Oncor Electric Delivery 10-Q 1 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 01, 2019
Entity Registrant Name	ONCOR ELECTRIC DELIVERY CO LLC
Entity Central Index Key	0001193311
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Trading Symbol	None
Title of 12(b) Security	None
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		0
Entity Current Reporting Status	No
Oncor Electric Delivery Holdings Company LLC [Member]
Entity Outstanding Membership Interests		80.25%
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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Condensed Statements Of Consolidated Income [Abstract]
Operating revenues (Note 3)	$ 1,211	$ 1,095	$ 3,268	$ 3,106
Operating expenses:
Wholesale transmission service	245	237	759	719
Operation and maintenance	222	214	647	636
Depreciation and amortization	186	169	536	503
Provision in lieu of income taxes (Note 9)	55	54	111	134
Taxes other than amounts related to income taxes	134	128	377	374
Total operating expenses	842	802	2,430	2,366
Operating income	369	293	838	740
Other deductions and (income) - net (Note 10)	14	13	56	63
Nonoperating provision (benefit) in lieu of income taxes (Note 5)	(5)	(3)	(12)	(13)
Interest expense and related charges (Note 10)	97	89	276	264
Net income	$ 263	$ 194	$ 518	$ 426

Condensed Statements Of Conso_2

Condensed Statements Of Consolidated Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Condensed Statements Of Consolidated Comprehensive Income [Abstract]
Net income	$ 263	$ 194	$ 518	$ 426
Other comprehensive income (loss):
Net effects of cash flow hedges (net of tax) (Note 1)			(2)	2
Defined benefit pension plans (net of tax)	1	1	4	2
Total other comprehensive income (loss)	1	1	2	4
Comprehensive income	$ 264	$ 195	$ 520	$ 430

Condensed Statements Of Conso_3

Condensed Statements Of Consolidated Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows - operating activities:
Net income	$ 518	$ 426
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization, including regulatory amortization	599	589
Provision in lieu of deferred income taxes	40	37
Other - net	(2)	(1)
Changes in operating assets and liabilities:
Regulatory accounts related to reconcilable tariffs (Note 2)	(58)	130
Other operating assets and liabilities	(323)	(100)
Cash provided by operating activities	774	1,081
Cash flows - financing activities:
Issuances of long-term debt (Note 5)	2,460	800
Repayments of long-term debt (Note 5)	(742)	(825)
Proceeds of business acquisition bridge loan (Note 4)	600
Repayment of business acquisition bridge loan (Note 4)	(600)
Payment of acquired entity credit facilities	(114)
Net change in short-term borrowings (Note 4)	(813)	149
Capital contributions from members (Note 7)	1,540	144
Issuance of short-term notes under the CP Program (Note 6)	600
Distributions to members (Note 7)	(213)	(30)
Debt discount, premium, financing and reacquisition costs - net	(41)	(9)
Cash provided by financing activities	2,077	229
Cash flows - investing activities:
Capital expenditures	(1,539)	(1,345)
Business acquisition (Note 11)	(1,324)
Other - net	19	15
Cash used in investing activities	(2,844)	(1,330)
Net change in cash and cash equivalents	7	(20)
Cash and cash equivalents - beginning balance	3	21
Cash and cash equivalents - ending balance	$ 10	$ 1

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 10	$ 3
Trade accounts receivable - net (Note 10)	784	559
Materials and supplies inventories - at average cost	150	116
Prepayments and other current assets	96	94
Total current assets	1,040	772
Investments and other property (Note 10)	127	120
Property, plant and equipment - net (Note 10)	18,973	16,090
Goodwill (Note 1)	4,739	4,064
Regulatory assets (Note 2)	1,765	1,691
Operating lease ROU assets and other (Note 6)	100	15
Total assets	26,744	22,752
Current liabilities:
Short-term borrowings (Note 4)		813
Long-term debt due currently (Note 5)	485	600
Trade accounts payable	353	300
Amounts payable to members related to income taxes (Note 9)	29	26
Accrued taxes other than amounts related to income	191	199
Accrued interest	95	68
Operating lease and other current liabilities (Note 6)	213	209
Total current liabilities	1,366	2,215
Long-term debt, less amounts due currently (Note 5)	8,491	5,835
Liability in lieu of deferred income taxes (Note 9)	1,791	1,602
Regulatory liabilities (Note 2)	2,780	2,697
Employee benefit, operating lease and other obligations (Notes 6, 8 and 10)	2,005	1,943
Total liabilities	16,433	14,292
Commitments and contingencies (Note 6)
Membership interests (Note 7):
Capital account ― number of interests outstanding 2019 and 2018 – 635,000,000	10,472	8,624
Accumulated other comprehensive loss	(161)	(164)
Total membership interests	10,311	8,460
Total liabilities and membership interests	$ 26,744	$ 22,752

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - shares	Sep. 30, 2019	Dec. 31, 2018
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, 2019
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 subsidiaries. See “Glossary” for definition of terms and abbreviations.  We are a regulated electricity transmission and distribution company primarily engaged in providing delivery services to REPs that sell power in the north-central, eastern, western and panhandle regions of Texas. We are a direct, majority-owned subsidiary of Oncor Holdings, which is indirectly wholly owned by Sempra. Oncor Holdings owns 80.25% of our membership interests and Texas Transmission owns 19.75% of our membership interests. We are managed as an integrated business; consequently, there are no separate reportable business segments.  Our consolidated financial statements include the results of our wholly owned indirect subsidiary , NTU, which is a regulated utility that provides electricity transmission delivery service in the north-central , western and panhandle regions of Texas. We acquired NTU as part of the InfraREIT Acquisition that closed on May 16, 2019.  Various “ring-fencing” measures have been taken to enhance our credit quality and the separateness between the Oncor Ring-Fenced Entities, Sempra and its affiliates (other than the Oncor Ring-Fenced Entities), and any other entities with a direct or indirect ownership interest in Oncor or Oncor Holdings. These measures serve to mitigate the Oncor Ring-Fenced Entities’ credit exposure to Sempra and its affiliates and any other direct or indirect owners of Oncor and Oncor Holdings, and to reduce the risk that the assets and liabilities of Oncor Ring-Fenced Entities would be substantively consolidated with the assets and liabilities of any Sempra entity or any other direct or indirect owners of Oncor and Oncor Holdings in connection with a bankruptcy of any such entities. Such measures include, among other things: the 19.75% equity interest held by Texas Transmission; maintenance of separate books and records for the Oncor Ring-Fenced Entities; and our board of directors being comprised of a majority of directors who meet certain independent/disinterested director standards. As a result, none of the assets of the Oncor Ring-Fenced Entities are available to satisfy the debt or obligations of any Sempra entity or any other direct or indirect owner of Oncor or Oncor Holdings. The assets and liabilities of the Oncor Ring-Fenced Entities are separate and distinct from those of any Sempra entities and any other direct or indirect owner of Oncor or Oncor Holdings. We do not bear any liability for debt or contractual obligations of Sempra and its affiliates or any other direct or indirect owner of Oncor or Oncor Holdings, and vice versa. Accordingly, our operations are conducted, and our cash flows are managed, independently from Sempra and its affiliates and any other direct or indirect owner of Oncor or Oncor Holdings. Basis of Presentation  These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements and related notes included in our 2018 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. We have evaluated all subsequent events through the date the financial statements were issued. All appropriate 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 (see Note 13 to Financial Statements in our 2018 Form 10-K for additional information regarding quarterly results of operations). Our consolidated financial statements have been prepared in accordance with GAAP governing rate-regulated operations. All dollar amounts in the financial statements and tables in the notes are stated in millions of U.S. dollars unless otherwise indicated.  Use of Estimates  Preparation of our financial statements requires management to make estimates and assumptions about future events that affect the reporting of assets and liabilities at the balance sheet dates and the reported amounts of revenue and expense, including fair value measurements. In the event estimates and/or assumptions prove to be different from actual amounts, adjustments are made in subsequent periods to reflect more current information. No material adjustments were made to previous estimates or assumptions during the current period.  Goodwill  We discuss goodwill in Note 1 to Financial Statements in our 2018 Form 10-K. The increase in goodwill from $4,064 million at December 31, 2018 to $4,7 39 million at September 30, 2019 is due to the InfraREIT Acquisition. See Note 11 for more information on the InfraREIT Acquisition.  Changes in Accounting Standards  Topic 842, “Leases” – In February 2016, the FASB issued ASU 2016-02 which created FASB Topic 842, Leases (Topic 842). Topic 842 amends previous GAAP to require the balance sheet recognition of substantially all lease assets and liabilities, including operating leases. Operating lease liabilities are not classified as debt for GAAP purposes under Topic 842 and are not treated as debt for our regulatory purposes. All of Oncor’s existing leases meet the definition of an operating lease. Under the new rules, the recognition of any finance leases (previously known as capital leases) on the balance sheet are classified as debt for both GAAP and regulatory capital structure purposes (see Note 7 for details) similar to the previous capital lease treatment.  We adopted Topic 842 on January 1, 2019, using the optional transition method to apply the new guidance prospectively and not restate comparative periods. We elected the package of practical expedients that permits us to not reassess (a) whether a contract is or contains a lease, (b) lease classification or (c) determination of initial direct costs, which allows us to carry forward accounting conclusions under previous GAAP on contracts that commenced prior to adoption of the lease standard. We also elected the land easement practical expedient, which allows us to continue to account for pre-existing land easements under our accounting policy that existed before adoption of the lease standard. We did not elect the practical expedient to use hindsight in making judgments when determining the lease term.  The adoption of Topic 842 affects our balance sheet, as our contracts for office space, service centers and fleet vehicles are operating leases. The following table shows the increases on our balance sheet at January 1, 2019 from the initial adoption of Topic 842.   At January 1, 2019  Operating Leases:  ROU assets:  Operating lease ROU and other assets $ 82   Lease liabilities:  Other current liabilities $ 26  Employee benefit, operating lease and other obligations 56  Total operating lease liabilities $ 82  Topic 220, “Income Statement—Reporting Comprehensive Income” amended by ASU 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” – In February 2018, the FASB issued ASU 2018-02, an amendment to Topic 220. Under ASU 2018-02, an entity is required to provide certain disclosures regarding stranded tax effects, including its accounting policy related to releasing the income tax effects from accumulated other comprehensive income (AOCI). We elected to reclassify stranded tax effects resulting from the TCJA from AOCI to capital accounts. Our stranded tax effects in AOCI, which are related to previous interest rate cash flow hedges, were $4 million and increased our capital account upon reclassification. We adopted the standard on a prospective basis effective January 1, 2019.   Topic 350, “Intangibles, Goodwill and Other —Internal-Use Software (Subtopic 40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service ” – In August 2018, the FASB issued ASU 2018-15 which clarifies the accounting for implementation costs in cloud computing arrangements. ASU 2018-15 is required to be adopted in the first quarter of fiscal 2020 with earlier adoption permitted. We have early adopted on a prospective basis effective July 1, 2019. The early adoption is not expected to have a material effect on our consolidated financial statements.

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2019
Regulatory Matters [Abstract]
REGULATORY MATTERS	2. REGULATORY MATTERS  Regulatory Assets and Liabilities  Recognition of regulatory assets and liabilities and the periods over which they are to be recovered or refunded through rate regulation reflect the decisions of the PUCT. Components of our regulatory assets and liabilities and their remaining recovery periods as of September 30, 2019 are provided in the table below. Amounts not currently earning a return through rate regulation are noted.   Remaining Rate Recovery /Amortization Period  At September 30, 2019 At September 30, 2019 At December 31, 2018  Regulatory assets:  Employee retirement liability (a)(b)(c) To be determined $ 624 $ 648  Employee retirement costs being amortized 8 years 270 297  Employee retirement costs incurred since the last rate review period (b) To be determined 77 73  Self-insurance reserve (primarily storm recovery costs) being amortized 8 years 319 351  Self-insurance reserve incurred since the last rate review period (primarily storm related) (b) To be determined 200 59  Securities reacquisition costs Lives of related debt 30 10  Deferred conventional meter and metering facilities depreciation 1 year 21 36  Under-recovered AMS costs 8 years 169 185  Energy efficiency performance bonus (a) 1 year or less 11 7  Wholesale distribution substation service To be determined 30 15  Other regulatory assets Various 14 10  Total regulatory assets 1,765 1,691   Regulatory liabilities:  Estimated net removal costs Lives of related assets 1,154 1,023  Excess deferred taxes Primarily over lives of related assets 1,592 1,571  Over-recovered wholesale transmission service expense (a) 1 year or less 13 89  Other regulatory liabilities Various 21 14  Total regulatory liabilities 2,780 2,697  Net regulatory assets (liabilities) $ (1,015) $ (1,006) ____________ (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.  InfraREIT Acquisition Approval (PUCT Docket No. 48929)  On May 9, 2019, the PUCT issued a final order in Docket No. 48929 approving the transactions contemplated by the InfraREIT Acquisition, including the SDTS-SU Asset Exchange, and the Sempra-Sharyland Transaction. For more information on these transactions, see Note 11.  Regulatory Status of the TCJA  The excess deferred tax related balances above are primarily the result of the TCJA corporate federal income tax rate reduction from 35% to 21% . These regulatory liabilities reflect our obligation, as required by PUCT order in Docket No. 46957, to refund to utility customers any excess deferred tax related balances created by the reduction in the corporate federal income tax rate through reductions in our tariffs.  Docket No. 48325  In 2018, we made filings to incorporate the impacts of the TCJA into our tariffs, including the reduction in the corporate income tax rate from 35% to 21% and amortization of excess deferred federal income taxes. In the filings, we proposed a total net decrease in the revenue requirement used to set transmission and distribution rates of approximately $181 million annually as compared to the revenue requirement approved in Oncor’s most recent rate review, PUCT Docket No. 46957. In September 2018, we reached an unopposed stipulation regarding an overall settlement of the TCJA impacts. The settlement included, on an annual basis, $144 million related to the reduction of income tax expense currently in rates and $75 million related to amortization of excess deferred federal income taxes.  The settlement rates were implemented on an interim basis during 2018 and were approved by the PUCT on April 4, 2019. These rates include the refund of the unprotected portion of excess deferred federal income taxes over a ten-year period and the protected portion over the lives of the related assets.  Docket No. 49160  During 2018, interim TCOS rates included refunds of excess deferred federal income taxes that were lower than the amount approved by the PUCT. We proposed refunding the related $9 million regulatory liability balance at March 31, 2019 over a one-month period as part of our Docket No. 49160 interim TCOS update filed in January 2019. This TCOS filing was approved by the PUCT on April 26, 2019 and a total refund of $9 million was made in April and May of 2019.  DCRF (PUCT Docket No. 49427)  On April 8, 2019, we filed with the PUCT, as well as with cities with original jurisdiction over our rates, an application for approval of an updated DCRF. The DCRF allows us to recover, primarily through our tariff for retail delivery service, certain costs related to our distribution investments. In our DCRF application, we requested a $29 million increase in annual distribution revenues related to 2018 distribution investments. On May 30, 2019, a stipulated settlement agreement among the parties to the proceeding was reached that included a $25 million increase in annual distribution revenues, and, on June 10, 2019, interim rates based on the stipulated settlement agreement were authorized to begin on September 1, 2019. On September 12, 2019, the PUCT issued a final order implementing the settlement agreement and rates.  AMS Final Reconciliation (PUCT Docket No. 49721 )  On July 9, 2019, we filed a request with the PUCT for a final reconciliation of our AMS costs. Effective with the implementation of rates pursuant to the Docket No. 46957 rate review, we ceased recovering AMS charges through a surcharge on November 26, 2017, and AMS costs are now being recovered through base rates. We made the following requests in our AMS reconciliation filing: · a reconciliation of all costs incurred with the $87 million of revenues collected during the final period of the AMS surcharge from January 1, 2017 to November 26, 2017, · a final PUCT determination of the net operating cost savings of $16 million from the final period of our AMS deployment that were used to reduce the amount of costs that were ultimately recovered through our AMS surcharge, · authorization to add the under-recovery of the 2017 AMS costs from this reconciliation proceeding of $6 million to the existing AMS regulatory asset currently being recovered through base rates, and · authorization to establish a regulatory asset to capture the costs associated with this reconciliation proceeding (if approved, Oncor would seek recovery of that regulatory asset in a future Oncor rate case).  On October 8, 2019, Oncor filed a joint motion to admit evidence and for approval of Joint Proposed Order, as agreed to by the PUCT staff and the Steering Committee of Cities. We anticipate that the PUCT will consider the Joint Proposed Order by the first quarter of 2020. We cannot predict the outcome of the proceeding at this time.

Revenues

Revenues	9 Months Ended
	Sep. 30, 2019
Revenues [Abstract]
REVENUES	3. REVENUES  General  Our revenue is billed monthly 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 to customers including a reasonable rate of return on invested capital. As the volumes delivered can be directly measured, our revenues are recognized when the underlying service has been provided in an amount prescribed by the related tariff. We recognize revenue in the amount that we have the right to invoice. Substantially all of our revenues are from contracts with customers except for alternative revenue program revenues discussed below.  Reconcilable Tariffs  The PUCT has designated certain tariffs (primarily TCRF and EECRF) 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.  Alternative Revenue Program  The PUCT has implemented an incentive program allowing us to earn performance bonuses by exceeding PUCT energy efficiency program targets. This incentive program and the related performance bonus revenues are considered an “alternative revenue program” under GAAP. Annual performance bonuses are recognized as revenue when approved by the PUCT, typically in the third or fourth quarter each year.  Disaggregation of Revenues  The following table reflects electric delivery revenues disaggregated by tariff for the three and nine months ended September 30, 2019 and 2018:   Three Months Ended September 30, Nine Months Ended September 30,  2019 2018 2019 2018  Operating revenues  Revenues contributing to earnings:  Distribution base revenues $ 633 $ 604 $ 1,629 $ 1,640  Transmission base revenues (TCOS revenues):  Billed to third-party wholesale customers 181 137 493 403  Billed to REPs serving Oncor distribution customers, through TCRF 105 77 282 234  Total transmission base revenues 286 214 775 637  Other miscellaneous revenues 31 17 66 48  Total revenues contributing to earnings 950 835 2,470 2,325   Revenues collected for pass-through expenses:  TCRF - third-party wholesale transmission service 245 237 759 719  EECRF and other regulatory charges 16 23 39 62  Revenues collected for pass-through expenses 261 260 798 781   Total operating revenues $ 1,211 $ 1,095 $ 3,268 $ 3,106  Customers  Our distribution customers consist of approximately 90 REPs and certain electric cooperatives in our certificated service area. The consumers of the electricity we deliver are free to choose their electricity supplier from REPs who compete for their business. Our transmission base revenues are collected from load serving entities benefiting from our transmission system. Our transmission customers consist of municipalities, electric cooperatives and other distribution companies. REP subsidiaries of our two largest counterparties represent ed 24% and 19% of our total operating revenues for the three months ended September 30, 2019, and 22% and 18% of our total operating revenues for the nine months ended September 30, 2019. No other customer represented more than 10% of our total operating revenues.  Variability  Our revenues and cash flows are subject to seasonality, timing of customer billings, weather conditions and other electricity usage drivers, with revenues being highest in the summer. Payment is due 35 days after invoicing. Under a PUCT rule relating to the Certification of Retail Electric Providers, write-offs of uncollectible amounts owed by REPs are recoverable as a regulatory asset.  Pass-through Expenses  Expenses which are allowed to be passed-through to customers (primarily, third party wholesale transmission service and energy efficiency program costs) are generally recognized as revenue at the time the costs are incurred. Franchise taxes are assessed by local governmental bodies, based on kWh delivered and are not a “pass-through” item. The rates we charge customers are intended to recover the franchise taxes, but we are not acting as an agent to collect the taxes from customers; therefore, franchise taxes are reported as a principal component of “taxes other than amounts related to income taxes” instead of a reduction to “revenues” in the income statement.

Short-Term Borrowings

Short-Term Borrowings	9 Months Ended
	Sep. 30, 2019
Short-Term Borrowings [Abstract]
SHORT-TERM BORROWINGS	4. SHORT-TERM BORROWINGS  At September 30, 2019 and December 31, 2018, outstanding short-term borrowings under our CP Program and Credit Facility consisted of the following:   At September 30, At December 31,  2019 2018  Total borrowing capacity $ 2,000 $ 2,000  Commercial paper outstanding (a) - (813)  Credit facility outstanding (b) - -  Letters of credit outstanding (c) (10) (9)  Available unused credit $ 1,990 $ 1,178 ____________ a) The weighted average interest rate for commercial paper at December 31, 2018 w as 2.74% . b) At September 30, 2019, the applicable interest rate for any outstanding borrowings would have been LIBOR plus 1.00%. c) The interest rate on outstanding letters of credit at both September 30, 2019 and December 31, 2018 was 1.20% based on our credit ratings. CP Program  In March 2018, we established the CP Program, under which we may issue unsecured commercial paper notes ( CP Notes) on a private placement basis up to a maximum aggregate face or principal amount outstanding at any time of $2.0 billion. The proceeds of CP Notes issued under the CP Program are used for working capital and general corporate purposes. The CP Program obtains liquidity support from our Credit Facility , which is discussed below. W e may utilize either the CP Program or th e Credit Facility, at our option, to meet our funding needs.  Credit Facility  At September 30, 2019, we had a $2.0 b illion unsecured Credit Facility to be used for working capital and general corporate purposes, issuances of letters of credit and support for commercial paper issuances . We may request increases in our borrowing capacity in increments of not less than $100 million, not to exceed $400 million in the aggregate provided certain conditions are met, including lender approvals. The Credit Facility’s five -year term expires in November 2022 and gives us the option of requesting up to two one -year extensions, with such extensions subject to certain conditions and lender approvals. Borrowings are classified as short-term on the balance sheet.  May 2019 Short-Term Bridge Loan  On May 9, 2019, we entered into a short-term unsecured term loan credit agreement (Bridge Loan) in an aggregate principal amount of up to $600 million in connection with the InfraREIT Acquisition. The Bridge Loan had a six -month term. B orrowings under the Bridge Loan could only be used to finance the repayment of indebtedness of InfraREIT or its affiliates and to pay expenses and fees related to the InfraREIT Acquisition. A fee was payable to the lenders under the Bridge Loan in an amount equal to 0.075% per annum on the average daily undrawn amount of the commitments.  The Bridge Loan contained 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. The Bridge Loan also contained a senior debt-to-capitalization ratio covenant that effectively limited our ability to incur indebtedness in the future.  On May 15, 2019, we borrowed $600 million under the Bridge Loan to pay, at closing of the InfraREIT Acquisition, all amounts outstanding under SDTS’s term loan, all amounts outstanding under the revolving credit facilities of SDTS and InfraREIT Partners, and amounts owed to discharge certain outstanding notes of InfraREIT’s subsidiaries. The borrowing under the Bridge Loan bore interest at a per annum rate equal to LIBOR plus 0.65% . The Bridge Loan was repaid in full in May 2019 with the proceeds from our May 23, 2019 senior secured notes issuance (discussed in Note 5 below) and as a result the agreement is no longer in effect.  InfraREIT Short-Term Debt Repayments in Connection with InfraREIT Acquisition In connection with the closing of the InfraREIT Acquisition, on May 16, 2019, the credit facilities of InfraREIT and its subsidiaries were terminated and borrowings totaling $114 million were repaid in full by Oncor. For more information on the extinguishment of InfraREIT debt in connection with the InfraREIT Acquisition, see Notes 5 and 11.

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2019
Long-Term Debt [Abstract]
LONG-TERM DEBT	5. 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, 2019 and December 31, 2018, our long-term debt consisted of the following:   September 30, December 31,  2019 2018  Fixed Rate Secured:  2.15% Senior Notes due June 1, 2019 $ - $ 250  5.75% Senior Notes due September 30, 2020 126 126  8.50% Senior Notes, Series C, due December 30, 2020 14 -  4.10% Senior Notes, due June 1, 2022 400 400  7.00% Debentures due September 1, 2022 482 482  2.75% Senior Notes due June 1, 2024 500 -  2.95% Senior Notes due April 1, 2025 350 350  3.86% Senior Notes, Series A, due December 3, 2025 174 -  3.86% Senior Notes, Series B, due January 14, 2026 38 -  3.70% Senior Notes due November 15, 2028 650 350  5.75% Senior Notes due March 15, 2029 318 318  7.25% Senior Notes, Series B, due December 30, 2029 37 -  6.47% Senior Notes, Series A, due September 30, 2030 84 -  7.00% Senior Notes due May 1, 2032 500 500  7.25% Senior Notes due January 15, 2033 350 350  7.50% Senior Notes due September 1, 2038 300 300  5.25% Senior Notes due September 30, 2040 475 475  4.55% Senior Notes due December 1, 2041 400 400  5.30% Senior Notes due June 1, 2042 500 500  3.75% Senior Notes due April 1, 2045 550 550  3.80% Senior Notes due September 30, 2047 325 325  4.10% Senior Notes due November 15, 2048 450 450  3.80% Senior Notes, due June 1, 2049 500 -  3.10% Senior Notes, due September 15, 2049 700 -  Secured long-term debt 8,223 6,126  Unsecured:  Term loan credit agreement maturing December 9, 2019 350 350  Term loan credit agreement maturing October 6, 2020 460 -  Total long-term debt 9,033 6,476  Unamortized discount and debt issuance costs (57) (41)  Less amount due currently (485) (600)  Long-term debt, less amounts due currently $ 8,491 $ 5,835 Long-Term Debt-Related Activity in 2019  Long-Term Debt Activity in Connection with InfraREIT Acquisition  In connection with the closing of the InfraREIT Acquisition, on May 16, 2019, we extinguished all of the $839 million of outstanding long-term debt of InfraREIT and its subsidiaries through repayment of $288 million principal amount of outstanding InfraREIT subsidiary senior notes (plus $5 million in accrued interest and $19 million in make-whole fees relating to those notes ) , repayment of a n o utstanding $200 million principal amount InfraREIT subsidiary term loan and the exchange of $351 million principal amount of outstanding InfraREIT subsidiary senior notes for a like principal amount of new ly issued Oncor secured senior notes. We received no proceeds from the issuance of the new Oncor notes and the exchanges were accoun ted for as debt modifications. Following are details of the exchanges:  (i) $87 million aggregate principal amount of newly issued Oncor 6.47% Senior Notes, Series A, due September 30, 2030 (2030 Notes), issued in exchange for a like principal amount of SDTS’s 6.47% Senior Notes due September 30, 2030, (ii) $38 million aggregate principal amount of newly issued Oncor 7.25% Senior Notes, Series B, due December 30, 2029 (2029 Notes), issued in exchange for a like principal amount of SDTS’s 7.25% Senior Notes due December 30, 2029, (iii) $14 million aggregate principal amount of newly issued Oncor 8.50% Senior Notes, Series C, due December 30, 2020 (2020 Notes), issued in exchange for a like principal amount of Transmission and Distributions Company, L.L.C.’s 8.5% Senior Notes due December 30, 2020, (iv) $174 million aggregate principal amount of newly issued Oncor 3.86% Senior Notes, Series A, due December 3, 2025 (2025 Notes), issued in exchange for a like principal amount of SDTS’s 3.86% Senior Notes due December 3, 2025, and (v) $38 million aggregate principal amount of newly issued Oncor 3.86% Senior Notes, Series B, due January 14, 2026 (2026 Notes), issued in exchange for a like principal amount of SDTS’s 3.86% Senior Notes due January 14, 2026.  The 2030 Notes, 2029 Notes and 2020 Notes were issued pursuant to a note purchase agreement (ABC Note Purchase Agreement) that we entered into on May 3, 2019. The 2025 Notes and 2026 Notes were issued pursuant to a note purchase agreement (AB Note Purchase Agreement, and together with the ABC Note Purchase Agreement, Note Purchase Agreements) that we entered into on May 6, 2019. Closing of the Note Purchase Agreements and issuance of the 2030 Notes, 2029 Notes, 2020 Notes, 2025 Notes and 2026 Notes (collectively, NPA Notes) occurred on May 16, 2019, immediately following consummation of the InfraREIT Acquisition.  At closing of the Note Purchase Agreements, we paid accrued and unpaid interest and certain fees with respect to the exchanged notes totaling an aggregate of $6 million.  The Note Purchase Agreements contain customary covenant restrictions and events of default. The NPA Notes are secured equally and ratably with our other secured indebtedness pursuant to the Deed of Trust. For more information on the Deed of Trust, see “Deed of Trust” below. We received no proceeds from the issuance of the NPA Notes.  Additional Debt Repayments  Repayments of long-term debt in the nine months ended September 30, 2019 included $250 million aggregate principal amount of our 2.15% senior secured notes due June 1, 2019 , $488 million aggregate principal amount of long-term debt of InfraREIT’s subsidiaries that we paid on May 16, 2019 in connection with and immediately following the InfraREIT Acquisition and $4 million principal amount of the quarterly amortizing debt for our 2020 Notes, 2029 Notes and 2030 Notes.  Additional Long-Term Debt Issuances  On September 12, 2019, we completed a sale of $700 million aggregate principal amount of 3.10% Senior Secured Notes due September 15, 2049 (3.10% 2049 Notes). We used the proceeds (net of the initial purchasers’ discount, fees and expenses) of $689 million from the sale of the 3.10% 2049 Notes for general corporate purposes, including to repay CP Notes, when due, under our CP Program. I nterest and the applicable principal repayment for the 3.10% 2049 Notes are payable on the 15th day of March and September of each year, beginning March 15, 2020.  On May 23, 2019, we completed a sale of $500 million aggregate principal amount of 2.75% Senior Secured Notes due 2024 (2024 Notes), $300 million aggregate principal amount of 3.70% Senior Secured Notes due 2028 (2028 Notes) and $500 million aggregate principal amount of 3.80% Senior Secured Notes due 2049 ( 3.80% 2049 Notes and, together with the 2024 Notes and the 2028 Notes, the New Indenture Notes). The 2028 Notes constitute an additional issuance of our 3.70% Senior Secured Notes due 2028, $350 million of which we previously issued on August 10, 2018 and are currently outstanding (Outstanding Notes). The 2028 Notes were issued as part of the same series as the Outstanding Notes. Additionally, the 2028 Notes exchanged or sold in connection with the transactions contemplated by a registration rights agreement are expected to become fungible with the Outstanding Notes. We used the proceeds (net of the initial purchasers’ discount, fees, expenses and accrued interest) of $1,297 million from the sale of the New Indenture Notes for general corporate purposes, including to repay all amounts outstanding under the Bridge Loan, to repay our $250 million aggregate principal amount of 2.15% Senior Secured Notes due June 1, 2019 and to repay CP Notes, when due, under our CP Program. For more information on the Bridge Loan, see Note 4.  The New Indenture Notes and 3.10% 2049 Notes were issued in separate private placements 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 New Indenture Notes and 3.10% 2049 Notes (except for provisions relating to the transfer restriction and payment of additional interest) as part of our offers to exchange freely tradable exchange notes for the New Indenture Notes and 3.10% 2049 Notes. We have agreed to use commercially reasonable efforts to cause the exchange offers to be completed within 315 days after the applicable issue date of the New Indenture Notes and 3.10% 2049 Notes. If a registration statement for the exchange offers is not declared effective by the SEC within 270 days after the applicable issue date of the New Indenture Notes and 3.10% 2049 Notes or the exchange offers are not completed within 315 days after the applicable issue date of the New Indenture Notes and 3.10% 2049 Notes (an exchange default), then the annual interest rate on the New Indenture Notes and 3.10% 2049 Notes, as applicable, will increase 50 basis points per annum until the earlier of the expiration of the exchange default or the second anniversary of the applicable issue dates of the New Indenture Notes and 3.10% 2049 Notes. The registration statement for the exchange offers was declared effective by the SEC on October 17, 2019, which was within 270 days of the applicable issue date of the New Indenture Notes and the 3.10% 2049 Notes.  September 2019 Term Loan Credit Agreement  On September 6, 2019, we entered into an unsecured term loan credit agreement (2019 Term Loan Agreement) in an aggregate principal amount of up to $460 million. The agreement has a 13-month term, maturing on October 6, 2020. We borrowed the full aggregate principal amount available under the 2019 Term Loan Agreement of $460 million on September 25, 2019. The term loan bears interest at per annum rates equal to, at Oncor’s option, (i) LIBOR plus 0.50% , or (ii) an alternate base rate (the highest of (1) the prime rate of Wells Fargo, (2) the federal funds effective rate plus 0.50% , and (3) daily one-month LIBOR plus 1% ). We used the proceeds (net of fees and expenses) for general corporate purposes, including to repay CP Notes, when due, under our CP program.  Deed of Trust  Our secured indebtedness 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 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, 2019, the amount of available bond credits was $2,784 million and the amount of future debt we could secure with property additions, subject to those property additions being certified to the Deed of Trust collateral agent, was $1,942 million.  Borrowings under the CP Program, the Credit Facility, and our term loan credit agreements are not secured.  Maturities  Long-term maturities (including current maturities) at September 30, 2019, are as follows:    Year Amount  2019 $ 485  2020 481  2021 9  2022 891  2023 10  Thereafter 7,157  Unamortized discount and debt issuance costs (57)  Total $ 8,976  Fair Value of Long-Term Debt  At September 30, 2019 and December 31, 2018, the estimated fair value of our long-term debt (including current maturities) totaled $10,477 million and $7,086 million, respectively, and the carrying amount totaled $8,976 million and $6,435 million, 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, 2019
Commitments and Contingencies [Abstract]
COMMITMENTS AND CONTINGENCIES	6. COMMITMENTS AND CONTINGENCIES  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 Notes 2, 8 and 11 to Financial Statements in our 2018 Form 10-K for additional information regarding our regulatory and legal proceedings, respectively.  Leases  General  A lease exists when a contract conveys the right to control the use of an identified asset for a period of time in exchange for consideration. As lessee, our leased assets primarily consist of our vehicle fleet and real estate leased for company offices and service centers. Our leases are accounted for as operating leases for both GAAP and rate-making purposes. We generally recognize operating lease costs on a straight-line basis over the lease term in operating expenses. We are not a lessor to any material lease contracts.  As of the lease commencement date, we recognize a lease liability for our obligation to make lease payments, which we initially measure at present value using our incremental borrowing rate at the date of lease commencement, unless the rate implicit in the lease is readily determinable. We determine our incremental borrowing rate based on the rate of interest that we would have to pay to borrow on a collateralized basis over a similar term an amount equal to the lease payments in a similar economic environment. We also record a ROU asset for our right to use the underlying asset, which is initially equal to the lease liability and adjusted for any lease payments made at or before lease commencement, lease incentives and any initial direct costs.  Some of our lease agreements contain nonlease components, which represent items or activities that transfer a good or service. We separate lease components from nonlease components, if any, for our fleet vehicle and real estate leases for purposes of calculating the related lease liability and ROU asset.  Certain of our leases include options to extend the lease terms for up to 20 years, while others include options to terminate early. Our lease liabilities and ROU assets are based on lease terms that may include such options to extend or terminate the lease when it is reasonably certain that we will exercise that option.  Short-term Leases  Some of our contracts are short-term leases, which have a lease term of 12 months or less at lease commencement. As allowed by GAAP, we do not recognize a lease liability or ROU asset arising from short-term leases for all existing classes of underlying assets. We recognize short-term lease costs on a straight-line basis over the lease term.  Lease Obligations, Lease Costs and Other Supplemental Data  The following tables summarize lease information as of and for the nine months ended September 30, 2019 .    At September 30,  2019  Operating Leases:  ROU assets:  Operating lease ROU assets and other $ 88   Lease liabilities:  Operating lease and other current liabilities $ 25  Employee benefit, operating lease and other obligations 63  Total operating lease liabilities $ 88   Weighted-average remaining lease term (in years) 4  Weighted-average discount rate 3.4%  The components of lease costs and cash paid for amounts included in the measurement of lease liabilities for the three and nine months ended September 30, 2019 were as follows:   Three Months Ended Nine Months Ended  September 30, 2019 September 30, 2019  Operating lease cost:  Operating lease costs (including amounts allocated to property, plant and equipment) $ 10 $ 29  Short-term lease costs 9 32  Total operating lease costs $ 19 $ 61   Operating lease payments:  Cash paid for amounts included in the measurement of lease liabilities $ 8 $ 23  The table below presents the maturity analysis of our lease liabilities and reconciliation to the present value of lease liabilities:    Year Amount  2019 (remaining three months) $ 8  2020 25  2021 23  2022 17  2023 10  Thereafter 9  Total undiscounted lease payments 92  Less imputed interest (4)  Total future minimum lease payments $ 88  Lease Disclosures Under Previous GAAP  The table below presents the future minimum lease payments as of December 31, 2018 under previous GAAP:    Year Amount  2019 $ 29  2020 22  2021 20  2022 15  2023 8  Thereafter 5  Total future minimum lease payments $ 99 

Membership Interests

Membership Interests	9 Months Ended
	Sep. 30, 2019
Membership Interests [Abstract]
MEMBERSHIP INTERESTS	 7. MEMBERSHIP INTERESTS  Cash Contributions   On October 28, 2019, our members made capital contributions in an aggregate amount of $98 million. In May 2019, Sempra and certain indirect equity holders of Texas Transmission made capital contributions in an aggregate amount of $1,330 million to fund the cash consideration and certain expenses payable in connection with the InfraREIT Acquisition. For more information on the InfraREIT Acquisition, see Note 11.  The f ollowing is a summary of cash contributions Oncor received during the nine months ended September 30, 2019.   Payment Date Amount  July 29, 2019 $ 70  May 15, 2019 1,330  April 30, 2019 70  February 19, 2019 70  Cash Distributions   The PUCT order issued in the Sempra Acquisition and our limited liability company agreement set forth various restrictions on distributions to our members. Among those restrictions is the commitment that we will make no distributions that would cause us to be out of compliance with the PUCT’s approved debt-to-equity ratio, which is currently 57.5% debt to 42.5% equity. The distribution restrictions also include the ability of our board, a majority of the disinterested directors, or any Texas Transmission director to limit distributions to the extent each determines it is necessary to meet expected future requirements of Oncor (including continuing compliance with the PUCT debt-to-equity ratio commitment). At September 30, 2019, we had $27 million available to distribute to our members as our regulatory capitalization ratio was 57.4% debt to 42.6% equity.  The PUCT has the authority to determine what types of debt and equity are included in a utility’s debt-to-equity ratio. For purposes of this ratio, debt is calculated as long-term debt including finance 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 from a 2007 transaction.  On October 29 , 2019, based on the amount available for distribution on such date, our board of directors declared a cash distribution of $106 million, which was paid to our members on October 31 , 2019. During the nine months ended September 30, 2019, our board of directors declared and we paid the following cash distributions to our members:    Declaration Date Payment Date Amount  July 30, 2019 July 31, 2019 $ 71  May 1, 2019 May 2, 2019 71  February 20, 2019 February 22, 2019 71  Membership Interests  The following tables present the changes to membership interests during the three months and nine months ended September 30, 2019 and 2018, net of tax:    Capital Accounts Accumulated Other Comprehensive Income (Loss) Total Membership Interests  Three Months Ended September 30, 2019  Balance at June 30, 2019 $ 10,210 $ (164) $ 10,046  Net income 263 - 263  Distributions (71) - (71)  Capital contributions 70 - 70  Net effects of cash flow hedges - 1 1  Defined benefit pension plans - 2 2  Balance at September 30, 2019 $ 10,472 $ (161) $ 10,311         Capital Accounts Accumulated Other Comprehensive Income (Loss) Total Membership Interests  Three Months Ended September 30, 2018  Balance at June 30, 2018 $ 8,380 $ (99) $ 8,281  Net income 194 - 194  Distributions (30) - (30)  Net effects of cash flow hedges - 2 2  Balance at September 30, 2018 $ 8,544 $ (97) $ 8,447     Capital Accounts Accumulated Other Comprehensive Income (Loss) Total Membership Interests  Nine Months Ended September 30, 2019  Balance at December 31, 2018 $ 8,624 $ (164) $ 8,460  Net income 518 - 518  Distributions (213) - (213)  Capital contributions 1,540 - 1,540  Net effects of cash flow hedges (Note 1) 3 (1) 2  Defined benefit pension plans - 4 4  Balance at September 30, 2019 $ 10,472 $ (161) $ 10,311     Capital Accounts Accumulated Other Comprehensive Income (Loss) Total Membership Interests  Nine Months Ended September 30, 2018  Balance at December 31, 2017 $ 8,004 $ (101) $ 7,903  Net income 426 - 426  Distributions (30) - (30)  Capital contributions 144 - 144  Net effects of cash flow hedges - 2 2  Defined benefit pension plans - 2 2  Balance at September 30, 2018 $ 8,544 $ (97) $ 8,447       Accumulated Other Comprehensive Income (Loss)  The following table presents the changes to accumulated other comprehensive income (loss) for the nine months ended September 30, 2019 and 2018, net of tax:   Cash Flow Hedges – Interest Rate Swap Defined Benefit Pension and OPEB Plans Accumulated Other Comprehensive Income (Loss)  Balance at December 31, 2018 $ (16) $ (148) $ (164)  Defined benefit pension plans - 5 5  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Amounts reclassified from accumulated other comprehensive income (loss) to capital account (Note 1) (4) - (4)  Balance at September 30, 2019 $ (18) $ (143) $ (161)   Balance at December 31, 2017 $ (18) $ (83) $ (101)  Defined benefit pension plans - 2 2  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at September 30, 2018 $ (16) $ (81) $ (97) 

Pension and OPEB Plans

Pension and OPEB Plans	9 Months Ended
	Sep. 30, 2019
Pension and OPEB Plans [Abstract]
PENSION AND OPEB PLANS	8. 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 2018 Form 10-K for additional information regarding pension plans.  OPEB Plans  We currently sponsor two OPEB plans. One plan covers our eligible current and future retirees whose services are 100% attributed to the regulated business. Effective January 1, 2018, we established a second plan to cover EFH Corp./Vistra retirees and eligible current and future retirees whose employment services were assigned to both Oncor (or a predecessor regulated utility business) and the non-regulated business of EFH Corp./Vistra. Vistra is solely responsible for its portion of the liability for retiree benefits related to those retirees. See Note 10 to Financial Statements in our 2018 Form 10-K for additional information.  Pension and OPEB Costs  Our net costs related to pension plans and the Oncor OPEB Plans for the three and nine months ended September 30, 2019 and 2018 were comprised of the following:   Three Months Ended September 30, Nine Months Ended September 30,  2019 2018 2019 2018   Components of net allocated pension costs:  Service cost $ 6 $ 7 $ 19 $ 21  Interest cost 32 29 96 89  Expected return on assets (29) (29) (89) (89)  Amortization of net loss 7 12 22 36  Net pension costs 16 19 48 57  Components of net OPEB costs:  Service cost 2 2 5 6  Interest cost 10 11 32 33  Expected return on assets (2) (2) (6) (6)  Amortization of prior service cost (5) (8) (15) (21)  Amortization of net loss 5 14 14 41  Net OPEB costs 10 17 30 53  Total net pension and OPEB costs 26 36 78 110  Less amounts deferred principally as property or a regulatory asset (7) (17) (20) (52)  Net amounts recognized as operation and maintenance expense or other deductions $ 19 $ 19 $ 58 $ 58  The discount rates reflected in net pension and OPEB costs in 2019 are 4.16% , 4.40% and 4.41% for the Oncor Retirement Plan, the Vistra Retirement Plan and the Oncor OPEB Plans, respectively. The expected return on pension and OPEB plan assets reflected in the 2019 cost amounts are 5.43% , 5.29% and 6.19% for the Oncor Retirement Plan, the Vistra Retirement Plan and the Oncor OPEB Plans, respectively.  Pension and OPEB Plans Cash Contributions  We made cash contributions to the pension plans and Oncor OPEB Plans of $26 million and $26 million, respectively, during the nine months ended September 30, 2019. We expect to make additional cash contributions to the pension plans and Oncor OPEB Plans of $15 million and $9 million, respectively, during the remainder of 2019. Our aggregate pension plans and Oncor OPEB Plans funding is expected to total approximately $5 27 million and $17 5 million, respectively, in the 2019 to 2023 period based on the latest actuarial projections.

Related-Party Transactions

Related-Party Transactions	9 Months Ended
	Sep. 30, 2019
Related-Party Transactions [Abstract]
RELATED-PARTY TRANSACTIONS	9. RELATED-PARTY TRANSACTIONS  The following represent our significant related-party transactions. As a result of the Sempra Acquisition, Sempra became a related party and the Sponsor Group ceased to be a related party as of March 9, 2018. In addition, as of the May 16, 2019 closing of the Sempra-Sharyland Transaction, Sharyland became a related party.  · We are not a member of another entity’s consolidated tax group, but our owners’ federal income tax returns include their portion of our results. Under the terms of a tax sharing agreement among us, Oncor Holdings, Texas Transmission and STH (as successor to EFH Corp.), we are generally obligated to make payments to our owners, 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. STH will file a combined Texas margin tax return that includes our results and our share of 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 2018 Form 10-K under “Provision in Lieu of Income Taxes.” Under the “in lieu of” tax concept, all in lieu of tax assets and tax liabilities represent amounts that will eventually be settled with our members. In the event such amounts are not paid under the tax sharing agreement, it is probable that this regulatory liability will continue to be included in Oncor’s rate setting processes.  Amounts payable to (receivable from) members related to income taxes under the tax sharing agreement and reported on our balance sheets consisted of the following:   At September 30, 2019 At December 31, 2018  STH Texas Transmission Total STH Texas Transmission Total   Federal income taxes payable (receivable) $ 10 $ 2 $ 12 $ 4 $ 1 $ 5  Texas margin taxes payable 17 - 17 21 - 21  Net payable (receivable) $ 27 $ 2 $ 29 $ 25 $ 1 $ 26  Cash payments made to (received from) members related to income taxes consisted of the following:    Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018  STH Texas Transmission Total STH EFH Corp. Texas Transmission Total   Federal income taxes $ 29 $ 7 $ 36 $ 41 $ (19) $ 6 $ 28  Texas margin taxes 22 - 22 21 - - 21  Total payments (receipts) $ 51 $ 7 $ 58 $ 62 $ (19) $ 6 $ 49 See Note 7 for information regarding distributions to and capital contributions from members, including an aggregate of $1,330 million in capital contributions received from members to fund the InfraREIT Acquisition and certain expenses.  · From the May 16, 2019 InfraREIT Acquisition date through September 30, 2019, Sharyland provided wholesale transmission service to us in the amount of $5 million and we provided Sharyland with substation monitoring and switching services of less than $1 million.

Supplementary Financial Informa

Supplementary Financial Information	9 Months Ended
	Sep. 30, 2019
Supplementary Financial Information [Abstract]
SUPPLEMENTARY FINANCIAL INFORMATION	10. SUPPLEMENTARY FINANCIAL INFORMATION  Other Deductions and (Income)   Three Months Ended September 30, Nine Months Ended September 30,  2019 2018 2019 2018   Professional fees $ 2 $ - $ 6 $ 4  Sempra Acquisition related costs - - - 16  InfraREIT Acquisition related costs - - 9 -  Recoverable pension and OPEB - non-service costs 14 13 42 40  Non-recoverable pension and OPEB costs (Note 8) 1 1 3 4  Other, including interest income (3) (1) (4) (1)  Total other deductions and (income) - net $ 14 $ 13 $ 56 $ 63  Interest Expense and Related Charges   Three Months Ended September 30, Nine Months Ended September 30,  2019 2018 2019 2018   Interest $ 98 $ 90 $ 280 $ 268  Amortization of debt issuance costs and discounts 3 2 7 5  Less allowance for funds used during construction – capitalized interest portion (4) (3) (11) (9)  Total interest expense and related charges $ 97 $ 89 $ 276 $ 264  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,  2019 2018   Gross trade accounts and other receivables $ 788 $ 562  Allowance for uncollectible accounts (4) (3)  Trade accounts receivable – net $ 784 $ 559  At September 30, 2019, REP subsidiaries of our two largest customers represented 16% and 14% of the trade receivable balance, respectively. A t December 31, 2018, REP subsidiaries of our two largest counterparties represented 13% and 10% of the tra de accounts receivable balance, respectively.  Under a PUCT rule relating to the Certification of Retail Electric Providers, write-offs of uncollectible amounts owed by REPs are deferred as a regulatory asset.  Investments and Other Property  Investments and other property reported on our balance sheets consisted of the following:    At September 30, At December 31,  2019 2018   Assets related to employee benefit plans, including employee savings programs $ 113 $ 108  Land 12 12  Other 2 -  Total investments and other property $ 127 $ 120 Property, Plant and Equipment  Property, plant and equipment - net reported on our balance sheets consisted of the following. Property, plant and equipment - net at September 30, 2019 includes an increase of approximately $1,800 million due to the InfraREIT Acquisition:   Composite Depreciation Rate/ At September 30, At December 31,  Avg. Life at September 30, 2019 2019 2018  Assets in service:  Distribution 2.8% / 35.7 years $ 13,833 $ 13,105  Transmission 2.8% / 35.1 years 10,681 8,568  Other assets 6.9% / 14.5 years 1,546 1,497  Total 26,060 23,170  Less accumulated depreciation 7,949 7,513  Net of accumulated depreciation 18,111 15,657  Construction work in progress 843 417  Held for future use 19 16  Property, plant and equipment – net $ 18,973 $ 16,090  Intangible Assets  Intangible assets (other than goodwill) reported on our balance sheets as part of property, plant and equipment consisted of the following:   At September 30, 2019 At December 31, 2018  Gross Gross  Carrying Accumulated Carrying Accumulated  Amount Amortization Net Amount Amortization Net   Identifiable intangible assets subject to amortization:  Land easements $ 559 $ 106 $ 453 $ 464 $ 101 $ 363  Capitalized software 806 422 384 787 385 402  Total $ 1,365 $ 528 $ 837 $ 1,251 $ 486 $ 765  A ggregate amortization expenses for intangible assets totaled $13 million for both of the three months ended September 30, 2019 and 2018 and $39 million for each of the nine months ended September 30, 2019 and 2018 . The estimated aggregate amortization expense for each of the next five fiscal years is as follows:   Year Amortization Expense  2019 $ 52  2020 52  2021 52  2022 52  2023 51  Employee Benefit, Operating Lease and Other Obligations  Employee benefit, operating lease and other obligations reported on our balance sheet consisted of the following:   At September 30, At December 31,  2019 2018   Retirement plans and other employee benefits 1,854 $ 1,858  Operating lease liabilities 62 -  Investment tax credits 7 8  Other 82 77  Total employee benefit, operating lease and other obligations $ 2,005 $ 1,943  Supplemental Cash Flow Information   Nine Months Ended September 30,  2019 2018   Cash payments (receipts) related to:  Interest $ 256 $ 243  Less capitalized interest (11) (9)  Interest payments (net of amounts capitalized) $ 245 $ 234  Amount in lieu of income taxes (a):  Federal $ 36 $ 28  State 22 21  Total payments (receipts) in lieu of income taxes $ 58 $ 49   Noncash increase in operating lease obligations for ROU assets $ 26 $ -   Noncash investing and financing activity (b):  Acquisition:  Assets acquired 2,545 $ -  Liabilities assumed (1,221) -  Cash paid $ 1,324 $ -   Noncash construction expenditures (c) $ 257 $ 136 ____________ (a) See Note 9 for income tax related detail. (b) See Note 5 for more information on noncash debt exchanges related to InfraREIT Acquisition. (c) Represents end-of-period accruals .

Infrareit Acquisition

Infrareit Acquisition	9 Months Ended
	Sep. 30, 2019
Infrareit Acquisition [Abstract]
INFRAREIT ACQUISITION	11. INFRAREIT ACQUISITION  On May 16, 2019, we completed the InfraREIT Acquisition, pursuant to which we acquired all of the equity interests of InfraREIT and its subsidiary, InfraREIT Partners. The InfraREIT Acquisition occurred through the merger of InfraREIT with and into a newly formed wholly owned subsidiary of Oncor, followed by the merger of another newly formed wholly owned subsidiary of Oncor with and into InfraREIT Partners. The stockholders of InfraREIT and the limited partners of InfraREIT Partners received $21.00 in cash per share of common stock or limited partnership unit, as applicable, resulting in a total cash consideration of $1,275 million . In addition , we paid certain transaction costs incurred by InfraREIT (including a management agreement termination fee of $40 million that InfraREIT paid an affiliate of Hunt Consolidated, Inc. at closing), with the aggregate cash consideration and payment of InfraREIT expenses totaling $1,32 4 million.  In connection with and immediately following the closing of the InfraREIT Acquisition, on May 16, 2019, we extinguished all outstanding debt of InfraREIT and its subsidiaries through repaying $602 million principal amount of InfraREIT subsidiary debt and exchanging $351 million principal amount of InfraREIT subsidiary debt for new Oncor senior secured debt, as discussed in more detail in Notes 4 and 5.  On May 15, 2019, in connection with the InfraREIT Acquisition, we received capital contributions in an aggregate amount of $1,330 million from Sempra and certain indirect equity holders of Texas Transmission to fund the cash consideration and certain transaction expenses. As a condition to the InfraREIT Acquisition, SDTS, and SDTS’s tenant, SU, completed the SDTS-SU Asset Exchange immediately prior to the closing of the InfraREIT Acquisition, pursuant to which SDTS exchanged certain of its south Texas assets for certain north Texas assets owned by SU. The north Texas assets acquired by SDTS consisted of certain real property and other assets owned by SU and used in the electric transmission and distribution business in c entral, n orth and w est Texas, as well as equity interests in GS Project Entity, L.L.C., a Texas limited liability company that was merged with and into SDTS. The south Texas assets acquired by SU consisted of real property and other assets near the Texas-Mexico border. As a result of the InfraREIT Acquisition closing, we and our subsidiary NTU now own all of the assets and projects in the north, central, west and panhandle regions of Texas held by SDTS and SU immediately prior to the InfraREIT Acquisition, and Sharyland owns the assets that were held by SU and SDTS in south Texas immediately prior to the InfraREIT Acquisition. The assets we acquired include approximately 1,575 miles of transmission lines, including 1,235 circuit miles of 345k V transmission lines and approximately 340 circuit miles of 138kV transmission lines. The north, central, and west Texas transmission system acquired by us in the transaction is directly connected to approximately 20 operational generation facilities totaling approximately 3,900 MW and serves over 50 substations. In addition, as a condition to the closing of the SDTS-SU Asset Exchange, Sempra acquired an indirect 50 percent interest in Sharyland Holdings, the parent of Sharyland , in the Sempra-Sharyland Transaction. As a result of the Sempra-Sharyland Transaction, Sharyland is now our affiliate for purposes of PUCT rules. Pursuant to the agreement governing the SDTS-SU Asset Exchange and the PUCT order in Docket No. 48929 approving the InfraREIT Acquisition, upon closing of the InfraREIT Acquisition we entered into an operation agreement pursuant to which we will provide certain operations services to Sharyland at cost with no markup or profit.  Business Combination Accounting  We accounted for the InfraREIT Acquisition as a business acquisition with identifiable assets acquired and liabilities assumed recorded at their estimated fair values on the closing date. The combined results of operations are reported in our consolidated financial statements beginning as of the closing date. A summary of techniques used to estimate the preliminary fair value of the identifiable assets and liabilities is listed below.  · Assets and liabilities that are included in the PUCT cost-based regulatory rate-setting processes are recorded at fair values equal to their regulatory carrying value consistent with GAAP and industry practice. · Working capital was valued using market information (Level 2).  The following tables set forth the purchase price paid and the allocation of the total purchase price paid to the identifiable assets acquired and liabilities assumed. The purchase price allocation is preliminary and the allocation to each identifiable asset acquired and liability assumed may change based upon the receipt of more detailed information and additional analyses related primarily to deferred tax liabilities. In the three months ended September 30, 2019, we made various purchase price allocation adjustments related primarily to working capital accounts resulting in a $12 million reduction to goodwill. We currently expect the final purchase price allocation will be completed no later than the second quarter of 2020.    The total purchase price paid was comprised of the following   Purchase of outstanding InfraREIT shares and units $ 1,275  Certain transaction costs of InfraREIT paid by Oncor (a) 49  Total purchase price paid $ 1,324 __________________ (a) Represents certain transaction costs incurred by InfraREIT in connection with the transaction and paid by Oncor, including a $40 million management termination fee payable to an affiliate of Hunt Consolidated, Inc.   Purchase price allocation is as follows:  As of May 16, 2019  Assets acquired:  Current assets $ 44  Property, plant and equipment - net 1,800  Goodwill 675  Regulatory assets 16  Other noncurrent assets 10  Total assets acquired 2,545   Liabilities assumed:  Short-term debt 114  Other current liabilities 22  Regulatory liabilities 148  Liability in lieu of deferred income taxes 98  Long-term debt, including due currently 839  Total liabilities assumed 1,221  Net assets acquired 1,324  Total purchase price paid $ 1,324  The goodwill of $6 75 million arising from the InfraREIT Acquisition is attributable to t he assets acquired, which expand our transmission footprint and help us support ERCOT market growth. None of the goodwill is recoverable nor provides a tax benefit in the rate-making process. We did not assume any employee benefit obligations in the acquisition.  Acquisition costs incurred in the InfraREIT Acquisition by Oncor and recorded to other deductions totaled $9 million for the nine months ended September 30, 2019. Our condensed statements of consolidated income include revenues and net income of the acquired business totaling $93 million and $36 million, respectively, since the May 16, 2019 acquisition date.  Unaudited Pro Forma Financial Information  The following unaudited pro forma financial information for the nine months ended September 30, 2019 and 2018 assumes that the InfraREIT Acquisition occurred on January 1, 2018. The unaudited pro forma financial information is provided for information purposes only and is not necessarily indicative of the results of operations that would have occurred had the InfraREIT Acquisition been completed on January 1, 2018, nor is the unaudited pro forma financial information indicative of future results of operations, which may differ materially from the pro forma financial information presented here.   Nine Months Ended September 30,  2019 2018  Oncor Consolidated Pro Forma Revenues $ 3,352 $ 3,268  The unaudited pro forma financial information above excludes pro forma earnings due to the impracticability of a calculation. The acquiree previously operated under a real estate investment trust structure with a unique cost structure and unique federal tax attributes. An accurate retrospective application cannot be objectively and reliably calculated as the new cost structure and new tax attributes would require a significant amount of estimates and judgments.

Business and Significant Acco_2

Business and Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
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 subsidiaries. See “Glossary” for definition of terms and abbreviations.  We are a regulated electricity transmission and distribution company primarily engaged in providing delivery services to REPs that sell power in the north-central, eastern, western and panhandle regions of Texas. We are a direct, majority-owned subsidiary of Oncor Holdings, which is indirectly wholly owned by Sempra. Oncor Holdings owns 80.25% of our membership interests and Texas Transmission owns 19.75% of our membership interests. We are managed as an integrated business; consequently, there are no separate reportable business segments.  Our consolidated financial statements include the results of our wholly owned indirect subsidiary , NTU, which is a regulated utility that provides electricity transmission delivery service in the north-central , western and panhandle regions of Texas. We acquired NTU as part of the InfraREIT Acquisition that closed on May 16, 2019.  Various “ring-fencing” measures have been taken to enhance our credit quality and the separateness between the Oncor Ring-Fenced Entities, Sempra and its affiliates (other than the Oncor Ring-Fenced Entities), and any other entities with a direct or indirect ownership interest in Oncor or Oncor Holdings. These measures serve to mitigate the Oncor Ring-Fenced Entities’ credit exposure to Sempra and its affiliates and any other direct or indirect owners of Oncor and Oncor Holdings, and to reduce the risk that the assets and liabilities of Oncor Ring-Fenced Entities would be substantively consolidated with the assets and liabilities of any Sempra entity or any other direct or indirect owners of Oncor and Oncor Holdings in connection with a bankruptcy of any such entities. Such measures include, among other things: the 19.75% equity interest held by Texas Transmission; maintenance of separate books and records for the Oncor Ring-Fenced Entities; and our board of directors being comprised of a majority of directors who meet certain independent/disinterested director standards. As a result, none of the assets of the Oncor Ring-Fenced Entities are available to satisfy the debt or obligations of any Sempra entity or any other direct or indirect owner of Oncor or Oncor Holdings. The assets and liabilities of the Oncor Ring-Fenced Entities are separate and distinct from those of any Sempra entities and any other direct or indirect owner of Oncor or Oncor Holdings. We do not bear any liability for debt or contractual obligations of Sempra and its affiliates or any other direct or indirect owner of Oncor or Oncor Holdings, and vice versa. Accordingly, our operations are conducted, and our cash flows are managed, independently from Sempra and its affiliates and any other direct or indirect owner of Oncor or Oncor Holdings.
Basis Of Presentation	Basis of Presentation  These unaudited condensed consolidated financial statements should be read in conjunction with the audited financial statements and related notes included in our 2018 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. We have evaluated all subsequent events through the date the financial statements were issued. All appropriate 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 (see Note 13 to Financial Statements in our 2018 Form 10-K for additional information regarding quarterly results of operations). Our consolidated financial statements have been prepared in accordance with GAAP governing rate-regulated operations. All dollar amounts in the financial statements and tables in the notes are stated in millions of U.S. dollars unless otherwise indicated.
Use Of Estimates	Use of Estimates  Preparation of our financial statements requires management to make estimates and assumptions about future events that affect the reporting of assets and liabilities at the balance sheet dates and the reported amounts of revenue and expense, including fair value measurements. In the event estimates and/or assumptions prove to be different from actual amounts, adjustments are made in subsequent periods to reflect more current information. No material adjustments were made to previous estimates or assumptions during the current period.
Goodwill	Goodwill  We discuss goodwill in Note 1 to Financial Statements in our 2018 Form 10-K. The increase in goodwill from $4,064 million at December 31, 2018 to $4,7 39 million at September 30, 2019 is due to the InfraREIT Acquisition. See Note 11 for more information on the InfraREIT Acquisition.
Changes In Accounting Standards	Changes in Accounting Standards  Topic 842, “Leases” – In February 2016, the FASB issued ASU 2016-02 which created FASB Topic 842, Leases (Topic 842). Topic 842 amends previous GAAP to require the balance sheet recognition of substantially all lease assets and liabilities, including operating leases. Operating lease liabilities are not classified as debt for GAAP purposes under Topic 842 and are not treated as debt for our regulatory purposes. All of Oncor’s existing leases meet the definition of an operating lease. Under the new rules, the recognition of any finance leases (previously known as capital leases) on the balance sheet are classified as debt for both GAAP and regulatory capital structure purposes (see Note 7 for details) similar to the previous capital lease treatment.  We adopted Topic 842 on January 1, 2019, using the optional transition method to apply the new guidance prospectively and not restate comparative periods. We elected the package of practical expedients that permits us to not reassess (a) whether a contract is or contains a lease, (b) lease classification or (c) determination of initial direct costs, which allows us to carry forward accounting conclusions under previous GAAP on contracts that commenced prior to adoption of the lease standard. We also elected the land easement practical expedient, which allows us to continue to account for pre-existing land easements under our accounting policy that existed before adoption of the lease standard. We did not elect the practical expedient to use hindsight in making judgments when determining the lease term.  The adoption of Topic 842 affects our balance sheet, as our contracts for office space, service centers and fleet vehicles are operating leases. The following table shows the increases on our balance sheet at January 1, 2019 from the initial adoption of Topic 842.   At January 1, 2019  Operating Leases:  ROU assets:  Operating lease ROU and other assets $ 82   Lease liabilities:  Other current liabilities $ 26  Employee benefit, operating lease and other obligations 56  Total operating lease liabilities $ 82  Topic 220, “Income Statement—Reporting Comprehensive Income” amended by ASU 2018-02, “Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income” – In February 2018, the FASB issued ASU 2018-02, an amendment to Topic 220. Under ASU 2018-02, an entity is required to provide certain disclosures regarding stranded tax effects, including its accounting policy related to releasing the income tax effects from accumulated other comprehensive income (AOCI). We elected to reclassify stranded tax effects resulting from the TCJA from AOCI to capital accounts. Our stranded tax effects in AOCI, which are related to previous interest rate cash flow hedges, were $4 million and increased our capital account upon reclassification. We adopted the standard on a prospective basis effective January 1, 2019.   Topic 350, “Intangibles, Goodwill and Other —Internal-Use Software (Subtopic 40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service ” – In August 2018, the FASB issued ASU 2018-15 which clarifies the accounting for implementation costs in cloud computing arrangements. ASU 2018-15 is required to be adopted in the first quarter of fiscal 2020 with earlier adoption permitted. We have early adopted on a prospective basis effective July 1, 2019. The early adoption is not expected to have a material effect on our consolidated financial statements.

Business and Significant Acco_3

Business and Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2019
Business and Significant Accounting Policies [Abstract]
Schedule Of Adoption Of Topic 842	  At January 1, 2019  Operating Leases:  ROU assets:  Operating lease ROU and other assets $ 82   Lease liabilities:  Other current liabilities $ 26  Employee benefit, operating lease and other obligations 56  Total operating lease liabilities $ 82 

Regulatory Matters (Tables)

Regulatory Matters (Tables)	9 Months Ended
	Sep. 30, 2019
Regulatory Matters [Abstract]
Components Of Regulatory Assets And Liabilities	  Remaining Rate Recovery /Amortization Period  At September 30, 2019 At September 30, 2019 At December 31, 2018  Regulatory assets:  Employee retirement liability (a)(b)(c) To be determined $ 624 $ 648  Employee retirement costs being amortized 8 years 270 297  Employee retirement costs incurred since the last rate review period (b) To be determined 77 73  Self-insurance reserve (primarily storm recovery costs) being amortized 8 years 319 351  Self-insurance reserve incurred since the last rate review period (primarily storm related) (b) To be determined 200 59  Securities reacquisition costs Lives of related debt 30 10  Deferred conventional meter and metering facilities depreciation 1 year 21 36  Under-recovered AMS costs 8 years 169 185  Energy efficiency performance bonus (a) 1 year or less 11 7  Wholesale distribution substation service To be determined 30 15  Other regulatory assets Various 14 10  Total regulatory assets 1,765 1,691   Regulatory liabilities:  Estimated net removal costs Lives of related assets 1,154 1,023  Excess deferred taxes Primarily over lives of related assets 1,592 1,571  Over-recovered wholesale transmission service expense (a) 1 year or less 13 89  Other regulatory liabilities Various 21 14  Total regulatory liabilities 2,780 2,697  Net regulatory assets (liabilities) $ (1,015) $ (1,006) ____________ (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. 

Revenues (Tables)

Revenues (Tables)	9 Months Ended
	Sep. 30, 2019
Revenues [Abstract]
Disaggregation Of Revenues	  Three Months Ended September 30, Nine Months Ended September 30,  2019 2018 2019 2018  Operating revenues  Revenues contributing to earnings:  Distribution base revenues $ 633 $ 604 $ 1,629 $ 1,640  Transmission base revenues (TCOS revenues):  Billed to third-party wholesale customers 181 137 493 403  Billed to REPs serving Oncor distribution customers, through TCRF 105 77 282 234  Total transmission base revenues 286 214 775 637  Other miscellaneous revenues 31 17 66 48  Total revenues contributing to earnings 950 835 2,470 2,325   Revenues collected for pass-through expenses:  TCRF - third-party wholesale transmission service 245 237 759 719  EECRF and other regulatory charges 16 23 39 62  Revenues collected for pass-through expenses 261 260 798 781   Total operating revenues $ 1,211 $ 1,095 $ 3,268 $ 3,106 

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	9 Months Ended
	Sep. 30, 2019
Short-Term Borrowings [Abstract]
Schedule Of Short-Term Borrowings	  At September 30, At December 31,  2019 2018  Total borrowing capacity $ 2,000 $ 2,000  Commercial paper outstanding (a) - (813)  Credit facility outstanding (b) - -  Letters of credit outstanding (c) (10) (9)  Available unused credit $ 1,990 $ 1,178 ____________ a) The weighted average interest rate for commercial paper at December 31, 2018 w as 2.74% . b) At September 30, 2019, the applicable interest rate for any outstanding borrowings would have been LIBOR plus 1.00%. c) The interest rate on outstanding letters of credit at both September 30, 2019 and December 31, 2018 was 1.20% based on our credit ratings.

Long-Term Debt (Tables)

Long-Term Debt (Tables)	9 Months Ended
	Sep. 30, 2019
Long-Term Debt [Abstract]
Schedule Of Long-Term Debt	  September 30, December 31,  2019 2018  Fixed Rate Secured:  2.15% Senior Notes due June 1, 2019 $ - $ 250  5.75% Senior Notes due September 30, 2020 126 126  8.50% Senior Notes, Series C, due December 30, 2020 14 -  4.10% Senior Notes, due June 1, 2022 400 400  7.00% Debentures due September 1, 2022 482 482  2.75% Senior Notes due June 1, 2024 500 -  2.95% Senior Notes due April 1, 2025 350 350  3.86% Senior Notes, Series A, due December 3, 2025 174 -  3.86% Senior Notes, Series B, due January 14, 2026 38 -  3.70% Senior Notes due November 15, 2028 650 350  5.75% Senior Notes due March 15, 2029 318 318  7.25% Senior Notes, Series B, due December 30, 2029 37 -  6.47% Senior Notes, Series A, due September 30, 2030 84 -  7.00% Senior Notes due May 1, 2032 500 500  7.25% Senior Notes due January 15, 2033 350 350  7.50% Senior Notes due September 1, 2038 300 300  5.25% Senior Notes due September 30, 2040 475 475  4.55% Senior Notes due December 1, 2041 400 400  5.30% Senior Notes due June 1, 2042 500 500  3.75% Senior Notes due April 1, 2045 550 550  3.80% Senior Notes due September 30, 2047 325 325  4.10% Senior Notes due November 15, 2048 450 450  3.80% Senior Notes, due June 1, 2049 500 -  3.10% Senior Notes, due September 15, 2049 700 -  Secured long-term debt 8,223 6,126  Unsecured:  Term loan credit agreement maturing December 9, 2019 350 350  Term loan credit agreement maturing October 6, 2020 460 -  Total long-term debt 9,033 6,476  Unamortized discount and debt issuance costs (57) (41)  Less amount due currently (485) (600)  Long-term debt, less amounts due currently $ 8,491 $ 5,835 
Schedule Of Long-Term Debt Maturity	  Year Amount  2019 $ 485  2020 481  2021 9  2022 891  2023 10  Thereafter 7,157  Unamortized discount and debt issuance costs (57)  Total $ 8,976 

Commitments And Contingencies (

Commitments And Contingencies (Tables)	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies [Abstract]
Schedule Of Lease Information	  At September 30,  2019  Operating Leases:  ROU assets:  Operating lease ROU assets and other $ 88   Lease liabilities:  Operating lease and other current liabilities $ 25  Employee benefit, operating lease and other obligations 63  Total operating lease liabilities $ 88   Weighted-average remaining lease term (in years) 4  Weighted-average discount rate 3.4% 
Schedule Of Lease Costs	  Three Months Ended Nine Months Ended  September 30, 2019 September 30, 2019  Operating lease cost:  Operating lease costs (including amounts allocated to property, plant and equipment) $ 10 $ 29  Short-term lease costs 9 32  Total operating lease costs $ 19 $ 61   Operating lease payments:  Cash paid for amounts included in the measurement of lease liabilities $ 8 $ 23  
Schedule Of Operating Lease Maturity	  Year Amount  2019 (remaining three months) $ 8  2020 25  2021 23  2022 17  2023 10  Thereafter 9  Total undiscounted lease payments 92  Less imputed interest (4)  Total future minimum lease payments $ 88 
Schedule Of Future Miinimum Lease Payments Under Operating Leases	  Year Amount  2019 $ 29  2020 22  2021 20  2022 15  2023 8  Thereafter 5  Total future minimum lease payments $ 99 

Membership Interests (Tables)

Membership Interests (Tables)	9 Months Ended
	Sep. 30, 2019
Membership Interests [Abstract]
Schedule Of Cash Capital Contributions	  Payment Date Amount  July 29, 2019 $ 70  May 15, 2019 1,330  April 30, 2019 70  February 19, 2019 70 
Schedule Of Distributions Paid	  Declaration Date Payment Date Amount  July 30, 2019 July 31, 2019 $ 71  May 1, 2019 May 2, 2019 71  February 20, 2019 February 22, 2019 71 
Schedule Of Changes To Membership Interests	  Capital Accounts Accumulated Other Comprehensive Income (Loss) Total Membership Interests  Three Months Ended September 30, 2019  Balance at June 30, 2019 $ 10,210 $ (164) $ 10,046  Net income 263 - 263  Distributions (71) - (71)  Capital contributions 70 - 70  Net effects of cash flow hedges - 1 1  Defined benefit pension plans - 2 2  Balance at September 30, 2019 $ 10,472 $ (161) $ 10,311         Capital Accounts Accumulated Other Comprehensive Income (Loss) Total Membership Interests  Three Months Ended September 30, 2018  Balance at June 30, 2018 $ 8,380 $ (99) $ 8,281  Net income 194 - 194  Distributions (30) - (30)  Net effects of cash flow hedges - 2 2  Balance at September 30, 2018 $ 8,544 $ (97) $ 8,447     Capital Accounts Accumulated Other Comprehensive Income (Loss) Total Membership Interests  Nine Months Ended September 30, 2019  Balance at December 31, 2018 $ 8,624 $ (164) $ 8,460  Net income 518 - 518  Distributions (213) - (213)  Capital contributions 1,540 - 1,540  Net effects of cash flow hedges (Note 1) 3 (1) 2  Defined benefit pension plans - 4 4  Balance at September 30, 2019 $ 10,472 $ (161) $ 10,311     Capital Accounts Accumulated Other Comprehensive Income (Loss) Total Membership Interests  Nine Months Ended September 30, 2018  Balance at December 31, 2017 $ 8,004 $ (101) $ 7,903  Net income 426 - 426  Distributions (30) - (30)  Capital contributions 144 - 144  Net effects of cash flow hedges - 2 2  Defined benefit pension plans - 2 2  Balance at September 30, 2018 $ 8,544 $ (97) $ 8,447  
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, 2018 $ (16) $ (148) $ (164)  Defined benefit pension plans - 5 5  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Amounts reclassified from accumulated other comprehensive income (loss) to capital account (Note 1) (4) - (4)  Balance at September 30, 2019 $ (18) $ (143) $ (161)   Balance at December 31, 2017 $ (18) $ (83) $ (101)  Defined benefit pension plans - 2 2  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at September 30, 2018 $ (16) $ (81) $ (97) 

Pension and OPEB Plans (Tables)

Pension and OPEB Plans (Tables)	9 Months Ended
	Sep. 30, 2019
Pension and OPEB Plans [Abstract]
Schedule Of Pension And OPEB Plan Costs	  Three Months Ended September 30, Nine Months Ended September 30,  2019 2018 2019 2018   Components of net allocated pension costs:  Service cost $ 6 $ 7 $ 19 $ 21  Interest cost 32 29 96 89  Expected return on assets (29) (29) (89) (89)  Amortization of net loss 7 12 22 36  Net pension costs 16 19 48 57  Components of net OPEB costs:  Service cost 2 2 5 6  Interest cost 10 11 32 33  Expected return on assets (2) (2) (6) (6)  Amortization of prior service cost (5) (8) (15) (21)  Amortization of net loss 5 14 14 41  Net OPEB costs 10 17 30 53  Total net pension and OPEB costs 26 36 78 110  Less amounts deferred principally as property or a regulatory asset (7) (17) (20) (52)  Net amounts recognized as operation and maintenance expense or other deductions $ 19 $ 19 $ 58 $ 58 

Related-Party Transactions (Tab

Related-Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2019
Related-Party Transactions [Abstract]
Schedule Of Trade Accounts And Other Receivables From Related Parties	  At September 30, 2019 At December 31, 2018  STH Texas Transmission Total STH Texas Transmission Total   Federal income taxes payable (receivable) $ 10 $ 2 $ 12 $ 4 $ 1 $ 5  Texas margin taxes payable 17 - 17 21 - 21  Net payable (receivable) $ 27 $ 2 $ 29 $ 25 $ 1 $ 26 
Schedule Of Related Party Transactions	  Nine Months Ended September 30, 2019 Nine Months Ended September 30, 2018  STH Texas Transmission Total STH EFH Corp. Texas Transmission Total   Federal income taxes $ 29 $ 7 $ 36 $ 41 $ (19) $ 6 $ 28  Texas margin taxes 22 - 22 21 - - 21  Total payments (receipts) $ 51 $ 7 $ 58 $ 62 $ (19) $ 6 $ 49 

Supplementary Financial Infor_2

Supplementary Financial Information (Tables)	9 Months Ended
	Sep. 30, 2019
Supplementary Financial Information [Abstract]
Schedule Of Other Deductions And (Income)	  Three Months Ended September 30, Nine Months Ended September 30,  2019 2018 2019 2018   Professional fees $ 2 $ - $ 6 $ 4  Sempra Acquisition related costs - - - 16  InfraREIT Acquisition related costs - - 9 -  Recoverable pension and OPEB - non-service costs 14 13 42 40  Non-recoverable pension and OPEB costs (Note 8) 1 1 3 4  Other, including interest income (3) (1) (4) (1)  Total other deductions and (income) - net $ 14 $ 13 $ 56 $ 63 
Schedule Of Interest Expense And Related Charges	  Three Months Ended September 30, Nine Months Ended September 30,  2019 2018 2019 2018   Interest $ 98 $ 90 $ 280 $ 268  Amortization of debt issuance costs and discounts 3 2 7 5  Less allowance for funds used during construction – capitalized interest portion (4) (3) (11) (9)  Total interest expense and related charges $ 97 $ 89 $ 276 $ 264 
Schedule Of Trade Accounts And Other Receivables	  At September 30, At December 31,  2019 2018   Gross trade accounts and other receivables $ 788 $ 562  Allowance for uncollectible accounts (4) (3)  Trade accounts receivable – net $ 784 $ 559 
Summary of Investments And Other Property	  At September 30, At December 31,  2019 2018   Assets related to employee benefit plans, including employee savings programs $ 113 $ 108  Land 12 12  Other 2 -  Total investments and other property $ 127 $ 120 
Schedule Of Property, Plant And Equipment	  Composite Depreciation Rate/ At September 30, At December 31,  Avg. Life at September 30, 2019 2019 2018  Assets in service:  Distribution 2.8% / 35.7 years $ 13,833 $ 13,105  Transmission 2.8% / 35.1 years 10,681 8,568  Other assets 6.9% / 14.5 years 1,546 1,497  Total 26,060 23,170  Less accumulated depreciation 7,949 7,513  Net of accumulated depreciation 18,111 15,657  Construction work in progress 843 417  Held for future use 19 16  Property, plant and equipment – net $ 18,973 $ 16,090 
Schedule Of Intangible Assets	  At September 30, 2019 At December 31, 2018  Gross Gross  Carrying Accumulated Carrying Accumulated  Amount Amortization Net Amount Amortization Net   Identifiable intangible assets subject to amortization:  Land easements $ 559 $ 106 $ 453 $ 464 $ 101 $ 363  Capitalized software 806 422 384 787 385 402  Total $ 1,365 $ 528 $ 837 $ 1,251 $ 486 $ 765 
Schedule Of Estimated Aggregate Amortization Expenses	  Year Amortization Expense  2019 $ 52  2020 52  2021 52  2022 52  2023 51 
Schedule Of Employee Benefit Obligations And Other	  At September 30, At December 31,  2019 2018   Retirement plans and other employee benefits 1,854 $ 1,858  Operating lease liabilities 62 -  Investment tax credits 7 8  Other 82 77  Total employee benefit, operating lease and other obligations $ 2,005 $ 1,943 
Schedule Of Supplemental Cash Flow Information	  Nine Months Ended September 30,  2019 2018   Cash payments (receipts) related to:  Interest $ 256 $ 243  Less capitalized interest (11) (9)  Interest payments (net of amounts capitalized) $ 245 $ 234  Amount in lieu of income taxes (a):  Federal $ 36 $ 28  State 22 21  Total payments (receipts) in lieu of income taxes $ 58 $ 49   Noncash increase in operating lease obligations for ROU assets $ 26 $ -   Noncash investing and financing activity (b):  Acquisition:  Assets acquired 2,545 $ -  Liabilities assumed (1,221) -  Cash paid $ 1,324 $ -   Noncash construction expenditures (c) $ 257 $ 136 ____________ (a) See Note 9 for income tax related detail. (b) See Note 5 for more information on noncash debt exchanges related to InfraREIT Acquisition. (c) Represents end-of-period accruals .

Infrareit Acqusition (Tables)

Infrareit Acqusition (Tables)	9 Months Ended
	Sep. 30, 2019
Infrareit Acquisition [Abstract]
Total Purchase Price Paid	  The total purchase price paid was comprised of the following   Purchase of outstanding InfraREIT shares and units $ 1,275  Certain transaction costs of InfraREIT paid by Oncor (a) 49  Total purchase price paid $ 1,324 __________________ (a) Represents certain transaction costs incurred by InfraREIT in connection with the transaction and paid by Oncor, including a $40 million management termination fee payable to an affiliate of Hunt Consolidated, Inc.
Assets And Liabilities Assumed	  Purchase price allocation is as follows:  As of May 16, 2019  Assets acquired:  Current assets $ 44  Property, plant and equipment - net 1,800  Goodwill 675  Regulatory assets 16  Other noncurrent assets 10  Total assets acquired 2,545   Liabilities assumed:  Short-term debt 114  Other current liabilities 22  Regulatory liabilities 148  Liability in lieu of deferred income taxes 98  Long-term debt, including due currently 839  Total liabilities assumed 1,221  Net assets acquired 1,324  Total purchase price paid $ 1,324 
Pro Forma Information	  Nine Months Ended September 30,  2019 2018  Oncor Consolidated Pro Forma Revenues $ 3,352 $ 3,268 

Business and Significant Acco_4

Business and Significant Accounting Policies (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2019USD ($)segment	Jan. 01, 2019USD ($)	Dec. 31, 2018USD ($)
Business And Significant Accounting Polices [Line Items]
Number of reportable business segments | segment	0
Goodwill	$ 4,739		$ 4,064
Operating lease obligations	88
Accounting Standards Update 2016-02 [Member]
Business And Significant Accounting Polices [Line Items]
Operating lease obligations		$ 82
Accounting Standards Update 2018-02 [Member]
Business And Significant Accounting Polices [Line Items]
Reclassification from AOCI to membership interests for stranded tax effects	$ 4
Oncor Holdings [Member]
Business And Significant Accounting Polices [Line Items]
Ownership	80.25%
Texas Transmission [Member]
Business And Significant Accounting Polices [Line Items]
Percentage of membership interest owned by non-controlling owners	19.75%

Business and Significant Acco_5

Business and Significant Accounting Policies (Schedule Of Adoption Of Topic 842) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease ROU assets and other	$ 88
Other current liabilities	25
Employee benefit, operating lease and other obligations	63
Total operating lease liabilities	$ 88
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease ROU assets and other		$ 82
Other current liabilities		26
Employee benefit, operating lease and other obligations		56
Total operating lease liabilities		$ 82

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details) - USD ($) $ in Millions	Jul. 09, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Nov. 26, 2017	Dec. 31, 2017	May 30, 2019	Dec. 31, 2018
Regulatory Matters [Abstract]
U.S. federal statutory rate				21.00%		35.00%
DCRF increase							$ 25
Reconciliation of all costs incurred with revenues					$ 87
Net operating cost savings	$ 16
Authorized under-recovery reconciliation costs	$ 6
Decrease in revenue requirement								$ 181
Annual rate reductions related to reduction in income taxes			$ 144
Reduction related to amortization of excess deferred income taxes			$ 75
Increase in regulatory liabililty		$ 9

Regulatory Matters (Components

Regulatory Matters (Components Of Regulatory Assets And Liabilities) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Regulatory Assets And Liabilities [Line Items]
Carrying Amount, Regulatory Assets	$ 1,765	$ 1,691
Carrying Amount, Regulatory Liabilities	2,780	2,697
Net regulatory assets (liabilities)	$ (1,015)	(1,006)
Estimated Net Removal Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	Lives of related assets
Carrying Amount, Regulatory Liabilities	$ 1,154	1,023
Excess Deferred Taxes [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	Primarily over lives of related assets
Carrying Amount, Regulatory Liabilities	$ 1,592	1,571
Over-Recovered Wholesale Transmission Service Expense [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	1 year or less
Carrying Amount, Regulatory Liabilities	$ 13	89
Other Regulatory Liabilities [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	Various
Carrying Amount, Regulatory Liabilities	$ 21	14
Employee Retirement Liability [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	To be determined
Carrying Amount, Regulatory Assets	$ 624	648
Employee Retirement Costs Being Amortized [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	8 years
Carrying Amount, Regulatory Assets	$ 270	297
Employee Retirement Costs Incurred Since The Last Rate Review Period [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	To be determined
Carrying Amount, Regulatory Assets	$ 77	73
Self-Insurance Reserve (Primarily Storm Recovery Costs) Being Amortized [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	8 years
Carrying Amount, Regulatory Assets	$ 319	351
Self-Insurance Reserve Incurred Since The Last Rate Review Period (Primarily Storm Related) [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	To be determined
Carrying Amount, Regulatory Assets	$ 200	59
Securities Reacquisition Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	Lives of related debt
Carrying Amount, Regulatory Assets	$ 30	10
Deferred Conventional Meter And Metering Facilities Depreciation [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	1 year
Carrying Amount, Regulatory Assets	$ 21	36
Under-recovered AMS Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	8 years
Carrying Amount, Regulatory Assets	$ 169	185
Energy Efficiency Performance Bonus [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	1 year or less
Carrying Amount, Regulatory Assets	$ 11	7
Wholesale Distribution Substation Service [Member]
Regulatory Assets And Liabilities [Line Items]
Carrying Amount, Regulatory Assets	$ 30	15
Remaining Rate Recovery/Amortization Period	To be determined
Other Regulatory Assets [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	Various
Carrying Amount, Regulatory Assets	$ 14	$ 10

Revenues (Narrative) (Details)

Revenues (Narrative) (Details) - item	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Number of REPS		90
REP Subsidiary One [Member] | Revenue Benchmark [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	24.00%	22.00%
REP Subsidiary Two [Member] | Revenue Benchmark [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	19.00%	18.00%

Revenues (Disaggregation Of Rev

Revenues (Disaggregation Of Revenues) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	$ 950	$ 835	$ 2,470	$ 2,325
Revenues collected for pass-through expenses	261	260	798	781
Total operating revenues	1,211	1,095	3,268	3,106
Distribution Base Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	633	604	1,629	1,640
Transmission Base Revenues (TCOS Revenues) [Member]
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	286	214	775	637
Transmission Base Revenues (TCOS Revenues) [Member] | Third-Party Wholesale Customers [Member]
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	181	137	493	403
Transmission Base Revenues (TCOS Revenues) [Member] | REPS Serving Oncor Distribution Customers, Through TCRF [Member]
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	105	77	282	234
Other Miscellaneous Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	31	17	66	48
TCRF - Third-party Wholesale Transmission Service [Member]
Disaggregation of Revenue [Line Items]
Revenues collected for pass-through expenses	245	237	759	719
EECRF And Other Regulatory Charges [Member]
Disaggregation of Revenue [Line Items]
Revenues collected for pass-through expenses	$ 16	$ 23	$ 39	$ 62

Short-Term Borrowings (Narrativ

Short-Term Borrowings (Narrative) (Details) $ in Millions	May 15, 2019USD ($)	May 09, 2019	Sep. 30, 2019USD ($)contract	Dec. 31, 2018USD ($)
Line of Credit Facility [Line Items]
Short-term Debt				$ 813
Payment of acquired entity credit facilities			$ (114)
Borrowing capacity available under the credit facility			2,000	2,000
Bridge Loan [Member]
Line of Credit Facility [Line Items]
Short-term Debt	$ 600
Short-term Debt, Terms		P6M
Interest rate per annum		0.075%
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Outstanding borrowing under the revolving credit facility			10	9
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 2,000
Number of revolving credit facilities extension options | contract			2
Extension period for revolving line of credit			1 year
Credit facility, term			5 years
Expiration of revolving credit facility			Nov. 1, 2022
Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Additional increase in borrowing capacity amount			$ 400
Revolving Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Additional increase in borrowing capacity amount			100
Commercial Paper [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 2,000
Outstanding borrowing under the revolving credit facility				$ 813
London Interbank Offered Rate (LIBOR) [Member] | Bridge Loan [Member]
Line of Credit Facility [Line Items]
Spread over variable rate	0.65%
One-Month London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Spread over variable rate			1.00%

Short-Term Borrowings (Schedule

Short-Term Borrowings (Schedule Of Short-Term Borrowings) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Short-term Debt [Line Items]
Total borrowing capacity	$ 2,000	$ 2,000
Available unused credit	1,990	1,178
Commercial Paper [Member]
Short-term Debt [Line Items]
Outstanding		$ (813)
Interest Rate		2.74%
Letter of Credit [Member]
Short-term Debt [Line Items]
Outstanding	$ (10)	$ (9)
Interest Rate	1.20%	1.20%
One-Month London Interbank Offered Rate [Member]
Short-term Debt [Line Items]
Spread over variable rate	1.00%

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($)	May 17, 2019	May 16, 2019	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Long-Term Debt [Line Items]
Repayments of long-term debt			$ 742,000,000	$ 825,000,000
Proceeds from sale of Notes			0
Estimated fair value of our long-term debt including current maturities			10,477,000,000,000		$ 7,086,000,000,000
Carrying amount			8,976,000,000,000		6,435,000,000,000
InfraREIT [Member]
Long-Term Debt [Line Items]
Repayments of long-term debt			$ 488,000,000
One-Month London Interbank Offered Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate			1.00%
2.15% Fixed Senior Notes Due June 1, 2019 [Member]
Long-Term Debt [Line Items]
Repayments of long-term debt			$ 250,000,000
4.10% Fixed Senior Notes Due November 15, 2048 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			450,000,000		450,000,000
6.47% Senior Notes, Series A, due September 30, 2030 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			84,000,000
7.25% Senior Notes, Series B, due December 30, 2029 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			37,000,000
8.50% Senior Notes, Series C, due December 30, 2020 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			14,000,000
3.86% Senior Notes, Series A, due December 3, 2025 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			174,000,000
3.86% Senior Notes, Series B, due January 14, 2026 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			38,000,000
3.10% Senior Notes, due September 15, 2049 [Member]
Long-Term Debt [Line Items]
Proceeds from sale of Notes			689,000,000
2.75% Senior Notes due June 1, 2024 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			$ 500,000,000
Term Loan Credit Agreement Maturing October 6, 2020 [Member] | London Interbank Offered Rate (LIBOR) [Member]
Long-Term Debt [Line Items]
Spread over variable rate			0.50%
Term Loan Credit Agreement Maturing October 6, 2020 [Member] | Federal Funds Effective Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate			0.50%
Term Loan Credit Agreement Maturing October 6, 2020 [Member] | One-Month London Interbank Offered Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate			1.00%
Note Purchase Agreements [Member]
Long-Term Debt [Line Items]
Accrued interest			$ 6,000,000
New Indenture Notes [Member]
Long-Term Debt [Line Items]
Increase in basis points per annum			0.50%
Secured Debt [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			$ 8,223,000,000		6,126,000,000
Percentage of fair value of cost of property additions certified to the Deed of Trust collateral agent			85.00%
Available bond credits			$ 2,784,000,000,000
Future debt subject to property additions to the Deed of Trust			1,942,000,000,000
Secured Debt [Member] | 2.15% Fixed Senior Notes Due June 1, 2019 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount					250,000,000
Secured Debt [Member] | 3.70% Fixed Senior Notes Due November 15, 2028 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			650,000,000		350,000,000
Secured Debt [Member] | 5.75% Fixed Senior Notes Due March 15, 2029 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			318,000,000		318,000,000
Secured Debt [Member] | 7.00% Fixed Debentures Due September 1, 2022 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			482,000,000		482,000,000
Secured Debt [Member] | 3.10% Senior Notes, due September 15, 2049 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			700,000,000
Secured Debt [Member] | 3.80% Senior Notes, due June 1, 2049 [Member]
Long-Term Debt [Line Items]
Aggregate principal amount			500,000,000
Unsecured Debt [Member] | Term Loan Credit Agreement Maturing December 9, 2019 [Member]
Long-Term Debt [Line Items]
Term loan			350,000,000		$ 350,000,000
Unsecured Debt [Member] | Term Loan Credit Agreement Maturing October 6, 2020 [Member]
Long-Term Debt [Line Items]
Term loan			$ 460,000,000
InfraREIT [Member]
Long-Term Debt [Line Items]
Repayments of long-term debt	$ 602,000,000	$ 288,000,000
Extinguishment of Debt, Amount		839,000,000
Accrued interest		5,000,000
Make-whole fees		19,000,000
InfraREIT [Member] | Subsidiary Term Loan [Member]
Long-Term Debt [Line Items]
Repayments of long-term debt		200,000,000
Debt principal amount		$ 351,000,000

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, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total long-term debt	$ 9,033	$ 6,476
Unamortized discount and debt issuance costs	(57)	(41)
Less amount due currently	(485)	(600)
Long-term debt, less amounts due currently	8,491	5,835
Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 8,223	6,126
2.15% Fixed Senior Notes Due June 1, 2019 [Member]
Debt Instrument [Line Items]
Interest percentage	2.15%
2.15% Fixed Senior Notes Due June 1, 2019 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt		$ 250
5.75% Fixed Senior Notes Due September 30, 2020 [Member]
Debt Instrument [Line Items]
Interest percentage	5.75%	5.75%
Due date	Sep. 30, 2020	Sep. 30, 2020
5.75% Fixed Senior Notes Due September 30, 2020 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 126	$ 126
8.50% Senior Notes, Series C, due December 30, 2020 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 14
Interest percentage	8.50%	8.50%
Due date	Dec. 30, 2020	Dec. 30, 2020
4.10% Fixed Senior Notes Due June 1, 2022 [Member]
Debt Instrument [Line Items]
Interest percentage	4.10%	4.10%
4.10% Fixed Senior Notes Due June 1, 2022 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 400	$ 400
7.00% Fixed Debentures Due September 1, 2022 [Member]
Debt Instrument [Line Items]
Interest percentage	7.00%	7.00%
7.00% Fixed Debentures Due September 1, 2022 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 482	$ 482
2.75% Senior Notes due June 1, 2024 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 500
Interest percentage	2.75%	2.75%
Due date	Jun. 1, 2024	Jun. 1, 2024
2.95% Fixed Senior Notes Due April 1, 2025 [Member]
Debt Instrument [Line Items]
Interest percentage	2.95%	2.95%
2.95% Fixed Senior Notes Due April 1, 2025 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 350	$ 350
3.86% Senior Notes, Series A, due December 3, 2025 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 174
Interest percentage	3.86%	3.86%
Due date	Dec. 3, 2025	Dec. 3, 2025
3.86% Senior Notes, Series B, due January 14, 2026 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 38
Interest percentage	3.86%	3.86%
Due date	Jan. 14, 2026	Jan. 14, 2026
3.70% Fixed Senior Notes Due November 15, 2028 [Member]
Debt Instrument [Line Items]
Interest percentage	3.70%	3.70%
3.70% Fixed Senior Notes Due November 15, 2028 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 650	$ 350
5.75% Fixed Senior Notes Due March 15, 2029 [Member]
Debt Instrument [Line Items]
Interest percentage	5.75%	5.75%
Due date	Mar. 15, 2029	Mar. 15, 2029
5.75% Fixed Senior Notes Due March 15, 2029 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 318	$ 318
7.25% Senior Notes, Series B, due December 30, 2029 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 37
Interest percentage	7.25%	7.25%
Due date	Dec. 30, 2029	Dec. 30, 2029
6.47% Senior Notes, Series A, due September 30, 2030 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 84
Interest percentage	6.47%	6.47%
Due date	Sep. 30, 2030	Sep. 30, 2030
7.00% Fixed Senior Notes Due May 1, 2032 [Member]
Debt Instrument [Line Items]
Interest percentage	7.00%	7.00%
7.00% Fixed Senior Notes Due May 1, 2032 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 500	$ 500
7.25% Fixed Senior Notes Due January 15, 2033 [Member]
Debt Instrument [Line Items]
Interest percentage	7.25%	7.25%
7.25% Fixed Senior Notes Due January 15, 2033 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 350	$ 350
7.50% Fixed Senior Notes Due September 1, 2038 [Member]
Debt Instrument [Line Items]
Interest percentage	7.50%	7.50%
7.50% Fixed Senior Notes Due September 1, 2038 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 300	$ 300
5.25% Fixed Senior Notes Due September 30, 2040 [Member]
Debt Instrument [Line Items]
Interest percentage	5.25%	5.25%
5.25% Fixed Senior Notes Due September 30, 2040 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 475	$ 475
4.55% Fixed Senior Notes Due December 1, 2041 [Member]
Debt Instrument [Line Items]
Interest percentage	4.55%	4.55%
4.55% Fixed Senior Notes Due December 1, 2041 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 400	$ 400
5.30% Fixed Senior Notes Due June 1, 2042 [Member]
Debt Instrument [Line Items]
Interest percentage	5.30%	5.30%
5.30% Fixed Senior Notes Due June 1, 2042 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 500	$ 500
3.75% Fixed Senior Notes Due April 1, 2045 [Member]
Debt Instrument [Line Items]
Interest percentage	3.75%	3.75%
Due date	Apr. 1, 2045	Apr. 1, 2045
3.75% Fixed Senior Notes Due April 1, 2045 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 550	$ 550
3.80% Fixed Senior Notes Due September 30, 2047 [Member]
Debt Instrument [Line Items]
Interest percentage	3.80%	3.80%
Due date	Sep. 30, 2047	Sep. 30, 2047
3.80% Fixed Senior Notes Due September 30, 2047 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 325	$ 325
4.10% Fixed Senior Notes Due November 15, 2048 [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 450	$ 450
Interest percentage	4.10%	4.10%
Due date	Nov. 15, 2048	Nov. 15, 2048
3.80% Senior Notes, due June 1, 2049 [Member]
Debt Instrument [Line Items]
Interest percentage	3.80%	3.80%
Due date	Jun. 1, 2049	Jun. 1, 2049
3.80% Senior Notes, due June 1, 2049 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 500
3.10% Senior Notes, due September 15, 2049 [Member]
Debt Instrument [Line Items]
Interest percentage	3.10%	3.10%
Due date	Sep. 15, 2049	Sep. 15, 2049
3.10% Senior Notes, due September 15, 2049 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 700
Term Loan Credit Agreement Maturing December 9, 2019 [Member]
Debt Instrument [Line Items]
Due date	Dec. 9, 2019	Dec. 9, 2019
Term Loan Credit Agreement Maturing December 9, 2019 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Term loan	$ 350	$ 350
Term Loan Credit Agreement Maturing October 6, 2020 [Member]
Debt Instrument [Line Items]
Due date	Oct. 6, 2020	Oct. 6, 2020
Term Loan Credit Agreement Maturing October 6, 2020 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Term loan	$ 460

Long-Term Debt (Schedule Of L_2

Long-Term Debt (Schedule Of Long-Term Debt Maturity) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Long-Term Debt [Abstract]
2019	$ 485
2020	481
2021	9
2022	891
2023	10
Thereafter	7,157
Unamortized discount and debt issuance costs	(57)	$ (41)
Total	$ 8,976

Commitments And Contingencies_2

Commitments And Contingencies (Schedule Of Lease Information) (Details) $ in Millions	Sep. 30, 2019USD ($)
Commitments and Contingencies [Abstract]
Operating lease ROU and other assets	$ 88
Operating and other current liabilities	25
Employee benefit, operating lease and other obligations	63
Total operating lease liabilities	$ 88
Weighted-average remaining lease term (in years)	4 years
Weighted-average discount rate	3.40%

Commitments And Contingencies_3

Commitments And Contingencies (Schedule Of Lease Costs) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Commitments and Contingencies [Abstract]
Operating lease costs (including amounts allocated to property, plant and equipment)	$ 10	$ 29
Short-term lease costs	9	32
Total operating lease costs	19	61
Cash paid for amounts included in the measurement of lease liabilities	$ 8	$ 23

Commitments And Contingencies_4

Commitments And Contingencies (Schedule Of Operating Lease Maturity) (Details) $ in Millions	Sep. 30, 2019USD ($)
Commitments and Contingencies [Abstract]
2019 (remaining three months)	$ 8
2020	25
2021	23
2022	17
2023	10
Thereafter	9
Total undiscounted lease payments	92
Less imputed interest	(4)
Total future minimum lease payments	$ 88

Commitments And Contingencies_5

Commitments And Contingencies (Schedule Of Future Minimum Lease Payments Under Operating Leases) (Details) $ in Millions	Sep. 30, 2019USD ($)
Commitments and Contingencies [Abstract]
2019	$ 29
2020	22
2021	20
2022	15
2023	8
Thereafter	5
Total future minimum lease payments	$ 99

Membership Interests (Narrative

Membership Interests (Narrative) (Details) - USD ($) $ in Millions	Oct. 31, 2019	Oct. 28, 2019	Jul. 29, 2019	May 15, 2019	Apr. 30, 2019	Feb. 19, 2019	Sep. 30, 2019	Sep. 30, 2018
Subsequent Event [Line Items]
Cash restricted for distribution under the capital structure restriction							$ 27
Regulatory capitalization ratio, debt							57.50%
Regulatory capitalization ratio, equity							42.50%
Current regulatory capitalization ratio, debt							57.40%
Current regulatory capitalization ratio, equity							42.60%
Members contribution			$ 70	$ 1,330	$ 70	$ 70	$ 1,540	$ 144
Subsequent Event [Member]
Subsequent Event [Line Items]
Members contribution		$ 98
Contingent equity distribution	$ 106
Sempra Texas Holdings [Member]
Subsequent Event [Line Items]
Members contribution				$ 1,330

Membership Interests (Schedule

Membership Interests (Schedule Of Cash Capital Contributions) (Details) - USD ($) $ in Millions	Jul. 29, 2019	May 15, 2019	Apr. 30, 2019	Feb. 19, 2019	Sep. 30, 2019	Sep. 30, 2018
Membership Interests [Abstract]
Members contribution	$ 70	$ 1,330	$ 70	$ 70	$ 1,540	$ 144

Membership Interests (Schedul_2

Membership Interests (Schedule Of Distributions Paid) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Dividends Payable [Line Items]
Amount	$ 213	$ 30
Payment One FY 2019 [Member]
Dividends Payable [Line Items]
Declaration Date	Feb. 20, 2019
Payment Date	Feb. 22, 2019
Amount	$ 71
Payment Two FY 2019 [Member]
Dividends Payable [Line Items]
Declaration Date	May 1, 2019
Payment Date	May 2, 2019
Amount	$ 71
Payment Three FY 2019 [Member]
Dividends Payable [Line Items]
Declaration Date	Jul. 30, 2019
Payment Date	Jul. 31, 2019
Amount	$ 71

Membership Interests (Schedul_3

Membership Interests (Schedule Of Changes To Membership Interests) (Details) - USD ($) $ in Millions	Jul. 29, 2019	May 15, 2019	Apr. 30, 2019	Feb. 19, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Balance							$ 8,460
Net income					$ 263	$ 194	518	$ 426
Distributions							(213)	(30)
Capital contributions	$ 70	$ 1,330	$ 70	$ 70			1,540	144
Net effects of cash flow hedges							(2)	2
Defined benefit pension plans					1	1	4	2
Balance					10,311		10,311
Capital Accounts [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Balance					10,210	8,380	8,624	8,004
Net income					263	194	518	426
Distributions					(71)	(30)	(213)	(30)
Capital contributions					70		1,540	144
Net effects of cash flow hedges							3
Defined benefit pension plans
Balance					10,472	8,544	10,472	8,544
Accumulated Other Comprehensive Income (Loss) [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Balance					(164)	(99)	(164)	(101)
Net income
Distributions
Capital contributions
Net effects of cash flow hedges					1	2	(1)	2
Defined benefit pension plans					2		4	2
Balance					(161)	(97)	(161)	(97)
Membership Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Balance					10,046	8,281	8,460	7,903
Net income					263	194	518	426
Distributions					(71)	(30)	(213)	(30)
Capital contributions					70		1,540	144
Net effects of cash flow hedges					1	2	2	2
Defined benefit pension plans					2		4	2
Balance					$ 10,311	$ 8,447	$ 10,311	$ 8,447

Membership Interests (Schedul_4

Membership Interests (Schedule Of Changes To Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (164)
Balance at end of period	(161)
Cash Flow Hedges - Interest Rate Swap [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(16)	$ (18)
Defined benefit pension plans
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges	2	2
Amounts reclassified from accumulated other comprehensive income (loss) to the capital account (Note 1)	(4)
Balance at end of period	(18)	(16)
Defined Benefit Pension and OPEB Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(148)	(83)
Defined benefit pension plans	5	2
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges
Amounts reclassified from accumulated other comprehensive income (loss) to the capital account (Note 1)
Balance at end of period	(143)	(81)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(164)	(101)
Defined benefit pension plans	5	2
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges	2	2
Amounts reclassified from accumulated other comprehensive income (loss) to the capital account (Note 1)	(4)
Balance at end of period	$ (161)	$ (97)

Pension and OPEB Plans (Narrati

Pension and OPEB Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets	$ 1,765		$ 1,765		$ 1,691
Oncor Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate			4.16%
Expected return on plan assets			5.43%
Vistra Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate			4.40%
Expected return on plan assets			5.29%
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected return on assets	29	$ 29	$ 89	$ 89
Amortization of net loss	(7)	(12)	(22)	(36)
Cash contributions			26
Additional cash contributions	15		15
Additional cash contributions, next five years			527
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected return on assets	2	2	6	6
Amortization of net loss	(5)	(14)	(14)	(41)
Amortization of prior service cost	(5)	$ (8)	$ (15)	$ (21)
Discount rate			4.41%
Expected return on plan assets			6.19%
Cash contributions			$ 26
Additional cash contributions	$ 9		9
Additional cash contributions, next five years			$ 175

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Net costs	$ 26	$ 36	$ 78	$ 110
Less amounts deferred principally as property or a regulatory asset	(7)	(17)	(20)	(52)
Net amounts recognized as expense	19	19	58	58
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	6	7	19	21
Interest cost	32	29	96	89
Expected return on assets	(29)	(29)	(89)	(89)
Amortization of net loss	7	12	22	36
Net costs	16	19	48	57
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2	2	5	6
Interest cost	10	11	32	33
Expected return on assets	(2)	(2)	(6)	(6)
Amortization of prior service cost	(5)	(8)	(15)	(21)
Amortization of net loss	5	14	14	41
Net costs	$ 10	$ 17	$ 30	$ 53

Related-Party Transactions (Nar

Related-Party Transactions (Narrative) (Details) - USD ($) $ in Millions	Oct. 28, 2019	Jul. 29, 2019	May 15, 2019	Apr. 30, 2019	Feb. 19, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Related Party Transaction [Line Items]
Revenue						$ 1,211	$ 1,095		$ 3,268	$ 3,106
Members contribution		$ 70	$ 1,330	$ 70	$ 70				1,540	144
Wholesale transmission service						$ 245	$ 237		$ 759	$ 719
Subsequent Event [Member]
Related Party Transaction [Line Items]
Members contribution	$ 98
Sempra Texas Holdings [Member]
Related Party Transaction [Line Items]
Members contribution			$ 1,330
InfraREIT [Member]
Related Party Transaction [Line Items]
Revenue								$ 5
Cash payments to vendors								$ 1

Related-Party Transactions (Sch

Related-Party Transactions (Schedule Of Trade Accounts And Other Receivables From Related Parties) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Texas margin taxes payable	$ 29	$ 26
Net payable (receivable)	29	26
Texas [Member]
Related Party Transaction [Line Items]
Texas margin taxes payable	17	21
Federal [Member]
Related Party Transaction [Line Items]
Federal income taxes payable (receivable)	12	5
Sempra Texas Holdings [Member]
Related Party Transaction [Line Items]
Net payable (receivable)	27
Sempra Texas Holdings [Member] | Texas [Member]
Related Party Transaction [Line Items]
Texas margin taxes payable	17
Sempra Texas Holdings [Member] | Federal [Member]
Related Party Transaction [Line Items]
Federal income taxes payable (receivable)	10
EFH Corp [Member]
Related Party Transaction [Line Items]
Net payable (receivable)		25
EFH Corp [Member] | Texas [Member]
Related Party Transaction [Line Items]
Texas margin taxes payable		21
EFH Corp [Member] | Federal [Member]
Related Party Transaction [Line Items]
Federal income taxes payable (receivable)		4
Texas Transmission Investment LLC [Member]
Related Party Transaction [Line Items]
Net payable (receivable)	2	1
Texas Transmission Investment LLC [Member] | Federal [Member]
Related Party Transaction [Line Items]
Federal income taxes payable (receivable)	$ 2	$ 1

Related-Party Transactions (S_2

Related-Party Transactions (Schedule Of Related Party Transactions) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Related Party Transaction [Line Items]
Federal income taxes	$ 36	$ 28
Texas margin taxes	22	21
Total payments (receipts)	58	49
Sempra Texas Holdings [Member]
Related Party Transaction [Line Items]
Federal income taxes	29	41
Texas margin taxes	22	21
Total payments (receipts)	51	62
EFH Corp [Member]
Related Party Transaction [Line Items]
Federal income taxes		(19)
Total payments (receipts)		(19)
Texas Transmission Investment LLC [Member]
Related Party Transaction [Line Items]
Federal income taxes	7	6
Total payments (receipts)	$ 7	$ 6

Supplementary Financial Infor_3

Supplementary Financial Information (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Dec. 31, 2018
Supplemental Financial Information [Line Items]
Increase in property, plant and equipment		$ 1,800
Aggregate amortization expenses	$ 13	39
Goodwill	$ 4,739	$ 4,739	$ 4,064
Trade Accounts Receivable [Member] | Nonaffiliated REP [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage		16.00%	13.00%
Trade Accounts Receivable [Member] | Second Nonaffiliated REP [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage		14.00%	10.00%

Supplementary Financial Infor_4

Supplementary Financial Information (Schedule Of Other Deductions And (Income)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Supplementary Financial Information [Abstract]
Professional fees	$ 2		$ 6	$ 4
Sempra Acquisition related costs				16
InfraREIT Acquisition related costs			9
Recoverable pension and OPEB - non-service costs	14	$ 13	42	40
Non-recoverable pension and OPEB (Note 8)	1	1	3	4
Other, including interest income	(3)	(1)	(4)	(1)
Total other deductions and (income) - net	$ 14	$ 13	$ 56	$ 63

Supplementary Financial Infor_5

Supplementary Financial Information (Schedule Of Interest Expense And Related Charges) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Supplementary Financial Information [Abstract]
Interest	$ 98	$ 90	$ 280	$ 268
Amortization of debt issuance costs and discounts	3	2	7	5
Less allowance for funds used during construction — capitalized interest portion	(4)	(3)	(11)	(9)
Total interest expense and related charges	$ 97	$ 89	$ 276	$ 264

Supplementary Financial Infor_6

Supplementary Financial Information (Schedule Of Trade Accounts And Other Receivables) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Supplementary Financial Information [Abstract]
Gross trade accounts and other receivables	$ 788	$ 562
Allowance for uncollectible accounts	(4)	(3)
Trade accounts receivable - net	$ 784	$ 559

Supplementary Financial Infor_7

Supplementary Financial Information (Summary of Investments And Other Property) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Supplementary Financial Information [Abstract]
Assets related to employee benefit plans, including employee savings programs	$ 113	$ 108
Land	12	12
Other	2
Total investments and other property	$ 127	$ 120

Supplementary Financial Infor_8

Supplementary Financial Information (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Property Plant and Equipment [Line Items]
Total assets in service	$ 26,060	$ 23,170
Less accumulated depreciation and amortization	7,949	7,513
Net of accumulated depreciation and amortization	18,111	15,657
Construction work in progress	843	417
Held for future use	19	16
Property, plant and equipment - net	18,973	16,090
Distribution [Member]
Property Plant and Equipment [Line Items]
Total assets in service	$ 13,833	13,105
Composite depreciation rate	2.80%
Avg. life	35 years 8 months 12 days
Transmission [Member]
Property Plant and Equipment [Line Items]
Total assets in service	$ 10,681	8,568
Composite depreciation rate	2.80%
Avg. life	35 years 1 month 6 days
Other Assets [Member]
Property Plant and Equipment [Line Items]
Total assets in service	$ 1,546	$ 1,497
Composite depreciation rate	6.90%
Avg. life	14 years 6 months

Supplementary Financial Infor_9

Supplementary Financial Information (Schedule Of Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,365	$ 1,251
Accumulated Amortization	528	486
Net	837	765
Land Easements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	559	464
Accumulated Amortization	106	101
Net	453	363
Capitalized Software [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	806	787
Accumulated Amortization	422	385
Net	$ 384	$ 402

Supplementary Financial Info_10

Supplementary Financial Information (Schedule Of Estimated Aggregate Amortization Expenses) (Details) $ in Millions	Sep. 30, 2019USD ($)
Supplementary Financial Information [Abstract]
2019	$ 52
2020	52
2021	52
2022	52
2023	$ 51

Supplementary Financial Info_11

Supplementary Financial Information (Schedule Of Employee Benefit Obligations And Other) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Supplementary Financial Information [Abstract]
Retirement plans and other employee benefits	$ 1,854	$ 1,858
Operating lease liabilities	62
Investment tax credits	7	8
Other	82	77
Total employee benefit obligations and other	$ 2,005	$ 1,943

Supplementary Financial Info_12

Supplementary Financial Information (Schedule Of Supplemental Cash Flow Information) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Supplementary Financial Information [Abstract]
Interest	$ 256	$ 243
Less capitalized interest	(11)	(9)
Interest payments (net of amounts capitalized)	245	234
Federal	36	28
State	22	21
Total payments (receipts) in lieu of income taxes	58	49
Noncash increase in operating lease obligations for ROU assets	26
Assets acquired	2,545
Liabilities assumed	(1,221)
Cash paid	1,324
Noncash construction expenditures	$ 257	$ 136

Infrareit Acquisition (Narrativ

Infrareit Acquisition (Narrative) (Details) $ / shares in Units, $ in Millions	Oct. 28, 2019USD ($)	Jul. 29, 2019USD ($)	May 17, 2019USD ($)	May 16, 2019USD ($)$ / shares	May 15, 2019MW	May 15, 2019kW	May 15, 2019property	May 15, 2019mi	May 15, 2019USD ($)	Apr. 30, 2019USD ($)	Feb. 19, 2019USD ($)	Jun. 30, 2019USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)mikW	Sep. 30, 2018USD ($)
Business Acquisition [Line Items]
Repayment of debt															$ 742	$ 825
Members contribution		$ 70							$ 1,330	$ 70	$ 70				1,540	144
Cash paid															1,324
InfraREIT Acquisition related costs															9
Revenue													$ 1,211	$ 1,095	3,268	3,106
Net income													263	$ 194	518	$ 426
Subsequent Event [Member]
Business Acquisition [Line Items]
Members contribution	$ 98
Sempra Texas Holdings [Member]
Business Acquisition [Line Items]
Members contribution									$ 1,330
InfraREIT [Member]
Business Acquisition [Line Items]
Price per share of common stock to stockholders and limited partners | $ / shares				$ 21
Purchase price				$ 1,324											$ 1,324
Management agreement termination fee				40
Repayment of debt			$ 602	288
Outstanding debt acquired				351
Transmission of assets				$ 2,545
Miles of assets transferred | mi								340							1,575
Cash paid															$ 1,275
Number of assets transferred in circuit miles | mi															1,235
Power of number of transmission lines transferred					3,900	138									345
Number Of Operational Generation Facilities | property							20
Number Of Transmission Stations And Substations | property							50
Goodwill, Period Increase (Decrease)													$ (12)
Revenue												$ 93
Net income												$ 36

Infrareit Acquisition (Total Pu

Infrareit Acquisition (Total Purchase Price Paid) (Details) - USD ($) $ in Millions	May 16, 2019	Sep. 30, 2019
Purchase of outstanding InfrREIT shares and units		$ 1,324
InfraREIT [Member]
Purchase of outstanding InfrREIT shares and units		1,275
Certain transaction costs of InfraREIT paid by Oncor		49
Total purchase price paid	$ 1,324	1,324
Management termination fee		$ 40

Infrareit Acquisition (Assets A

Infrareit Acquisition (Assets And Liabilities Assumed) (Details) - USD ($) $ in Millions	May 16, 2019	Sep. 30, 2019	Dec. 31, 2018
Goodwill		$ 4,739	$ 4,064
InfraREIT [Member]
Current assets	$ 44
Property, plant and equipment - net	1,800
Goodwill	675
Regulatory assets	16
Other noncurrent assets	10
Total assets acquired	2,545
Short-term debt	114
Other current liabilities	22
Regulatory liabilities	148
Liability in lieu of deferred income taxes	98
Long-term debt, including due currently	839
Total liabilities assumed	1,221
Net assets acquired	1,324
Total purchase price paid	$ 1,324	$ 1,324

Infrareit Acquisition (Pro Form

Infrareit Acquisition (Pro Forma Information) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
InfraREIT [Member]
Oncor Consolidated Pro Forma Revenues	$ 3,352	$ 3,268