 502 $ 98 $ 404 $ 491 $ 94 $ 397  Capitalized software 482 366 116 470 326 144  Total $ 984 $ 464 $ 520 $ 961 $ 420 $ 541  A ggregate amortization expense for intangible assets totaled $15 million and $14 milli on for the three months ended September 30, 2017 and 2016, respectively, and $44 million and $46 million for the nine months ended September 30, 2017 and 2016, respectively. The estimated aggregate amortization expense for each of the next five fiscal years is as follows:   Year Amortization Expense  2017 $ 56  2018 37  2019 34  2020 33  2021 33  At both September 30, 2017 and December 31, 2016 , goodwill totaling $ 4.1 billion was reported on our balance sheet. None of this goodwill is being deducted for tax purposes.  Employee Benefit Obligations and Other  Employee benefit obligations and other reported on our balance sheet consisted of the following:   At September 30, At December 31,  2017 2016   Retirement plans and other employee benefits $ 1,995 $ 2,092  Uncertain tax positions (including accrued interest) - 3  Investment tax credits 10 12  Other 68 61  Total employee benefit obligations and other $ 2,073 $ 2,168  In the first quarter of 2017, EFH Corp. settled all open tax claims with the IRS. As a result, we reduced the liability for uncertain tax positions by $3 million. This reduction is reported as a decrease in provision in lieu of income taxes.  Supplemental Cash Flow Information   Nine Months Ended September 30,  2017 2016   Cash payments (receipts) related to:  Interest $ 256 $ 266  Less capitalized interest (8) (6)  Interest payments (net of amounts capitalized) $ 248 $ 260  Amount in lieu of income taxes (a):  Federal (114) -  State 20 20  Total amount in lieu of income taxes $ (94) $ 20  Noncash construction expenditures (b) $ 103 $ 104 _____________ (a) See Note 10 for income tax related detail. (b) Represents end-of-period accruals.

Business and Significant Acco19

Business and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2017
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 (subsidiaries of TCEH until October 3, 2016) represented 23% and 24% of our total operating revenues for the nine month s ended September 30, 2017 and 2016 , 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 variable interest entity through December 29, 2016, at which time it was dissolved. 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.  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 not 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 Corp. Bankruptcy Proceedings	EFH Corp. Bankruptcy Proceedings  On the EFH Petition Date, the Debtors 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  These unaudited condensed financial statements should be read in conjunction with the audited financial statements and related notes included in the 2016 Form 10-K. In the opinion of Oncor management, all adjustments (consisting of normal recurring accruals) necessary for a fair presentation of the results of operations and financial position have been made. All intercompany items and transactions have been eliminated in consolidation. The results of operations for an interim period may not give a true indication of results for a full year due to seasonality. 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.
Revenue Recognition	Revenue Recognition  General  Oncor’s revenue 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.
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. 
Changes In Accounting Standards	Changes in Accounting Standards  In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-2 which created FASB Topic 842, Leases (Topic 842) . Topic 84 2 amends previous GAAP to require the balance sheet recognition of lease assets and liabilities for operating leases. Operating lease liabilities will not be classified as debt for GAAP purposes under Topic 842 and will not be treated as debt for regulatory purposes. At this time, all of Oncor’s existing leases meet the definition of an operating lease liability . Under the new rules, the recognition of any finance leases (currently known as capital leases) on the balance sheet would be classified as debt for GAAP purposes and are expected to be defined as debt for our regulatory capital structure purposes (see Note 8 for details) similar to the current capital lease treatment. We will be required to adopt Topic 842 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 initial adoption of Topic 842 will affect our balance sheet, as leased buildings and vehicles are recognized as operating lease liabilities. Subsequent to adoption, to the extent Oncor enters into f inance leases, its credit facility covenants and capitalization ratios could be impacted. We continue to evaluate the potential impact of Topic 842 on our financial statements.  Since May 2014, the FASB has issued ASU 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 are required to adopt Topic 606 by January 1, 2018 and expect to adopt at that time using the modified retrospective approach. 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 position or cash flows. We continue to evaluate the application of the new guidance.  In March 2017, the FASB issued ASU 2017-07 Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost , an amendment to Topic 715, Compensation – Retirement Benefits (Topic 715). Topic 715, as amended, will require the non-service cost components of net retirement benefit plan costs be presented as non-operating in the income statement. In addition, only the service cost component of net retirement benefit plan cost will be eligible for capitalization as part of inventory or property, plant and equipment. We are required to adopt the amendment effective January 1, 2018. The income statement presentation requirement must be applied on a retrospective basis while the capitalization eligibility requirement is applied on a prospective basis. For cash flow purposes on a prospective basis, non-service costs will be reflected as a reduction to operating cash flows, offset by lower cash used in investing activities (lower capital expenditures). At this time, we do not expect the new guidance to have a material effect on our rate-making process, our results of operations, financial position or net change in total cash flows but continue to evaluate for potential impacts.

Regulatory Assets and Liabili20

Regulatory Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2017
Regulatory Assets and Liabilities [Abstract]
Components Of Regulatory Assets And Liabilities	  Remaining Rate Recovery/Amortization Period at Carrying Amount At  September 30, 2017 September 30, 2017 December 31, 2016   Regulatory assets:  Employee retirement costs being amortized 2 years $ 11 $ 23  Unrecovered employee retirement costs incurred since the last rate review period (b) To be determined 352 327  Employee retirement liability (a)(b)(c) To be determined 804 849  Self-insurance reserve (primarily storm recovery costs) being amortized 2 years 40 64  Unrecovered self-insurance reserve incurred since the last rate review period (b) To be determined 424 367  Securities reacquisition costs (post-industry restructure) Lives of related debt 12 13  Deferred conventional meter and metering facilities depreciation Largely 3 years 62 78  Under-recovered AMS costs To be determined 213 205  Energy efficiency performance bonus (a) 1 year or less 14 10  Other regulatory assets Various 35 38  Total regulatory assets 1,967 1,974   Regulatory liabilities:  Estimated net removal costs Lives of related assets 933 819  Investment tax credit and protected excess deferred taxes Various 9 10  Over-recovered wholesale transmission service expense (a) 1 year or less 46 10  Other regulatory liabilities Various 21 17  Total regulatory liabilities 1,009 856  Net regulatory assets $ 958 $ 1,118 ____________ (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.

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2017
Long-Term Debt [Abstract]
Schedule Of Long-Term Debt	  September 30, December 31,  2017 2016   Secured:  5.000% Fixed Senior Notes due September 30, 2017 $ - $ 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 550 550  3.800% Fixed Senior Notes due September 30, 2047 325 -  Secured long-term debt 5,876 5,875  Unsecured:  Term loan credit agreement due no later than March 26, 2019 275 -  Total long-term debt 6,151 5,875  Unamortized discount and debt issuance costs (35) (36)  Less amount due currently (550) (324)  Long-term debt, less amounts due currently $ 5,566 $ 5,515 

Membership Interests (Tables)

Membership Interests (Tables)	9 Months Ended
	Sep. 30, 2017
Membership Interests [Abstract]
Schedule Of Distributions Paid	  Declaration Date Payment Date Amount  July 26, 2017 August 1, 2017 $ 65  April 26, 2017 April 27, 2017 $ 86  March 22, 2017 March 24, 2017 $ 86 
Schedule Of Changes To Membership Interests	  Capital Accounts Accumulated Other Comprehensive Income (Loss) Total Membership Interests   Balance at December 31, 2016 $ 7,822 $ (111) $ 7,711  Net income 343 - 343  Distributions (237) - (237)  Net effects of cash flow hedges (net of tax) - 1 1  Defined benefit pension plans (net of tax) - 2 2  Balance at September 30, 2017 $ 7,928 $ (108) $ 7,820   Balance at December 31, 2015 $ 7,621 $ (113) $ 7,508  Net income 355 - 355  Distributions (189) - (189)  Net effects of cash flow hedges (net of tax) - 1 1  Defined benefit pension plans (net of tax) - 1 1  Balance at September 30, 2016 $ 7,787 $ (111) $ 7,676 
Schedule Of Changes To Accumulated Other Comprehensive Income (Loss)	  Cash Flow Hedges – Interest Rate Swap Defined Benefit Pension and OPEB Plans Accumulated Other Comprehensive Income (Loss)   Balance at December 31, 2016 $ (20) $ (91) $ (111)  Defined benefit pension plans (net of tax) - 2 2  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 1 - 1  Balance at September 30, 2017 $ (19) $ (89) $ (108)   Balance at December 31, 2015 $ (22) $ (91) $ (113)  Defined benefit pension plans (net of tax) - 1 1  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 1 - 1  Balance at September 30, 2016 $ (21) $ (90) $ (111) 

Pension and OPEB Plans (Tables)

Pension and OPEB Plans (Tables)	9 Months Ended
	Sep. 30, 2017
Pension And OPEB Plans [Abstract]
Schedule Of Pension And OPEB Plan Costs	  Three Months Ended September 30, Nine Months Ended September 30,  2017 2016 2017 2016   Components of net allocated pension costs:  Service cost $ 6 $ 6 $ 18 $ 18  Interest cost 32 33 98 101  Expected return on assets (28) (30) (86) (92)  Amortization of net loss 11 10 33 30  Net pension costs 21 19 63 57  Components of net OPEB costs:  Service cost 1 2 5 6  Interest cost 12 12 36 36  Expected return on assets (2) (2) (6) (6)  Amortization of prior service cost (5) (5) (15) (15)  Amortization of net loss 8 9 24 26  Net OPEB costs 14 16 44 47  Total net pension and OPEB costs 35 35 107 104  Less amounts deferred principally as property or a regulatory asset (25) (25) (76) (75)  Net amounts recognized as expense $ 10 $ 10 $ 31 $ 29 

Related-Party Transactions (Tab

Related-Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2017
Related-Party Transactions [Abstract]
Schedule Of Related Party Transactions	Amounts payable to (receivable from) members related to income taxes under the tax sharing agreement and reported on our balance sheet consisted of the following:   At September 30, 2017 At December 31, 2016  EFH Corp. Texas Transmission Total EFH Corp. Texas Transmission Total   Federal income taxes receivable $ (30) $ (7) $ (37) $ (62) $ (18) $ (80)  Texas margin taxes payable 16 - 16 20 - 20  Net payable (receivable) $ (14) $ (7) $ (21) $ (42) $ (18) $ (60)  Cash payments made to (received from) members related to income taxes consisted of the following:   Nine Months Ended September 30, 2017 Nine Months Ended September 30, 2016  EFH Corp. Texas Transmission Total EFH Corp. Texas Transmission Total   Federal income taxes $ (102) $ (12) $ (114) $ - $ - $ -  Texas margin taxes 20 - 20 20 - 20  Total payments (receipts) $ (82) $ (12) $ (94) $ 20 $ - $ 20 

Supplementary Financial Infor25

Supplementary Financial Information (Tables)	9 Months Ended
	Sep. 30, 2017
Supplementary Financial Information [Abstract]
Schedule Of Other Income And (Deductions)	  Three Months Ended September 30, Nine Months Ended September 30,  2017 2016 2017 2016   Accretion of fair value adjustment (discount) to regulatory assets due to acquisition accounting $ - $ - $ - $ 1  Professional fees (4) (3) (12) (11)  Non-recoverable pension and OPEB (Note 9) (1) - (4) (1)  Interest income and other - - 4 -  Total other income and (deductions) - net $ (5) $ (3) $ (12) $ (11) 
Schedule Of Interest Expense And Related Charges	  Three Months Ended September 30, Nine Months Ended September 30,  2017 2016 2017 2016   Interest $ 89 $ 86 $ 263 $ 256  Amortization of debt issuance costs and discounts 1 1 2 2  Less allowance for funds used during construction – capitalized interest portion (3) (2) (8) (6)  Total interest expense and related charges $ 87 $ 85 $ 257 $ 252 
Schedule Of Trade Accounts And Other Receivables	  At September 30, At December 31,  2017 2016   Gross trade accounts and other receivables $ 638 $ 548  Allowance for uncollectible accounts (4) (3)  Trade accounts receivable – net $ 634 $ 545 
Summary of Investments And Other Property	  At September 30, At December 31,  2017 2016   Assets related to employee benefit plans, including employee savings programs $ 107 $ 98  Land and other investments 2 2  Total investments and other property $ 109 $ 100 
Schedule Of Property, Plant And Equipment	  At September 30, At December 31,  2017 2016   Total assets in service $ 20,920 $ 20,234  Less accumulated depreciation 7,130 6,836  Net of accumulated depreciation 13,790 13,398  Construction work in progress 782 416  Held for future use 15 15  Property, plant and equipment – net $ 14,587 $ 13,829 
Schedule Of Intangible Assets	  At September 30, 2017 At December 31, 2016  Gross Gross  Carrying Accumulated Carrying Accumulated  Amount Amortization Net Amount Amortization Net   Identifiable intangible assets subject to amortization:  Land easements $ 502 $ 98 $ 404 $ 491 $ 94 $ 397  Capitalized software 482 366 116 470 326 144  Total $ 984 $ 464 $ 520 $ 961 $ 420 $ 541 
Schedule Of Estimated Aggregate Amortization Expenses	  Year Amortization Expense  2017 $ 56  2018 37  2019 34  2020 33  2021 33 
Schedule Of Employee Benefit Obligations And Other	  At September 30, At December 31,  2017 2016   Retirement plans and other employee benefits $ 1,995 $ 2,092  Uncertain tax positions (including accrued interest) - 3  Investment tax credits 10 12  Other 68 61  Total employee benefit obligations and other $ 2,073 $ 2,168 
Schedule Of Supplemental Cash Flow Information	  Nine Months Ended September 30,  2017 2016   Cash payments (receipts) related to:  Interest $ 256 $ 266  Less capitalized interest (8) (6)  Interest payments (net of amounts capitalized) $ 248 $ 260  Amount in lieu of income taxes (a):  Federal (114) -  State 20 20  Total amount in lieu of income taxes $ (94) $ 20  Noncash construction expenditures (b) $ 103 $ 104 _____________ (a) See Note 10 for income tax related detail. (b) Represents end-of-period accruals.

Business And Significant Acco26

Business And Significant Accounting Policies (Narrative) (Details)	1 Months Ended	3 Months Ended		9 Months Ended
	Nov. 30, 2008	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017segmententity	Sep. 30, 2016
Business And Significant Accounting Polices [Line Items]
Number of reportable business segments | segment				0
Number of entities that would possibly be bankrupt | entity				1
Percentage of equity interest sold in the event of bankruptcy	19.75%
Oncor Holdings [Member]
Business And Significant Accounting Polices [Line Items]
Ownership		80.03%		80.03%
Texas Transmission [Member]
Business And Significant Accounting Polices [Line Items]
Percentage of membership interest owned by non-controlling owners		19.75%		19.75%
Sales [Member] | Vistra [Member]
Business And Significant Accounting Polices [Line Items]
Concentration risk percentage		25.00%	25.00%	23.00%	24.00%

EFH Bankruptcy Proceedings (Nar

EFH Bankruptcy Proceedings (Narrative) (Details) - USD ($) $ in Millions	Jul. 28, 2017	Oct. 31, 2016	Sep. 30, 2017	Aug. 15, 2017	Jul. 07, 2017
Berkshire Hathaway Energy Company (BHE) [Member]
Bankruptcy [Line Items]
Membership interests owned					80.03%
EFH Corp [Member] | Sempra Energy [Member]
Bankruptcy [Line Items]
Membership interests owned				80.03%
Texas Holdings Group [Member]
Bankruptcy [Line Items]
Amount receivable from related party			$ 129
Texas Holdings Group [Member] | NEE Merger Agreement [Member]
Bankruptcy [Line Items]
Percent of outstanding equity interests required	19.75%
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 (Narrative)

Regulatory Matters (Narrative) (Details) - USD ($) $ in Millions	Nov. 27, 2017	Sep. 30, 2017	Jul. 21, 2017
Public Utilities, General Disclosures [Line Items]
Authorized regulatory capital structure, debt		60.00%
Authorized regulatory capital structure, equity		40.00%
Merger agreement, termination right period		240 days
Scenario, Forecast [Member]
Public Utilities, General Disclosures [Line Items]
Requested base rate revenue before intercompany eliminations	$ 4,300
Authorized return on equity	9.80%
Authorized regulatory capital structure, debt	57.50%
Authorized regulatory capital structure, equity	42.50%
Oncor Merger Assets [Member]
Public Utilities, General Disclosures [Line Items]
Net book value of assets			$ 380
SDTS Merger Assets [Member]
Public Utilities, General Disclosures [Line Items]
Net book value of assets			401
Sharyland Distribution & Transmission Services (SDTS) [Member]
Public Utilities, General Disclosures [Line Items]
Amount owed			20
Sharyland Utilities (SU) [Member]
Public Utilities, General Disclosures [Line Items]
Amount owed			$ 6.5

Regulatory Assets And Liabili29

Regulatory Assets And Liabilities (Components Of Regulatory Assets And Liabilities) (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2017	Dec. 31, 2016
Regulatory Assets And Liabilities [Line Items]
Carrying Amount, Regulatory Assets		$ 1,967	$ 1,974
Carrying Amount, Regulatory Liabilities		1,009	856
Net regulatory asset		$ 958	1,118
Estimated Net Removal Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		Lives of related assets
Carrying Amount, Regulatory Liabilities		$ 933	819
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		$ 9	10
Over-Recovered Wholesale Transmission Service Expense [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[1]	1 year or less
Carrying Amount, Regulatory Liabilities	[1]	$ 46	10
Other Regulatory Liabilities [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		Various
Carrying Amount, Regulatory Liabilities		$ 21	17
Employee Retirement Costs Being Amortized [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		2 years
Carrying Amount, Regulatory Assets		$ 11	23
Unrecovered Employee Retirement Costs Incurred Since The Last Rate Review Period [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[2]	To be determined
Carrying Amount, Regulatory Assets	[2]	$ 352	327
Employee Retirement Liability [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[1],[2],[3]	To be determined
Carrying Amount, Regulatory Assets	[1],[2],[3]	$ 804	849
Self-Insurance Reserve (Primarily Storm Recovery Costs) Being Amortized [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		2 years
Carrying Amount, Regulatory Assets		$ 40	64
Unrecovered Self-Insurance Reserve Incurred Since The Last Rate Review Period [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[2]	To be determined
Carrying Amount, Regulatory Assets	[2]	$ 424	367
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		$ 12	13
Deferred Conventional Meter And Metering Facilities Depreciation [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		Largely 3 years
Carrying Amount, Regulatory Assets		$ 62	78
Under-recovered AMS Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		To be determined
Carrying Amount, Regulatory Assets		$ 213	205
Energy Efficiency Performance Bonus [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	[1]	1 year or less
Carrying Amount, Regulatory Assets	[1]	$ 14	10
Other Regulatory Assets [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period		Various
Carrying Amount, Regulatory Assets		$ 35	$ 38
[1]	Not earning a return in the regulatory rate-setting process.
[2]	Recovery is specifically authorized by statute or by the PUCT, subject to reasonableness review.
[3]	Represents unfunded liabilities recorded in accordance with pension and OPEB accounting standards.

Short-Term Borrowings (Narrativ

Short-Term Borrowings (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)item	Dec. 31, 2016USD ($)
Line of Credit Facility [Line Items]
Outstanding borrowing under the revolving credit facility	$ 917	$ 789
Outstanding borrowing, interest rate	2.22%	1.72%
Letters of credit	$ 9	$ 7
Commitment fee	0.10%
Borrowing capacity available under the credit facility	$ 1,074	$ 1,204
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	0.65
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 revolving credit facilities extension options | item	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
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 ($) $ in Millions	1 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Long-Term Debt [Line Items]
Repayments of long-term debt		$ 324	$ 41
Aggregate principal amount	$ 5,876	5,876		$ 5,875
Term loan	275	$ 275
Percentage of fair value of cost of property additions certified to the Deed of Trust collateral agent		85.00%
Available bond credits	2,495	$ 2,495
Future debt subject to property additions to the Deed of Trust	2,109	2,109
Estimated fair value of our long-term debt including current maturities	7,093	7,093		6,751
Carrying amount	$ 6,116	$ 6,116		$ 5,839
London Interbank Offered Rate (LIBOR) [Member]
Long-Term Debt [Line Items]
Spread over variable rate		1.00%
Federal Funds Effective Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate		0.50%
One-Month London Interbank Offered Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate		1.00%
5.000% Fixed Senior Notes Due September 30, 2017 [Member]
Long-Term Debt [Line Items]
Repayments of long-term debt		$ 324
Due date		Sep. 30, 2017		Sep. 30, 2017
Aggregate principal amount				$ 324
Interest percentage	5.00%	5.00%		5.00%
3.800% Fixed Senior Notes Due September 30, 2047 [Member]
Long-Term Debt [Line Items]
Due date		Sep. 30, 2047		Sep. 30, 2047
Aggregate principal amount	$ 325	$ 325
Interest percentage	3.80%	3.80%		3.80%
Proceeds from sale of Notes	$ 321
Percentage of principal amount plus accrued and unpaid interest and make-whole premium		100.00%
Number of days after issuance date for exchange offer completion		315 days
Number of days after shelf registration filing obligation for filing to be effective		270 days
Increase in basis points per annum		0.50%
Term Loan Credit Agreement Due No Later Than March 26, 2019 [Member]
Long-Term Debt [Line Items]
Due date		Mar. 26, 2019		Mar. 26, 2019
Interest percentage	2.138%	2.138%
Loan term		18 months
Senior debt to capitalization ratio		0.65
Excess of principal amount for default	$ 100	$ 100
Judgment for payment of money on term loan	50	$ 50
Time alloted for excess debt default to be discharged		60 days
Term Loan Credit Agreement Due No Later Than March 26, 2019 [Member] | Federal Funds Effective Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate		0.50%
Term Loan Credit Agreement Due No Later Than March 26, 2019 [Member] | One-Month London Interbank Offered Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate		1.00%
3.750% Fixed Senior Notes Due April 1, 2045 [Member]
Long-Term Debt [Line Items]
Due date		Apr. 1, 2045		Apr. 1, 2045
Aggregate principal amount	$ 550	$ 550		$ 550
Interest percentage	3.75%	3.75%		3.75%
6.800% Fixed Senior Notes Due September 1, 2018 [Member]
Long-Term Debt [Line Items]
Due date		Sep. 1, 2018		Sep. 1, 2018
Aggregate principal amount	$ 550	$ 550		$ 550
Interest percentage	6.80%	6.80%		6.80%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Long-Term Debt [Line Items]
Spread over variable rate		1.00%
Minimum [Member] | One-Month London Interbank Offered Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate		0.00%
Minimum [Member] | Term Loan Credit Agreement Due No Later Than March 26, 2019 [Member] | London Interbank Offered Rate (LIBOR) [Member]
Long-Term Debt [Line Items]
Spread over variable rate		0.80%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Long-Term Debt [Line Items]
Spread over variable rate		1.75%
Maximum [Member] | One-Month London Interbank Offered Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate		0.75%
Maximum [Member] | Term Loan Credit Agreement Due No Later Than March 26, 2019 [Member] | London Interbank Offered Rate (LIBOR) [Member]
Long-Term Debt [Line Items]
Spread over variable rate		0.90%

Long-Term Debt (Schedule Of Lon

Long-Term Debt (Schedule Of Long-Term Debt) (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Secured long-term debt	$ 5,876	$ 5,875
Term loan	275
Total long-term debt	6,151	5,875
Unamortized discount and debt issuance costs	(35)	(36)
Less amount due currently	(550)	(324)
Long-term debt, less amounts due currently	$ 5,566	5,515
5.000% Fixed Senior Notes Due September 30, 2017 [Member]
Debt Instrument [Line Items]
Secured long-term debt		$ 324
Interest percentage	5.00%	5.00%
Due date	Sep. 30, 2017	Sep. 30, 2017
6.800% Fixed Senior Notes Due September 1, 2018 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 550	$ 550
Interest percentage	6.80%	6.80%
Due date	Sep. 1, 2018	Sep. 1, 2018
2.150% Fixed Senior Notes Due June 1, 2019 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 250	$ 250
Interest percentage	2.15%	2.15%
Due date	Jun. 1, 2019	Jun. 1, 2019
5.750% Fixed Senior Notes Due September 30, 2020 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 126	$ 126
Interest percentage	5.75%	5.75%
Due date	Sep. 30, 2020	Sep. 30, 2020
4.100% Fixed Senior Notes Due June 1, 2022 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 400	$ 400
Interest percentage	4.10%	4.10%
Due date	Jun. 1, 2022	Jun. 1, 2022
7.000% Fixed Debentures Due September 1, 2022 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 800	$ 800
Interest percentage	7.00%	7.00%
Due date	Sep. 1, 2022	Sep. 1, 2022
2.950% Fixed Senior Notes Due April 1, 2025 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 350	$ 350
Interest percentage	2.95%	2.95%
Due date	Apr. 1, 2025	Apr. 1, 2025
7.000% Fixed Senior Notes Due May 1, 2032 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 500	$ 500
Interest percentage	7.00%	7.00%
Due date	May 1, 2032	May 1, 2032
7.250% Fixed Senior Notes Due January 15, 2033 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 350	$ 350
Interest percentage	7.25%	7.25%
Due date	Jan. 15, 2033	Jan. 15, 2033
7.500% Fixed Senior Notes Due September 1, 2038 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 300	$ 300
Interest percentage	7.50%	7.50%
Due date	Sep. 1, 2038	Sep. 1, 2038
5.250% Fixed Senior Notes Due September 30, 2040 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 475	$ 475
Interest percentage	5.25%	5.25%
Due date	Sep. 30, 2040	Sep. 30, 2040
4.550% Fixed Senior Notes Due December 1, 2041 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 400	$ 400
Interest percentage	4.55%	4.55%
Due date	Dec. 1, 2041	Dec. 1, 2041
5.300% Fixed Senior Notes Due June 1, 2042 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 500	$ 500
Interest percentage	5.30%	5.30%
Due date	Jun. 1, 2042	Jun. 1, 2042
3.750% Fixed Senior Notes Due April 1, 2045 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 550	$ 550
Interest percentage	3.75%	3.75%
Due date	Apr. 1, 2045	Apr. 1, 2045
3.800% Fixed Senior Notes Due September 30, 2047 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 325
Interest percentage	3.80%	3.80%
Due date	Sep. 30, 2047	Sep. 30, 2047
Term Loan Credit Agreement Due No Later Than March 26, 2019 [Member]
Debt Instrument [Line Items]
Interest percentage	2.138%
Due date	Mar. 26, 2019	Mar. 26, 2019
Bondco [Member]
Debt Instrument [Line Items]
Less amount due currently	$ (550)	$ (324)

Membership Interests (Narrative

Membership Interests (Narrative) (Details) - USD ($) $ in Millions	Nov. 27, 2017	Oct. 25, 2017	Sep. 30, 2017	Sep. 30, 2016
Subsequent Event [Line Items]
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			$ 25
Regulatory capitalization ratio, debt			59.90%
Regulatory capitalization ratio, equity			40.10%
Cash distribution to members			$ 237	$ 189
Scenario, Forecast [Member]
Subsequent Event [Line Items]
Assumed debt to equity ratio, debt	57.50%
Assumed debt to equity ratio, equity	42.50%
Subsequent Event [Member]
Subsequent Event [Line Items]
Cash distribution to members		$ 32
Contingent equity distribution		$ 250

Membership Interests (Schedule

Membership Interests (Schedule Of Distributions Paid) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Dividends Payable [Line Items]
Amount	$ 237	$ 189
Payment One FY 2017 [Member]
Dividends Payable [Line Items]
Declaration Date	Jul. 26, 2017
Payment Date	Aug. 1, 2017
Amount	$ 65
Payment Two FY 2017 [Member]
Dividends Payable [Line Items]
Declaration Date	Apr. 26, 2017
Payment Date	Apr. 27, 2017
Amount	$ 86
Payment Three FY 2017 [Member]
Dividends Payable [Line Items]
Declaration Date	Mar. 22, 2017
Payment Date	Mar. 24, 2017
Amount	$ 86

Membership Interests (Schedul35

Membership Interests (Schedule Of Changes To Membership Interests) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Balance			$ 7,711	$ 7,508
Net income	$ 157	$ 163	343	355
Distributions			(237)	(189)
Net effects of cash flow hedges (net of tax)		1	1	1
Defined benefit pension plans (net of tax)	1		2	1
Balance	7,820	7,676	7,820	7,676
Capital Accounts [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Balance			7,822	7,621
Net income			343	355
Distributions			(237)	(189)
Net effects of cash flow hedges (net of tax)
Defined benefit pension plans (net of tax)
Balance	7,928	7,787	7,928	7,787
Accumulated Other Comprehensive Income (Loss) [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Balance			(111)	(113)
Net income
Distributions
Net effects of cash flow hedges (net of tax)			1	1
Defined benefit pension plans (net of tax)			2	1
Balance	$ (108)	$ (111)	$ (108)	$ (111)

Membership Interests (Schedul36

Membership Interests (Schedule Of Changes To Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (111)
Balance at end of period	(108)
Cash Flow Hedges - Interest Rate Swap [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(20)	$ (22)
Defined benefit pension plans (net of tax)
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges	1	1
Balance at end of period	(19)	(21)
Defined Benefit Pension and OPEB Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(91)	(91)
Defined benefit pension plans (net of tax)	2	1
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges
Balance at end of period	(89)	(90)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(111)	(113)
Defined benefit pension plans (net of tax)	2	1
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges	1	1
Balance at end of period	$ (108)	$ (111)

Pension And OPEB Plans (Narrati

Pension And OPEB Plans (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017USD ($)
Oncor Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.04%
Expected return on plan assets	5.17%
Vistra Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.28%
Expected return on plan assets	5.13%
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash contributions	$ 128
Additional cash contributions	21
Additional cash contributions, next five years	$ 564
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.35%
Expected return on plan assets	6.10%
Cash contributions	$ 25
Additional cash contributions	6
Additional cash contributions, next five years	$ 153

Pension And OPEB Plans (Schedul

Pension And OPEB Plans (Schedule Of Pension And OPEB Plan Costs) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Net costs	$ 35	$ 35	$ 107	$ 104
Less amounts deferred principally as property or a regulatory asset	(25)	(25)	(76)	(75)
Net amounts recognized as expense	10	10	31	29
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	6	18	18
Interest cost	32	33	98	101
Expected return on assets	(28)	(30)	(86)	(92)
Amortization of net loss	11	10	33	30
Net costs	21	19	63	57
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1	2	5	6
Interest cost	12	12	36	36
Expected return on assets	(2)	(2)	(6)	(6)
Amortization of prior service cost	(5)	(5)	(15)	(15)
Amortization of net loss	8	9	24	26
Net costs	$ 14	$ 16	$ 44	$ 47

Related-Party Transactions (Nar

Related-Party Transactions (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Related Party Transaction [Line Items]
Revenues from electricity delivery fees	$ 265		$ 700
TCEH [Member]
Related Party Transaction [Line Items]
Revenues from electricity delivery fees	265		700
EFH Corp [Member]
Related Party Transaction [Line Items]
Shared facilities expense	1		3
Sponsor Group [Member]
Related Party Transaction [Line Items]
Equity in existing vendor		16.00%
Cash payments to vendors related to Texas margin taxes		$ 166
Trade payables related parties		5
Sponsor Group [Member] | Capitalized [Member]
Related Party Transaction [Line Items]
Cash payments to vendors related to Texas margin taxes		157
Sponsor Group [Member] | Operation And Maintenance Expense [Member]
Related Party Transaction [Line Items]
Cash payments to vendors related to Texas margin taxes		$ 9
Maximum [Member] | EFH Corp [Member]
Related Party Transaction [Line Items]
Administrative and services costs	1		1
Shared facilities payments received	$ 1		$ 1

Related-Party Transactions (Sch

Related-Party Transactions (Schedule Of Related Party Transactions) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Federal income taxes receivable	$ (37)	$ (80)
Texas margin taxes payable	16	20
Net payable (receivable)	(21)	(60)
EFH Corp [Member]
Related Party Transaction [Line Items]
Federal income taxes receivable	(30)	(62)
Texas margin taxes payable	16	20
Net payable (receivable)	(14)	(42)
Texas Transmission Investment LLC [Member]
Related Party Transaction [Line Items]
Federal income taxes receivable	(7)	(18)
Net payable (receivable)	$ (7)	$ (18)

Related-Party Transactions (Cas

Related-Party Transactions (Cash Payments Made To (Received From) Members Related To Income Taxes) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Related Party Transaction [Line Items]
Federal income taxes	$ (114)
Texas margin taxes	20	$ 20
Total payments (receipts)	(94)	20
EFH Corp [Member]
Related Party Transaction [Line Items]
Federal income taxes	(102)
Texas margin taxes	20	20
Total payments (receipts)	(82)	$ 20
Texas Transmission Investment LLC [Member]
Related Party Transaction [Line Items]
Federal income taxes	(12)
Total payments (receipts)	$ (12)

Supplementary Financial Infor42

Supplementary Financial Information (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Supplemental Financial Information [Line Items]
Aggregate amortization expenses	$ 15		$ 14	$ 44	$ 46
Goodwill	$ 4,064			$ 4,064		$ 4,064
Increase (decrease) in liability for uncertain tax positions		$ (3)
Sales [Member] | Vistra [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage	25.00%		25.00%	23.00%	24.00%
Sales [Member] | Nonaffiliated REP [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage	20.00%		19.00%	18.00%	17.00%
Trade Accounts Receivable [Member] | Nonaffiliated REP [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage				16.00%		15.00%
Trade Accounts Receivable [Member] | Second Nonaffiliated REP [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage				12.00%		12.00%

Supplementary Financial Infor43

Supplementary Financial Information (Schedule Of Other Income And (Deductions)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Supplementary Financial Information [Abstract]
Accretion of fair value adjustment (discount) to regulatory assets due to acquisition accounting				$ 1
Professional fees	$ (4)	$ (3)	$ (12)	(11)
Non-recoverable pension and OPEB (Note 9)	(1)		(4)	(1)
Interest income and other			4
Total other income and (deductions) - net	$ (5)	$ (3)	$ (12)	$ (11)

Supplementary Financial Infor44

Supplementary Financial Information (Schedule Of Interest Expense And Related Charges) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Supplementary Financial Information [Abstract]
Interest	$ 89	$ 86	$ 263	$ 256
Amortization of debt issuance costs and discounts	1	1	2	2
Less allowance for funds used during construction — capitalized interest portion	(3)	(2)	(8)	(6)
Total interest expense and related charges	$ 87	$ 85	$ 257	$ 252

Supplementary Financial Infor45

Supplementary Financial Information (Schedule Of Trade Accounts And Other Receivables) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Supplementary Financial Information [Abstract]
Gross trade accounts and other receivables	$ 638	$ 548
Allowance for uncollectible accounts	(4)	(3)
Trade accounts receivable - net	$ 634	$ 545

Supplementary Financial Infor46

Supplementary Financial Information (Summary of Investments And Other Property) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Supplementary Financial Information [Abstract]
Assets related to employee benefit plans, including employee savings programs	$ 107	$ 98
Land and other investments	2	2
Total investments and other property	$ 109	$ 100

Supplementary Financial Infor47

Supplementary Financial Information (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Supplementary Financial Information [Abstract]
Total assets in service	$ 20,920	$ 20,234
Less accumulated depreciation	7,130	6,836
Net of accumulated depreciation	13,790	13,398
Construction work in progress	782	416
Held for future use	15	15
Property, plant and equipment - net	$ 14,587	$ 13,829

Supplementary Financial Infor48

Supplementary Financial Information (Schedule Of Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 984	$ 961
Accumulated Amortization	464	420
Net	520	541
Land Easements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	502	491
Accumulated Amortization	98	94
Net	404	397
Capitalized Software [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	482	470
Accumulated Amortization	366	326
Net	$ 116	$ 144

Supplementary Financial Infor49

Supplementary Financial Information (Schedule Of Estimated Aggregate Amortization Expenses) (Details) $ in Millions	Sep. 30, 2017USD ($)
Supplementary Financial Information [Abstract]
2,017	$ 56
2,018	37
2,019	34
2,020	33
2,021	$ 33

Supplementary Financial Infor50

Supplementary Financial Information (Schedule Of Employee Benefit Obligations And Other) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Supplementary Financial Information [Abstract]
Retirement plans and other employee benefits	$ 1,995	$ 2,092
Uncertain tax positions (including accrued interest)		3
Investment tax credits	10	12
Other	68	61
Total employee benefit obligations and other	$ 2,073	$ 2,168

Supplementary Financial Infor51

Supplementary Financial Information (Schedule Of Supplemental Cash Flow Information) (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016
Supplementary Financial Information [Abstract]
Interest		$ 256	$ 266
Less capitalized interest		(8)	(6)
Interest payments (net of amounts capitalized)		248	260
Federal	[1]	(114)
State	[1]	20	20
Total amount in lieu of income taxes	[1]	(94)	20
Noncash construction expenditures	[2]	$ 103	$ 104
[1]	See Note 10 for income tax related detail.
[2]	Represents end-of-period accruals.