Oncor Electric Delivery 10-K 26 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 26, 2019
Entity Registrant Name	ONCOR ELECTRIC DELIVERY CO LLC
Entity Central Index Key	1,193,311
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		0
Entity Current Reporting Status	No
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	Yes
Entity Public Float	$ 0
Oncor 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		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	[1]	Dec. 31, 2016
Total operating revenues		$ 4,101	$ 3,958		$ 3,920	[1]
Operating expenses:
Wholesale transmission service		962	929		894	[1]
Operation and maintenance (Note 12)		875	731		726	[1]
Depreciation and amortization		671	762		785	[1]
Provision in lieu of income taxes (Notes 1,5 and 12)		152	266		269	[1]
Taxes other than amounts related to income taxes		496	462		451	[1]
Total operating expenses		3,156	3,150		3,125	[1]
Operating income		945	808		795	[1]
Other income and (deductions) - net (Note 13)		(84)	(46)		(43)	[1]
Nonoperating provision (benefit) in lieu of income taxes (Note 5)		(35)	1		(15)	[1]
Interest expense and related charges (Note 13)		351	342		336	[1]
Net income		545	419		431	[1]
Nonaffiliates [Member]
Total operating revenues		$ 4,101	$ 3,958		3,205	[1]
Affiliates [Member]
Total operating revenues	[1]				$ 715
[1]	As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.

Condensed Statements Of Conso_2

Condensed Statements Of Consolidated Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Condensed Statements Of Consolidated Comprehensive Income [Abstract]
Net income	$ 545	$ 419	[1]	$ 431	[1]
Other comprehensive income (loss):
Cash flow hedges – derivative value net loss recognized in net income (net of tax expense of $1, $1 and $1) (Note 1)	2	2		2
Defined benefit pension plans (net of tax (benefit) expense of ($45), $4 and $-) (Note 10)	(65)	8
Total other comprehensive income (loss)	(63)	10		2
Comprehensive income	$ 482	$ 429		$ 433
[1]	As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.

Condensed Statements Of Conso_3

Condensed Statements Of Consolidated Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Statements Of Consolidated Comprehensive Income [Abstract]
Cash flow hedges - derivative value net loss recognized in net income, tax expense	$ 1	$ 1	$ 1
Defined benefit pension plans- net tax benefit	$ 45	$ 4

Condensed Statements Of Conso_4

Condensed Statements Of Consolidated Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Cash flows - operating activities:
Net income	$ 545	$ 419	[1]	$ 431	[1]
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	777	815		833
Provision in lieu of deferred income taxes	18	309		181
Other - net	(3)	(2)		(4)
Changes in operating assets and liabilities:
Accounts receivable - trade (including affiliates)	68	(76)		(34)
Inventories	(25)	(1)		(7)
Accounts payable - trade (including affiliates)	30	(11)		14
Regulatory accounts related to reconcilable tariffs (Note 3)	66	29		(55)
Other - assets	33	54		37
Other - liabilities	(27)	(77)		33
Cash provided by operating activities	1,482	1,459		1,429
Cash flows - financing activities:
Issuances of long-term debt (Note 7)	1,150	600		175
Repayments of long-term debt (Note 7)	(825)	(324)		(41)
Net (decrease) increase in short-term borrowings (Note 6)	(137)	161		(51)
Capital contributions from members (Note 9)	284
Distributions to members (Note 9)	(209)	(237)		(230)
Debt discount, premium, financing and reacquisition costs - net	(14)	(10)		10
Cash provided by (used in) financing activities	249	190		(137)
Cash flows - investing activities:
Capital expenditures (Note 12)	(1,767)	(1,631)		(1,352)
Business acquisition (Note 14)		(25)
Other - net	18	12		51
Cash used in investing activities	(1,749)	(1,644)		(1,301)
Net change in cash and cash equivalents	(18)	5		(9)
Cash and cash equivalents - beginning balance	21	16		25
Cash and cash equivalents - ending balance	$ 3	$ 21		$ 16
[1]	As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 3	$ 21
Trade accounts receivable - net (Note 13)	559	635
Amounts receivable from members related to income taxes (Note 12)		26
Materials and supplies inventories - at average cost	116	91
Prepayments and other current assets	94	88
Total current assets	772	861
Investments and other property (Note 13)	120	113
Property, plant and equipment - net (Note 13)	16,090	14,879
Goodwill (Notes 1 and 13)	4,064	4,064
Regulatory assets (Note 3)	1,691	2,180
Other noncurrent assets	15	23
Total assets	22,752	22,120
Current liabilities:
Short-term borrowings (Note 6)	813	950
Long-term debt due currently (Note 7)	600	550
Trade accounts payable (Note 12)	300	242
Amounts payable to members related to income taxes (Note 12)	26	21
Accrued taxes other than amounts related to income	199	190
Accrued interest	68	83
Other current liabilities	209	188
Total current liabilities	2,215	2,224
Long-term debt, less amounts due currently (Note 7)	5,835	5,567
Liability in lieu of deferred income taxes (Notes 1, 5 and 12)	1,602	1,517
Regulatory liabilities (Note 3)	2,697	2,807
Employee benefit obligations and other (Notes 10 and 13)	1,943	2,102
Total liabilities	14,292	14,217
Commitments and contingencies (Note 8)
Membership interests (Note 9):
Capital account — number of interests outstanding 2018 and 2017 - 635,000,000	8,624	8,004
Accumulated other comprehensive loss	(164)	(101)
Total membership interests	8,460	7,903
Total liabilities and membership interests	$ 22,752	$ 22,120

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - shares shares in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Consolidated Balance Sheets [Abstract]
Capital account, interests outstanding	635	635	635

Statements Of Consolidated Memb

Statements Of Consolidated Membership Interests - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Capital account:
Balance at beginning of period		$ 8,004		$ 7,822	$ 8,004	$ 7,822		$ 7,621
Net income	$ 119	89	$ 77	73	545	419	[1]	431	[1]
Capital contributions from members (Note 9)					284
Distributions to members (Note 9)					(209)	(237)		(230)
Balance at end of period (number of interests outstanding: 2018, 2017 and 2016 – 635 million)	8,624		8,004		8,624	8,004		7,822
Accumulated other comprehensive income (loss) net of tax effects (Note 9):
Balance at beginning of period		$ (101)		$ (111)	(101)	(111)		(113)
Net effects of cash flow hedges (net of tax expense of $1, $1 and $1)					2	2		2
Defined benefit pension plans (net of tax (benefit) expense of ($45), $4 and $-) (Note 10)					(65)	8
Balance at end of period	(164)		(101)		(164)	(101)		(111)
Total membership interests at end of period	$ 8,460		$ 7,903		$ 8,460	$ 7,903		$ 7,711
[1]	As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.

Statements Of Consolidated Me_2

Statements Of Consolidated Membership Interests (Parenthetical) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statements Of Consolidated Membership Interest [Abstract]
Interests outstanding	635	635	635
Net effects of cash flow hedges, tax expense	$ 1	$ 1	$ 1
Defined benefit pension plans- net tax benefit	$ 45	$ 4

Description Of Business and Sig

Description Of Business and Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Description Of Business and Significant Accounting Policies [Abstract]
DESCRIPTION OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES	1. DESCRIPTION OF BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES  Description of Business  References in this report to “we,” “our,” “us” and “the company” are to Oncor and/or its subsidiaries as apparent in the context. See “Glossary” for definition of terms and abbreviations.  We are a regulated electricity transmission and distribution company principally engaged in providing delivery services to REPs that sell power in the north-central, eastern and western parts of Texas. 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 2016 consolidated financial statements include our former wholly-owned, bankruptcy-remote financing subsidiary, Bondco, a VIE through December 29, 2016, at which time it was dissolved (see Note 13) . This financing subsidiary was organized for the limited purpose of issuing certain transition bonds to recover generation-related regulatory asset stranded costs and other qualified costs under an order issued by the PUCT in 2002. Bondco issued an aggregate $1.3 billion principal amount of transition bonds during 2003 and 2004. The 2003 Series transition bonds matured and were paid in full in 2015 and the 2004 Series transition bonds matured and were paid in full in May 2016. Final true-up proceedings and refunds of over-collected transition charges for the transition bonds were conducted by Oncor and the PUCT during 2016 and had no material net income impact.  Various “ring-fencing” measures have been taken to enhance 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. For more information on the ring-fencing measures, see Note 2.  EFH Bankruptcy Proceedings and Sempra Acquisition  In April 2014, EFH Corp. and the substantial majority of its direct and indirect subsidiaries at the time, including EFIH, EFCH and TCEH, commenced proceedings under Chapter 11 of the U.S. Bankruptcy Code. The Oncor Ring-Fenced Entities were not parties to the EFH Bankruptcy Proceedings. In connection with the plans of reorganization in the EFH Bankruptcy Proceedings, on March 9, 2018, the Sempra Acquisition was completed. See Note 2 for further information.  Basis of Presentation  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 year.  Revenue Recognition  General  Oncor’s revenue is billed under tariffs approved by the PUCT and the majority of revenues are related to providing electric delivery service to consumers. Tariff rates are designed to recover the cost of providing electric delivery service including a reasonable rate of return on invested capital. Revenues are generally recognized when the underlying service has been provided in an amount prescribed by the related tariff.  Reconcilable Tariffs  The PUCT has designated certain tariffs (TCRF, EECRF and previously AMS surcharges and charges related to transition bonds) as reconcilable, which means the differences between amounts billed under these tariffs and the related incurred costs are deferred as either regulatory assets or regulatory liabilities. Accordingly, at prescribed intervals, future tariffs are adjusted to either repay regulatory liabilities or collect regulatory assets. See “Regulatory Assets and Liabilities” below.  See Note 4 for additional information regarding revenues.  Impairment of Long-Lived Assets and Goodwill  We evaluate long-lived assets (including intangible assets with finite lives) for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. We also evaluate goodwill for impairment annually and whenever events or changes in circumstances indicate that an impairment may exist. The determination of the existence of these and other indications of impairment involves judgments that are subjective in nature and may require the use of estimates in forecasting future results and cash flows. Beginning in 2018, we elected to change our annual goodwill assessment date from December 1 to October 1 to correspond with the assessment date of our new majority owner. We do not believe this change in the assessment date is a material change.  If at the assessment date our carrying value exceeds our estimated fair value (enterprise value), then the estimated enterprise value is compared to the estimated fair values of our operating assets (including identifiable intangible assets) and liabilities at the assessment date. The resultant implied goodwill amount is compared to the recorded goodwill amount. Any excess of the recorded goodwill amount over the implied goodwill amount is written off as an impairment charge.  In October 2018, December 2017 and December 2016, we concluded, based on a qualitative assessment, that our estimated enterprise fair value was more likely than not greater than our carrying value. As a result , no additional testing for impairment was required and n o impairments were recognized in 2018, 2017 or 2016 .  Provision in Lieu of Income Taxes  Our tax sharing agreement with Oncor Holdings, Texas Transmission and STH (as successor to EFH Corp.) provides for the calculation of amounts related to income taxes for each of Oncor Holdings and Oncor substantially as if these entities were taxed as corporations and requires payments to the members determined on that basis (without duplication for any income taxes paid by a subsidiary of Oncor Holdings).  We are a partnership for U.S. federal income tax purposes and remain a partnership for U.S. federal income tax purposes after the closing of the Sempra Acquisition. Accordingly, while partnerships are not subject to income taxes, in consideration of the presentation of our financial statements as an entity subject to cost-based regulatory rate-setting processes, with such costs historically including income taxes, the financial statements present amounts determined under the tax sharing agreement as “provision in lieu of income taxes” and “liability in lieu of deferred income taxes”. Such amounts are determined in accordance with the provisions of the accounting guidance for income taxes and accounting standards that provide interpretive guidance for accounting for uncertain tax positions and thus differences between the book and tax bases of assets and liabilities are accounted for as if we were a stand-alone corporation. 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.  We classify any interest and penalties expense related to uncertain tax positions as current provision in lieu of income taxes as discussed in Note 5.  Defined Benefit Pension Plans and OPEB Plans  We have liabilities under pension plans that offer benefits based on either a traditional defined benefit formula or a cash balance formula and OPEB plans that offer certain health care and life insurance benefits to eligible employees and their eligible dependents upon the retirement of such employees from the company. Costs of pension and OPEB plans are dependent upon numerous factors, assumptions and estimates. See Note 10 for additional information regarding pension and OPEB plans.  System of Accounts  Our accounting records have been maintained in accordance with the FERC Uniform System of Accounts as adopted by the PUCT.  Property, Plant and Equipment  Properties are stated at original cost. The cost of self-constructed property additions includes materials and both direct and indirect labor and applicable overhead and an allowance for funds used during construction.  D epreciation of property, plant and equipment is calculated on a straight-line basis over the estimated service lives of the properties based on depreciation rates approved by the PUCT. As is common in the industry, depreciation expense is recorded using composite depreciation rates that reflect blended estimates of the lives of major asset groups as compared to depreciation expense calculated on a component asset-by-asset basis. Depreciation rates include plant removal costs as a component of depreciation expense, consistent with regulatory treatment. Actual removal costs incurred are charged to accumulated depreciation. Accrued removal costs in excess of incurred removal costs are reclassified as a regulatory liability to retire assets in the future.  Regulatory Assets and Liabilities  We are subject to rate regulation and our financial statements reflect regulatory assets and liabilities in accordance with accounting standards related to the effect of certain types of regulation. Regulatory assets and liabilities represent probable future revenues that will be recovered from or refunded to customers through the ratemaking process based on PURA and/or the PUCT’s orders, precedents or substantive rules. Rate regulation is premised on the full recovery of prudently incurred costs and a reasonable rate of return on invested capital subject to PUCT review for reasonableness and prudence and possible disallowance. Regulatory decisions can have an impact on the recovery of costs, the rate earned on invested capital and the timing and amount of assets to be recovered by rates. See Note 3 for more information regarding regulatory assets and liabilities.  Franchise Taxes  Franchise taxes are assessed to us by local governmental bodies, based on kWh delivered and are a principal component of taxes other than amounts related to income taxes as reported in the income statement. Franchise taxes are not a “pass through” item. The rates we charge customers are intended to recover the franchise taxes, but we are not acting as an agent to collect the taxes from customers.  Allowance for Funds Used During Construction (AFUDC)  AFUDC is a regulatory cost accounting procedure whereby both interest charges on borrowed funds and a return on equity capital used to finance construction are included in the recorded cost of utility plant and equipment being constructed. AFUDC is capitalized on all projects involving construction periods lasting greater than thirty days. The equity portion, if any, of capitalized AFUDC is accounted for as other income. See Note 13 for detail of amounts reducing interest expense.  Cash and Cash Equivalents  For purposes of reporting cash and cash equivalents, temporary cash investments purchased with an original maturity of three months or less are considered to be cash equivalents.  Fair Value of Nonderivative Financial Instruments  The carrying amounts for financial assets classified as current assets and the carrying amounts for financial liabilities classified as current liabilities approximate fair value due to the short maturity of such instruments. The fair values of other financial instruments, for which carrying amounts and fair values have not been presented, are not materially different than their related carrying amounts. The following discussion of fair value accounting standards applies primarily to our determination of the fair value of assets in the pension and OPEB plans’ trusts (see Note 10) and long-term debt (see Note 7).  Accounting standards related to the determination of fair value define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. We use a “mid-market” valuation convention (the mid-point price between bid and ask prices) as a practical expedient to measure fair value for the majority of our assets and liabilities subject to fair value measurement on a recurring basis. We primarily use the market approach for recurring fair value measurements and use valuation techniques to maximize the use of observable inputs and minimize the use of unobservable inputs.  We categorize our assets and liabilities recorded at fair value based upon the following fair value hierarchy:  · Level 1 valuations use quoted prices in active markets for identical assets or liabilities that are accessible at the measurement date. An active market is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis.  · Level 2 valuations use inputs that, in the absence of actively quoted market prices, are observable for the asset or liability, either directly or indirectly. Level 2 inputs include: (a) quoted prices for similar assets or liabilities in active markets , (b) quoted prices for identical or similar assets or liabilities in markets that are not active, (c) inputs other than quoted prices that are observable for the asset or liability such as interest rates and yield curves observable at commonly quoted intervals and (d) inputs that are derived principally from or corroborated by observable market data by correlation or other means. Our Level 2 valuations utilize over-the-counter broker quotes, quoted prices for similar assets or liabilities that are corroborated by correlations or other mathematical means and other valuation inputs.  · Level 3 valuations use unobservable inputs for the asset or liability. Unobservable inputs are used to the extent observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date. We use the most meaningful information available from the market combined with internally developed valuation methodologies to develop our best estimate of fair value.  We utilize several different valuation techniques to measure the fair value of assets and liabilities, relying primarily on the market approach of using prices and other market information for identical and/or comparable assets and liabilities for those items that are measured on a recurring basis.  The fair value of certain investments is measured using the net asset value (NAV) per share as a practical expedient. Such investments measured at NAV are not required to be categorized within the fair value hierarchy.  Consolidation of Variable Interest Entities  A VIE is an entity with which we have a relationship or arrangement that indicates some level of control over the entity or results in economic risks to us. We consolidate a VIE if we have: a) the power to direct the significant activities of the VIE and b) the right or obligation to absorb profit and loss from the VIE (primary beneficiary). See Note 13.  Derivative Instruments and Mark-to-Market Accounting  We have from time-to-time entered into derivative instruments to hedge interest rate risk. If the instrument meets the definition of a derivative under accounting standards related to derivative instruments and hedging activities, the fair value of each derivative is recognized on the balance sheet as a derivative asset or liability and changes in the fair value are recognized in net income, unless criteria for certain exceptions are met. This recognition is referred to as “mark-to-market” accounting. Changes in Accounting Standards  Topic 606, “Revenue from Contracts with Customers” - Since May 2014, the Financial Accounting Standards Board (FASB) has issued Accounting Standards Update (ASU) 2014-09, along with other supplemental guidance (together, Topic 606). Topic 606 introduced new, increased requirements for disclosure of revenue in financial statements and guidance intended to eliminate inconsistencies in the recognition of revenue. We adopted Topic 606 effective January 1, 2018 using the modified retrospective approach and elected the practical expedient available that allows an entity to recognize revenue in the amount to which the entity has the right to invoice related to performance completed to date. Our revenues are generally recognized when the underlying service has been provided in an amount prescribed by the related tariff. The new guidance did not change this pattern of recognition and therefore the adoption did not have a material effect on our reported results of operations, financial position or cash flows. Topic 606 also requires the separate presentation of “alternative revenue program” revenues on the income statement. We recorded $7 million in alternative revenue program revenues in 2018 related to our energy efficiency program and disclosed such activity in Note 4. See Note 4 for additional disclosures about revenues from contracts with customers.  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 regulatory purposes. Under current standards, all of Oncor’s existing leases meet the definition of an operating lease. Under the new rules, the recognition of any finance leases (currently known as capital leases) on the balance sheet would be classified as debt for GAAP purposes and are expected to be defined as debt for our regulatory capital structure purposes (see Note 9 for details) similar to the current capital lease treatment. We adopted Topic 842 on January 1, 2019 and will use certain practical expedients and policy elections available under the guidance including a practical expedient to not assess whether existing land easements that were not previously accounted for as leases are or contain a lease under Topic 842, an adoption method to not restate comparative periods and a policy election to forego the application of Topic 842 recognition requirements to short-term leases. The initial adoption of Topic 842 will affect our 2019 balance sheet, as our contracts for office space and fleet vehicles are currently classified as operating leases. The initial adoption of Topic 842 is expected to result in the recording of operating lease assets and operating lease obligations each in the amount of approximately $100 million with no impact to results of operations or cash flows.  Topic 715, “Compensation – Retirement Benefits” amended by ASU 2017-07, “Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost” - In March 2017, the FASB issued ASU 2017-07, an amendment to Topic 715. ASU 2017-07 requires the non-service cost components of net retirement benefit plan costs be presented as non-operating in the income statement. In addition, only the service cost component of net retirement benefit plan cost is eligible for capitalization as part of inventory or property, plant and equipment. We adopted ASU 2017-07 on January 1, 2018. The presentation of costs is required to be applied on a retrospective basis while the capitalization eligibility requirement is applied on a prospective basis. The guidance allows a practical expedient that permits use of previously disclosed service costs and non-service costs of the Pension and OPEB Plans in the comparative periods as appropriate estimates when recasting the presentation of these costs in the income statements. We have elected this practical expedient. For cash flow purposes on a prospective basis, non-service costs will be reflected as a reduction to operating cash flows, offset by lower cash used in investing activities (lower capital expenditures). The new guidance did not have a material effect on our results of operations, financial position or net change in total cash flows and we do not expect the guidance to have a material effect on our rate-making process. For the years 2016 and 2017, the adoption of ASU 2017-07 resulted in a reclassification of expense of $28 million and $31 million from operation and maintenance expense to other income and (deductions), respectively, and a corresponding reclassification of benefit of $10 million and $11 million, respectively, from provision in lieu of income taxes to nonoperating provision in lieu of income taxes.  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. ASU 2018-02 allows a reclassification from accumulated other comprehensive income (AOCI) to capital accounts for stranded tax effects resulting from the TCJA which we expect to elect. Under ASU 2018-02, an entity will be required to provide certain disclosures regarding stranded tax effects, including its accounting policy related to releasing the income tax effects from AOCI. Our stranded tax effects in AOCI are approximately $4 million and will increase our capital account upon reclassification. ASU 2018-02 can be applied either as of the beginning of the period of adoption or retrospectively as of the date of enactment of the TCJA and to each period in which the effect of the TCJA is recognized. ASU 2018-02 is effective for our 2019 annual reporting period, including interim periods therein, with early adoption permitted. We adopted the standard on a prospective basis, January 1, 2019. 

EFH Bankruptcy Proceedings and

EFH Bankruptcy Proceedings and Sempra Acquisition	12 Months Ended
	Dec. 31, 2018
EFH Bankruptcy Proceedings and Sempra Acquisition [Abstract]
EFH BANKRUPTCY PROCEEDINGS AND SEMPRA ACQUISITION	2. EFH BANKRUPTCY PROCEEDINGS AND SEMPRA ACQUISITION  In April 2014, EFH Corp. and the substantial majority of its direct and indirect subsidiaries at the time, including EFIH, EFCH and TCEH, commenced proceedings under Chapter 11 of the U.S. Bankruptcy Code. The Oncor Ring-Fenced Entities were not parties to the EFH Bankruptcy Proceedings. In 2016, pursuant to a plan of reorganization confirmed by the bankruptcy court, the TCEH Debtors exited bankruptcy pursuant to the Vistra Spin-Off. As a result of the Vistra Spin-Off, Vistra and its subsidiaries, including Luminant and TXU Energy, ceased to be related parties of ours as of October 3, 2016. See Note 12 for details of Oncor’s related-party transactions with members of the Texas Holdings Group. In connection with the plans of reorganization in the EFH Bankruptcy Proceedings, on March 9, 2018, the Sempra Acquisition occurred and Sempra acquired the 80.03% of Oncor’s membership interests owned indirectly by EFH Corp. and EFIH as discussed in further detail below. Prior to consummation of the Sempra Acquisition, EFH Corp. had filed and confirmed other plans of reorganization and entered into various merger agreements with other parties in connection with the EFH Bankruptcy Proceedings that contemplated the transfer of its indirect ownership interest in Oncor, but those agreements were terminated and the contemplated transactions failed to close.  Sempra Acquisition  In August 2017, EFH Corp. and EFIH entered into an Agreement and Plan of Merger (Sempra Merger Agreement) with Sempra and one of its wholly-owned subsidiaries (collectively, the Sempra Parties) that contemplated the Sempra Parties acquiring the ownership interests in Oncor that were indirectly held by EFH Corp. The Sempra Acquisition closed on March 9, 2018 after obtaining the approval of the bankruptcy court in the EFH Bankruptcy Proceedings, the Federal Communications Commission and the PUCT. As a result of the Sempra Acquisition, EFH Corp. merged with an indirect subsidiary of Sempra, with EFH Corp. (renamed STH) continuing as the surviving company and an indirect, wholly-owned subsidiary of Sempra. The Sempra Merger Agreement did not impose any conditions on the EFH Debtors regarding Texas Transmission’s minority interest in Oncor. Accordingly, the Sempra Merger Agreement provided for the acquisition by Sempra of the 80.03% of Oncor’s membership interests owned indirectly by EFH Corp. and EFIH. In accordance with the Sempra Merger Agreement, Sempra paid cash consideration of approximately $9.45 billion to acquire the indirect 80.03% outstanding membership interest in Oncor. In addition, in a separate transaction, Oncor Holdings acquired 0.22% of the outstanding membership interests in Oncor from Investment LLC. After the Sempra Acquisition, Texas Transmission continued to own 19.75% of Oncor’s outstanding membership interests.  Pursuant to the terms of the Sempra Merger Agreement, in October 2017, Oncor and Sempra filed in PUCT Docket No 47675 a joint application with the PUCT seeking certain regulatory approvals with respect to the transactions contemplated by the amended joint plan of reorganization filed in September 2017 by the EFH Debtors (Sempra Plan). At its open meeting on March 8, 2018, the PUCT approved a final order adopting a settlement stipulation allowing the Sempra Acquisition to proceed. For more information regarding the Sempra Settlement Stipulation and the proceedings in PUCT Docket No. 47675, see “Sempra PUCT Proceedings” below.  In connection with the closing of the Sempra Acquisition, Oncor’s Limited Liability Company Agreement was amended and restated in its entirety on March 9, 2018. The Limited Liability Company Agreement, among other things, provides for the management of Oncor by a board of directors consisting of 13 members, including seven “disinterested directors” (as defined in the Limited Liability Company Agreement), two directors designated indirectly by Sempra, two directors designated by Texas Transmission (subject to certain conditions) and two directors that are current or former officers of Oncor.  Management Equity Purchase  On March 9, 2018, Oncor entered into an Interest Transfer Agreement (OMI Agreement) with Investment LLC, Oncor Holdings and Sempra. Pursuant to the 2008 Equity Interests Plan for Key Employees of Oncor Electric Delivery Company LLC and its affiliates, certain members of Oncor’s management, including Oncor’s executive officers and disinterested directors on Oncor’s board of directors, were granted the opportunity to purchase Class B equity interests (Class B Interests) in Investment LLC, an entity whose only assets consist of equity interests in Oncor. Investment LLC held 1,396,008 of the outstanding limited liability company interests in Oncor (the OMI Interests), which represented 0.22% of the outstanding membership interests in Oncor.  Pursuant to the OMI Agreement, concurrent with the closing of the Sempra Acquisition, Investment LLC transferred to Oncor Holdings all of the OMI Interests in exchange for $26 million in cash, which represents approximately $18.60 for each OMI Interest.  PUCT Matters Related to Sempra Acquisition  Pursuant to the terms of the Sempra Merger Agreement, in October 2017 Oncor and Sempra filed in PUCT Docket No. 47675 a joint application with the PUCT seeking certain regulatory approvals with respect to the Sempra Plan. In December 2017, Oncor and Sempra entered into a stipulation with the Staff of the PUCT, the Office of Public Utility Counsel, the Steering Committee of Cities Served by Oncor and the Texas Industrial Energy Consumers reflecting the parties’ settlement of all issues in the PUCT proceeding regarding the joint application. On January 5, 2018, Oncor, Sempra and the Staff of the PUCT made a joint filing with the PUCT requesting that the PUCT approve the acquisition, consistent with the governance, regulatory and operating commitments in a revised stipulation joined by two additional parties. On January 23, 2018, Oncor and Sempra filed an additional revision to the revised stipulation (Sempra Settlement Stipulation) and announced that two more parties had joined in the Sempra Settlement Stipulation. On February 2, 2018, Oncor and Sempra announced that all of the intervenors in PUCT Docket No. 47675 had signed on to the Sempra Settlement Stipulation. At its February 15, 2018 open meeting, the PUCT directed PUCT Staff to prepare an order based on the Sempra Settlement Stipulation for consideration by the PUCT at its open meeting on March 8, 2018. At the open meeting, the PUCT approved the final order.  T he parties to the Sempra Settlement Stipulation agreed that Sempra’s acquisition of EFH Corp. was in the public interest and would bring substantial benefits. The Sempra Settlement Stipulation requested that the PUCT approve the Sempra Acquisition. The joint application filed with the PUCT, the Sempra Settlement Stipulation and the Sempra Order outline certain ring-fencing measures, governance mechanisms and restrictions that apply after the Sempra Acquisition. As a result of these ring-fencing measures, Sempra does not control Oncor, and the ring-fencing measures limit Sempra’s ability to direct the management, policies and operations of Oncor, including the deployment or disposition of Oncor’s assets, declarations of dividends, strategic planning and other important corporate issues and actions. These limitations include limited representation on the board of directors of Oncor.  Pursuant to the Sempra Order, following the consummation of the Sempra Acquisition, the board of directors of Oncor is required to consist of thirteen members and be constituted as follows: · seven members, which we refer to as disinterested directors, who (i) shall be independent directors in all material respects under the rules of the New York Stock Exchange in relation to Sempra or its subsidiaries and affiliated entities and any entity with a direct or indirect ownership interest in Oncor or Oncor Holdings, and (ii) shall have no material relationship with Sempra or its subsidiaries or affiliated entities or any entity with a direct or indirect ownership interest in Oncor or Oncor Holdings, currently or within the previous ten years; · two members shall be designated by Sempra (through Oncor Holdings); · two members shall be appointed by Texas Transmission; and · two members shall be current or former officers of Oncor (the Oncor Officer Directors), initially Robert S. Shapard and E. Allen Nye, Jr., who are the Chairman of the Board and Chief Executive, respectively.  In order for a current or former officer of Oncor to be eligible to serve as an Oncor Officer Director, the officer cannot have worked for Sempra or any of its affiliates (excluding Oncor Holdings and Oncor) or any other entity with a direct or indirect ownership interest in Oncor or Oncor Holdings in the ten-year period prior to the officer being employed by Oncor. Oncor Holdings, at the direction of STIH, has the right to nominate and/or seek the removal of the Oncor Officer Directors, subject to approval by a majority of the Oncor board of directors. STIH is a wholly-owned indirect subsidiary of, and controlled by, Sempra following the Sempra Acquisition.  In addition, the Sempra Order provides that Oncor’s board cannot be overruled by the board of Sempra or any of its subsidiaries on dividend policy, the issuance of dividends or other distributions (except for contractual tax payments), debt issuance, capital expenditures, operation and maintenance expenditures, management and service fees, and appointment or removal of board members, provided that certain actions may also require the additional approval of the Oncor Holdings board of directors. The Sempra Order also provides that any changes to the size, composition, structure or rights of the board must first be approved by the PUCT. In addition, if Sempra acquires Texas Transmission’s interest in Oncor, the two board positions on Oncor’s board of directors that Texas Transmission is entitled to appoint will be eliminated and the size of Oncor’s board of directors will be reduced by two.  Additional regulatory commitments, governance mechanisms and restrictions provided in the Sempra Order include, among others:  · A majority of the disinterested directors of Oncor must approve any annual or multi-year budget if the aggregate amount of capital expenditures or operating and maintenance expenditures in such budget is more than a 10% increase or decrease from the corresponding amounts of such expenditures in the budget for the preceding fiscal year or multi-year period, as applicable;  · Oncor will make minimum aggregate capital expenditures equal to at least $7.5 billion over the period from January 1, 2018 through December 31, 2022 (subject to certain possible adjustments);  · Sempra was required to make, within 60 days after the Sempra Acquisition, its proportionate share of the aggregate equity investment in Oncor in an amount necessary for Oncor to achieve a capital structure consisting of 57.5% long-term debt to 42.5% equity, as calculated for regulatory purposes, and pursuant to that requirement Sempra contributed $117 million in cash commensurate with its ownership interest to Oncor on April 23, 2018, as discussed in further detail in Note 9;  · Oncor may not pay any dividends or make any other distributions (except for contractual tax payments) if a majority of its disinterested directors determines that it is in the best interests of Oncor to retain such amounts to meet expected future requirements;  · At all times, Oncor will remain in compliance with the debt-to-equity ratio established by the PUCT from time to time for ratemaking purposes, and Oncor will not pay dividends or other distributions (except for contractual tax payments), if that payment would cause its debt-to-equity ratio to exceed the debt-to-equity ratio approved by the PUCT;  · If the credit rating on Oncor’s senior secured debt by any of the three major rating agencies falls below BBB (or the equivalent), Oncor will suspend dividends and other distributions (except for contractual tax payments), unless otherwise allowed by the PUCT;  · Without the prior approval of the PUCT, neither Sempra nor any of its affiliates (excluding Oncor) will incur, guaranty or pledge assets in respect of any indebtedness that is dependent on the revenues of Oncor in more than a proportionate degree than the other revenues of Sempra or on the stock of Oncor, and there will be no debt at STH or STIH at any time following the closing of the Sempra Acquisition;  · Neither Oncor nor Oncor Holdings will lend money to or borrow money from Sempra or any of its affiliates (other than Oncor subsidiaries), or any entity with a direct or indirect ownership interest in Oncor or Oncor Holdings, and neither Oncor nor Oncor Holdings will share credit facilities with Sempra or any of its affiliates (other than Oncor subsidiaries), or any entity with a direct or indirect ownership interest in Oncor or Oncor Holdings;  · Oncor will not seek recovery in rates of any expenses or liabilities related to EFH Corp.’s bankruptcy, or (1) any tax liabilities resulting from the Vistra Spin-Off, (2) any asbestos claims relating to non-Oncor operations of EFH Corp. or (3) any make-whole claims by holders of debt securities issued by EFH Corp. or EFIH, and Sempra was required to file with the PUCT a plan providing for the extinguishment of the liabilities described in items (1) through (3) above, which protects Oncor from any harm (which plan was filed with the PUCT on April 6, 2018 in PUCT Docket No. 48119);  · There must be maintained certain “separateness measures” that reinforce the financial separation of Oncor from STH and STH’s owners, including a requirement that dealings between Oncor, Oncor Holdings and their subsidiaries with Sempra, any of Sempra’s other affiliates or any entity with a direct or indirect ownership interest in Oncor or Oncor Holdings, must be on an arm’s-length basis, limitations on affiliate transactions, separate recordkeeping requirements and a prohibition on pledging Oncor assets or stock for any entity other than Oncor;  · No transaction costs or transition costs related to the Sempra Acquisition (excluding Oncor employee time) will be borne by Oncor’s customers nor included in Oncor’s rates;  · Sempra will continue to hold indirectly at least 51% of the ownership interests in Oncor and Oncor Holdings for at least five years following the closing of the Sempra Acquisition, unless otherwise specifically authorized by the PUCT; and  · Oncor will provide bill credits to electric delivery rates for ultimate credits to customers in an amount equal to 90% of any interest rate savings achieved due to any improvement in its credit ratings or market spreads compared to those as of June 30, 2017 until final rates are set in the next Oncor base rate case filed after PUCT Docket No. 46957 (except that savings will not be included in credits if already realized in rates); and one year after the Sempra Acquisition, Oncor will provide bill credits to electric delivery rates for inclusion in customer bills equal to 90% of any synergy savings until final rates are set in the next Oncor base rate proceeding after the 2017 rate review (PUCT Docket No. 46957), at which time any total synergy savings shall be reflected in Oncor’s rates. On September 7, 2018, Oncor filed its first semi-annual interest rate savings compliance report with the PUCT and began accruing a bill credit upon the issuance of its new senior secured notes in August 2018. 

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2018
Regulatory Matters [Abstract]
REGULATORY MATTERS	3. 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 December 31, 2018 are provided in the table below. Amounts not earning a return through rate regulation are noted.   Remaining Rate Recovery/Amortization Period at At December 31,  December 31, 2018 2018 2017   Regulatory assets:  Employee retirement liability (a)(b)(c) To be determined $ 648 $ 854  Employee retirement costs being amortized 9 years 297 331  Employee retirement costs incurred since the last rate review period (b) To be determined 73 30  Self-insurance reserve (primarily storm recovery costs) being amortized 9 years 351 394  Self-insurance reserve incurred since the last rate review period (b) To be determined 59 49  Securities reacquisition costs Lives of related debt 10 12  Deferred conventional meter and metering facilities depreciation 2 years 36 57  Under-recovered AMS costs 9 years 185 206  Excess deferred taxes Various - 197  Energy efficiency performance bonus (a) 1 year or less 7 12  Other regulatory assets Various 25 38  Total regulatory assets 1,691 2,180   Regulatory liabilities:  Estimated net removal costs Lives of related assets 1,023 954  Excess deferred taxes Primarily over lives of related assets 1,571 1,789  Over-recovered wholesale transmission service expense (a) 1 year or less 89 47  Other regulatory liabilities Various 14 17  Total regulatory liabilities 2,697 2,807  Net regulatory assets (liabilities) $ (1,006) $ (627) ____________ (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.  The excess deferred tax related balances are primarily the result of the TCJA corporate federal income tax rate reduction from 35% to 21%. These regulatory assets and 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 future tariffs.  DCRF (PUCT Docket No. 48231)  On April 5, 2018, we filed with the PUCT, as well as cities with original jurisdiction over Oncor’s rates, an application for approval of a DCRF. The DCRF will allow Oncor to recover, primarily through its tariff for retail delivery service, certain costs related to its 2017 distribution investments. We requested a $19 million increase in annual distribution revenues in our DCRF application. On June 13, 2018, we filed an unopposed stipulation that reduced the annual distribution revenue increase from $19 million to $15 million. The PUCT approved the stipulation on August 30, 2018, and the distribution tariffs became effective September 1, 2018.  Application to Decrease Rates Based on the TCJA of 2017 (PUCT Dock e t No. 48325)  In 2018, we made filings to incorporate the impacts of the TCJA into our tariffs, including the reduced 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. The proposal included annual rate reductions of $144 million related to the reduction in income tax expense currently included in rates and $37 million related to the amortization of excess deferred income taxes over the lives of related assets. In September 2018, we reached an unopposed stipulation regarding an overall settlement of the TCJA impacts. The settlement includes, 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 have been implemented as follows on an interim basis pending final PUCT approval.  · For transmission customers, our TCOS rate incorporated the tax rate reduction beginning March 27, 2018. On July 1, 2018, a new interim TCOS rate was approved, subject to reconciliation, including a reduction due to amortization of excess deferred federal income taxes. The settlement results in a reduction of about $79 million of annualized transmission base revenue requirement as compared to the revenue requirement approved in PUCT Docket No. 46957.  · For distribution customers, interim rates implemented October 8, 2018 contain reductions for both the income tax expense currently in rates and the amortization of excess deferred tax expense. The settlement results in a reduction of about $140 million of annualized distribution base revenue requirement as compared to the revenue requirement approved in PUCT Docket No. 46957.  In addition, we agreed to refund the tax rate differential amounts collected and deferred since January 1, 2018, through the date the changed tariffs became effective. For transmission customers, we refunded tax amounts collected and deferred through March 26, 2018. For distribution customers, we refunded tax amounts collected and deferred through October 7, 2018. In total, the tax rate differential of $73 million was refunded as a bill credit in December 2018.  The pass-through of the impacts of the TCJA to ratepayers is not expected to impact net income. Amortization of excess deferred taxes will result in lower cash inflows as a result of reduced rates to end-use customers.  2017 Rate Review (PUCT Docket No. 46957)  In response to resolutions passed by numerous cities with original jurisdiction over electric utility rates, we filed rate review proceedings with the PUCT and original jurisdiction cities in our service territory in March 2017 based on a January 1, 2016 to December 31, 2016 test year.  In July 2017, we and certain parties to our rate review agreed to a settlement of that rate review, and on August 2, 2017 a settlement agreement was filed with the PUCT that settled all issues in the docket. On October 13, 2017, the PUCT issued an order approving the settlement of the rate review, subject to closing of the Sharyland Asset Exchange, which closed on November 9, 2017. As a result of the Sharyland Asset Exchange closing on November 9, 2017, the contingency in the PUCT order in PUCT Docket No. 46957 was met and our new rates as set forth in that order took effect on November 27, 2017. The order also required us to record as a regulatory liability, instead of revenue, the amount that we collected through our approved tariffs for federal income taxes that was above the new corporate federal income rate. Other significant findings include a change in our authorized return on equity to 9.80% and a change in our authorized regulatory capital structure to 57.5% debt to 42.5% equity. Our previous authorized return on equity was 10.25% and our previous authorized regulatory capital structure was 60% debt to 40% equity. The PUCT order required us to record a regulatory liability from November 27, 2017 until the new authorized regulatory capital structure was met to reflect our actual capitalization prior to achieving the authorized capital structure. Our authorized regulatory capital structure was met in May 2018, and therefore we ceased accruing amounts to the capital structure refund regulatory liability as of that time. The regulatory liability of $6 million was approved on September 14, 2018 in PUCT Docket No. 48522, and the liability was subsequently returned to customers in September 2018.  Also, in accordance with the rate review final order, effective November 27, 2017, the AMS surcharge ceased and ongoing AMS costs are being recovered through base rates which include the recovery of the AMS regulatory asset over a 10-year period. We continue to recover previously approved retired conventional meters over time as a regulatory asset.  Sharyland Asset Exchange (PUCT Docket No. 47469)  On July 21, 2017, we entered into the Sharyland Agreement with the Sharyland Entities. The Sharyland Agreement provided that we would exchange certain of our transmission assets and cash for certain of the Sharyland Entities’ distribution assets (constituting substantially all of their electricity distribution business) and certain of their transmission assets. On October 13, 2017, the PUCT issued an order approving the Sharyland Asset Exchange and on November 9, 2017, the parties consummated the transactions. For more information on the Sharyland Agreement and the Sharyland Asset Exchange, see Note 14.  We are involved in various other regulatory proceedings in the normal course of business, the ultimate resolution of which, in the opinion of management, should not have a material effect upon our financial position, results of operations or cash flows.

Revenues

Revenues	12 Months Ended
	Dec. 31, 2018
Revenues [Abstract]
REVENUES	4. 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 units 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 (Topic 606 revenues) except for alternative revenue program revenues discussed below.  Reconcilable Tariffs  The PUCT has designated certain tariffs (primarily TCRF, EECRF and previously AMS surcharges and charges related to transition bonds) as reconcilable, which means the differences between amounts billed under these tariffs and the related incurred costs are deferred as either regulatory assets or regulatory liabilities. Accordingly, at prescribed intervals, future tariffs are adjusted to either repay regulatory liabilities or collect regulatory assets.  As a result of the 2017 rate review order effective November 27, 2017, the AMS surcharges ceased and AMS related expenses and return became recoverable through distribution base rates.  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 is considered an “alternative revenue program” for GAAP purposes and the related performance bonus revenues are outside of the scope of Topic 606. Annual performance bonuses are recognized as revenue when approved by the PUCT, typically in the third or fourth quarter each year. In 2018, the PUCT approved a $7 million bonus that we recognized in revenues in 2018.  Disaggregation of Revenues  The following table reflects electric delivery revenues disaggregated by tariff:    Year Ended December 31,  2018   Operating revenues  Revenues contributing to earnings:  Distribution base revenues $ 2,139  Transmission base revenues (TCOS revenues)  Billed to third-party wholesale customers 548  Billed to REPs serving Oncor distribution customers, through TCRF 310  Total transmission base revenues 858  Other miscellaneous revenues 71  Total revenues contributing to earnings 3,068   Revenues collected for pass-through expenses:  TCRF - third-party wholesale transmission service 962  EECRF and other regulatory charges 71  Revenues collected for pass-through expenses 1,033   Total operating revenues $ 4,101  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 benefitting from our transmission system. Our transmission customers consist of municipalities, electric cooperatives and other distribution companies. REP subsidiaries of our two largest counterparties represented 23% and 19% of our total operating revenues for the year ended 2018, 22% and 18% for the year ended 2017 and 23% and 17% for the year ended 2016. 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 nonaffiliated 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.

Provision In Lieu Of Income Tax

Provision In Lieu Of Income Taxes	12 Months Ended
	Dec. 31, 2018
Provision In Lieu Of Income Taxes [Abstract]
PROVISION IN LIEU OF INCOME TAXES	5. PROVISION IN LIEU OF INCOME TAXES  Tax Cuts and Jobs Act (TCJA)  On December 22, 2017, the TCJA was signed into law. Substantially all of the provisions of the TCJA are effective for our taxable years beginning January 1, 2018. The TCJA includes significant changes to the Code, including amendments which significantly change the taxation of business entities and includes specific provisions related to regulated public utilities such as Oncor. The most significant TCJA change that impacts us is the reduction in the corporate federal income tax rate from 35% to 21% . The specific provisions related to regulated public utilities in the TCJA applicable to us include the continued deductibility of interest expense, the elimination of bonus depreciation on certain property acquired after September 27, 2017 and certain rate normalization requirements for accelerated depreciation benefits.  Changes in the Code from the TCJA had a material impact on our financial statements in 2017. Under GAAP, specifically Topic 740, Income Taxes, the tax effects of changes in tax laws must be recognized when the law is enacted, or December 22, 2017 for the TCJA. Topic 740 also requires deferred tax assets and liabilities to be measured at the enacted tax rate expected to apply when temporary differences are to be realized or settled. Based on this, our liability in lieu of deferred income taxes was re-measured at the date of enactment using the new tax rate.  We have completed the measurement and accounting for the effects of the TCJA. The re-measurement of our liability in lieu of deferred income taxes related to our non-regulated operations resulted in a $21 million charge to the nonoperating provision in lieu of tax expense for the year ended December 31, 2017. The re-measurement of our liability in lieu of deferred income taxes related to our regulated operations resulted in a $1.6 billion decrease in our liability in lieu of deferred income taxes at December 22, 2017 and a corresponding increase in our regulatory liabilities.  Components of Liability in Lieu of Deferred Income Taxes  The components of our liability in lieu of deferred income taxes are provided in the table below.    At December 31,  2018 2017   Deferred Tax Related Assets:  Employee benefit liabilities $ 234 $ 253  Regulatory liabilities 55 15  Other 6 7  Total 295 275  Deferred Tax Related Liabilities:  Property, plant and equipment 1,651 1,551  Regulatory assets 245 240  Other 1 1  Total 1,897 1,792  Liability in lieu of deferred income taxes - net $ 1,602 $ 1,517  Provision (Benefit) in Lieu of Income Taxes  The components of our reported provision (benefit) in lieu of income taxes are as follows:   Year Ended December 31,  2018 2017 (1) 2016 (1)   Reported in operating expenses:  Current:  U.S. federal $ 112 $ (55) $ 60  State 21 20 20  Deferred:  U.S. federal 21 303 191  State - - -  Amortization of investment tax credits (2) (2) (2)  Total reported in operating expenses 152 266 269  Reported in other income and deductions:  Current:  U.S. federal (32) (5) (5)  State - - -  Deferred federal (3) 6 (10)  Total reported in other income and deductions (35) 1 (15)  Total provision in lieu of income taxes $ 117 $ 267 $ 254 ________________ (1) As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.  Reconciliation of provision in lieu of income taxes computed at the U.S. federal statutory rate to provision in lieu of income taxes:   Year Ended December 31,  2018 2017 2016   Income before provision in lieu of income taxes $ 662 $ 686 $ 685  Provision in lieu of income taxes at the U.S. federal statutory rate of 21% for 2018 and 35% for 2017 and 2016 $ 139 $ 240 $ 240  Amortization of investment tax credits – net of deferred tax effect (2) (2) (2)  Amortization of excess deferred taxes (18) (1) (1)  Impact of federal statutory rate change from 35% to 21% - 21 -  Texas margin tax, net of federal tax benefit 17 13 13  Nontaxable gains on benefit plan investments (1) (4) -  Other, including audit settlements (18) - 4  Reported provision in lieu of income taxes $ 117 $ 267 $ 254  Effective rate 17.7% 38.9% 37.1%  The net amounts of $1.602 billion and $1.517 billion reported in the balance sheets at December 31, 2018 and 2017, respectively, as liability in lieu of deferred income taxes include amounts previously recorded as net deferred tax liabilities. Upon the sale of equity interests to Texas Transmission and Investment LLC in 2008, we became a partnership for U.S. federal income tax purposes, and the temporary differences that gave rise to the deferred taxes will, over time, become taxable to the equity holders. Under a tax sharing agreement among us and our equity holders (see Note 1), we make payments to the equity holders related to income taxes when amounts would have become due to the IRS if Oncor was taxed as a corporation. Accordingly, as the temporary differences become taxable, we will pay the equity holders. In the event such amounts are not paid under the tax sharing agreement, it is probable that this regulatory liability will continue to be included in Oncor’s rate setting processes.  Accounting For Uncertainty in Provision in Lieu of Income Taxes  The statute of limitations is open for our partnership tax returns for the years beginning after December 31, 2009, however, the IRS has declined to review the tax returns for the years ended prior to January 1, 2016. Texas margin tax returns are under examination or still open for examination for tax years beginning after 2014. We are not a member of any consolidated federal tax group and assess our liability for uncertain tax positions in our partnership returns.  We had no uncertain tax positions in 2018. The following table summarizes the changes to the uncertain tax positions reported in other noncurrent liabilities in our consolidated balance sheet during the years ended December 31, 2017 and 2016:   2017 2016   Balance at January 1, excluding interest and penalties $ 3 $ 3  Reductions based on tax positions related to prior years (3) -  Balance at December 31, excluding interest and penalties $ - $ 3  As of December 31, 2016, the $3 million balance represents tax positions for which the uncertainty relates to the timing of recognition for tax purposes. In the first quarter 2017, EFH Corp. settled all open tax claims with the IRS. As a result, we reduced the liability for uncertain tax positions by $3 million. This reduction is reported as a decrease in income taxes in 2017.  Noncurrent liabilities included no accrued interest related to uncertain tax positions at December 31, 2018 and 2017. There were no amounts recorded related to interest and penalties in the years ended December 31, 2018, 2017 and 2016. The federal income tax benefit on the interest accrued on uncertain tax positions, if any, is recorded as liability in lieu of deferred income taxes.

Short-Term Borrowings

Short-Term Borrowings	12 Months Ended
	Dec. 31, 2018
Short-Term Borrowings [Abstract]
SHORT-TERM BORROWINGS	6. SHORT-TERM BORROWINGS  At December 31, 2018 and 2017, outstanding short-term borrowings under our commercial paper program (CP Program) and revolving credit facility (Credit Facility) consisted of the following:    At December 31,  2018 2017  Total borrowing capacity $ 2,000 $ 2,000  Commercial paper outstanding (a) (813) -  Credit facility outstanding (b) - (950)  Letters of credit outstanding (c) (9) (9)  Available unused credit $ 1,178 $ 1,041  ____________ a) The weighted average interest rate for commercial paper at December 31, 2018 was 2.74% . b) The weighted average interest rate for the Credit Facility at December 31, 2017 was 2.62% . c) Interest rates on outstanding letters of credit at December 31, 2018 and December 31, 2017 were 1.200% and 1.325% , respectively, based on our credit ratings.  CP Program  In March 2018, we established the CP Program, under which we may issue unsecured commercial paper notes (Notes) on a private placement basis up to a maximum aggregate face or principal amount outstanding at any time of $2.0 billion. We also entered into commercial paper dealer agreements (Dealer Agreements) with commercial paper dealers (Dealers). The Dealer Agreements are substantially identical in all material respects except as to the parties thereto. A national bank acts as the issuing and paying agent under the CP Program pursuant to the terms of an issuing and paying agent agreement.  The proceeds of 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 discussed below. If at any time funds are not available on favorable terms under the CP Program, we may utilize the Credit Facility for funding.  The Dealer Agreements provide the terms under which the Dealers will either purchase from us or arrange for the sale by us of Notes pursuant to an exemption from federal and state securities laws. The Dealer Agreements contain customary representations, warranties, covenants and indemnification provisions. The maturities of the Notes will vary, but may not exceed 364 days from the date of issue. The Notes will be sold at a discount from par or, alternatively, will be sold at par and bear interest. Interest rates will vary based upon market conditions at the time of issuance of the Notes and may be fixed or floating determined by reference to a base rate and spread.  From time to time, one or more of the Dealers and certain of their respective affiliates have provided, and may in the future provide, commercial banking, investment banking and other financial advisory services to us and our affiliates for which the Dealers have received or will receive customary fees and expenses. In addition, certain of the Dealers or their affiliates are lenders under the Credit Facility.  Revolving Credit Facility  In November 2017, we entered into a $2.0 billion unsecured revolving credit facility (Credit Facility) to be used for working capital and general corporate purposes, issuances of letters of credit and support for any 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 has a five -year term expiring 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. The Credit Facility replaced our previous $2.0 billion secured revolving credit facility (previous credit facility), which was terminated in connection with our entrance into the Credit Facility. Borrowings under our previous credit facility were secured with the lien of the Deed of Trust discussed in Note 7 below.  Borrowings under the Credit Facility bear interest at per annum rates equal to, at our option, (i) adjusted LIBOR plus a spread ranging from 0 .875% to 1.50% depending on credit ratings assigned to our senior secured non-credit enhanced long-term debt or (ii) an alternate base rate (the highest of (1) the prime rate of JPMorgan Chase, (2) the federal funds effective rate plus 0.50% , and (3) adjusted LIBOR plus 1.00% ) plus a spread ranging from 0.00% to 0.50% depending on credit ratings assigned to our senior secured non-credit enhanced long-term debt. Amounts borrowed under the Credit Facility, once repaid, can be borrowed again from time to time.  An unused commitment fee is payable quarterly in arrears and upon termination or commitment reduction at a rate equal to 0.075% to 0.225% (such spread depending on certain credit ratings assigned to our senior secured debt) of the daily unused commitments under the Credit Facility. Letter of credit fees on the stated amount of letters of credit issued under the Credit Facility are payable to the lenders quarterly in arrears and upon termination at a rate per annum equal to the spread over adjusted LIBOR. Customary fronting and administrative fees are also payable to letter of credit fronting banks. At December 31, 2018, letters of credit bore interest at 1.20% , and a commitment fee (at a rate of 0.125% per annum) was payable on the unfunded commitments under the Credit Facility, each based on our current credit ratings.  Under the terms of the Credit Facility, the commitments of the lenders to make loans to us are several and not joint. Accordingly, if any lender fails to make loans to us, our available liquidity could be reduced by an amount up to the aggregate amount of such lender’s commitments under the facility.  The Credit Facility contains customary covenants for facilities of this type, restricting, subject to certain exceptions, us and our subsidiaries from, among other things: incurring certain additional liens (not including liens relating to obligations secured pursuant to our Deed of Trust, which are permitted); entering into mergers and consolidations; sales of substantial assets and acquisitions and investments in subsidiaries. In addition, the Credit Facility requires that we maintain a consolidated senior debt-to-capitalization ratio of no greater than 0.65 to 1.00 and observe certain customary reporting requirements and other affirmative covenants. For purposes of the ratio, debt is calculated as indebtedness defined in the Credit Facility (principally, the sum of long-term debt, any capital leases, short-term debt and debt due currently in accordance with GAAP). Capitalization is calculated as membership interests determined in accordance with GAAP plus indebtedness described above. At December 31, 2018, we were in compliance with this and all other covenants .

Long-Term Debt

Long-Term Debt	12 Months Ended
	Dec. 31, 2018
Long-Term Debt [Abstract]
LONG-TERM DEBT	7. 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 December 31, 2018 and 2017, our long-term debt consisted of the following:   December 31,  2018 2017   Secured:  6.80% Fixed Senior Notes due September 1, 2018 $ - $ 550  2.15% Fixed Senior Notes due June 1, 2019 250 250  5.75% Fixed Senior Notes due September 30, 2020 126 126  4.10% Fixed Senior Notes due June 1, 2022 400 400  7.00% Fixed Debentures due September 1, 2022 482 800  2.95% Fixed Senior Notes due April 1, 2025 350 350  3.70% Fixed Senior Notes due November 15, 2028 350 -  5.75% Fixed Senior Notes due March 15, 2029 318 -  7.00% Fixed Senior Notes due May 1, 2032 500 500  7.25% Fixed Senior Notes due January 15, 2033 350 350  7.50% Fixed Senior Notes due September 1, 2038 300 300  5.25% Fixed Senior Notes due September 30, 2040 475 475  4.55% Fixed Senior Notes due December 1, 2041 400 400  5.30% Fixed Senior Notes due June 1, 2042 500 500  3.75% Fixed Senior Notes due April 1, 2045 550 550  3.80% Fixed Senior Notes due September 30, 2047 325 325  4.10% Fixed Senior Notes due November 15, 2048 450 -  Secured long-term debt 6,126 5,876  Unsecured:  Term loan credit agreement due no later than March 26, 2019 - 275  Term loan credit agreement maturing December 9, 2019 350 -  Total long-term debt 6,476 6,151  Unamortized discount and debt issuance costs (41) (34)  Less amount due currently (600) (550)  Long-term debt, less amounts due currently $ 5,835 $ 5,567  Debt-Related Activity in 2018  Debt Repayments  Repayments of long-term debt in 2018 consisted of $275 million aggregate principal amount of the term loan credit agreement due March 26, 2019 and $550 million aggregate principal amount of our 6.80% senior secured notes due September 1, 2018 (2018 Notes). The term loan credit agreement was repaid in full, and the 2018 Notes were defeased on August 10, 2018.  Debt Issuances  Senior Secured Notes  In August 2018, we issued $350 million aggregate principal amount of 3.70% senior secured notes due November 15, 2028 (the 2028 Notes) and $450 million aggregate principal amount of 4.10% senior secured notes due November 15, 2048 (the 2048 Notes and, together with the 2028 Notes, the New Notes). We used the proceeds (net of the initial purchasers’ discount, fees and expenses) of $791 million from the sale of the New Notes for general corporate purposes, including to pay the amount required for defeasance of our 2018 Notes, to repay the $131 million outstanding under our term loan credit agreement, and to repay notes due under our CP Program. The New Notes are secured by a first priority lien, and are secured equally and ratably with all of our other secured indebtedness.  Interest on the New Notes is payable in cash semiannually in arrears on May 15 and November 15 of each year, and the first interest payment was November 15, 2018. Prior to August 15, 2028, in the case of the 2028 Notes, and May 15, 2048, in the case of the 2048 Notes, we may redeem such Notes at any time, in whole or in part, at a price equal to 100% of their principal amount, plus accrued and unpaid interest and a “make-whole” premium. On and after August 15, 2028, in the case of the 2028 Notes, and May 15, 2048, in the case of the 2048 Notes, we may redeem such New Notes at any time, in whole or in part, at a redemption price equal to 100% of the principal amount of such New Notes, plus accrued and unpaid interest. The New Notes also contain customary events of default, including failure to pay principal or interest when due.  The New Notes and 2029 Notes (defined below) were issued in separate private placements. In January 2019, we completed an offering with the holders of the New Notes and 2029 Notes to exchange their respective New Notes and 2029 Notes for notes that have terms identical in all material respects to the New Notes and 2029 Notes (Exchange Notes), except that the Exchange Notes do not contain terms with respect to transfer restrictions, registration rights and payment of additional interest for failure to observe certain obligations in a certain registration rights agreement. The Exchange Notes were registered on a Form S-4, which was declared effective in December 2018.  Debt Exchange  On November 30, 2018, we issued $318 million aggregate principal amount of 5.75% Senior Secured Notes due 2029 (the “2029 Notes”) in exchange for a like principal amount of our outstanding 7.00% Debentures due 2022 (the “2022 Notes”). We received no proceeds from the exchange.  The 2029 Notes bear interest at a rate of 5.75% per annum and mature on March 15, 2029 . Interest on the 2029 Notes is payable in cash semiannually in arrears on March 15 and September 15 of each year, and the first interest payment is due on March 15, 2019. Prior to December 15, 2028, Oncor may redeem the New Notes at any time, in whole or in part, at a price equal to 100% of their principal amount, plus accrued and unpaid interest and a “make-whole” premium. On and after December 15, 2028, Oncor may redeem the New Notes at any time, in whole or in part, at a redemption price equal to 100% of the principal amount of such New Notes, plus accrued and unpaid interest. The 2029 Notes, the Indenture and the Deed of Trust also contain customary events of default, including failure to pay principal or interest on the New Notes when due, among others.  Term Loan Credit Agreement  On December 10, 2018, we entered into an unsecured term loan credit agreement in an aggregate principal amount of $350 million. We used the proceeds (net of the fees and expenses) for general corporate purposes, including to repay notes under our CP Program. The term loan credit agreement has a 12 -month term maturing on December 9, 2019 , and may be extended at our option up to an additional six months.  At December 31, 2018, we had outstanding borrowings of $350 million under the term loan credit agreement bearing interest at a rate per annum of 3.44% .  Loans under the term loan credit agreement bear interest at per annum rates equal to, at our option, (i) LIBOR plus 0.55% , until December 9, 2019, and LIBOR plus 0.60% on or after December 10, 2019, or (ii) an alternate base rate (the highest of (1) the prime rate of Mizuho, (2) the federal funds effective rate plus 0.50% , and (3) daily one-month LIBOR plus 1.00% ).  The term loan credit agreement contains customary covenants for facilities of this type, restricting, subject to certain exceptions, us and our subsidiaries from, among other things, incurring additional liens, entering into mergers and consolidations, and sales of substantial assets. In addition, the term loan credit agreement requires that we maintain a consolidated senior debt to capitalization ratio of no greater than 0.65 to 1.00 and observe certain customary reporting requirements and other affirmative covenants. At December 31, 2018, we were in compliance with the covenants under our term loan credit agreement.  The term loan credit agreement also contains customary events of default for facilities of this type the occurrence of which would allow the lenders to accelerate all outstanding loans and terminate their commitments, including certain changes in control of Oncor that are not permitted transactions under the term loan credit agreement, cross-default provisions in the event Oncor or any of its subsidiaries defaults on indebtedness in a principal amount in excess of $100 million or receives judgments for the payment of money in excess of $100 million that are not discharged within 60 days.  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 (excluding borrowings under the Credit Facility and the term loan credit agreement) with the lien of the Deed of Trust up to the aggregate of (i) the amount of available bond credits, and (ii) 85% of the lower of the fair value or cost of certain property additions that could be certified to the Deed of Trust collateral agent. At December 31, 2018, the amount of available bond credits was approximately $3.586 billion and the amount of future debt we could secure with property additions, subject to those property additions being certified to the Deed of Trust collateral agent, was $2.587 billion.  Maturities  Long-term debt maturities at December 31, 2018, are as follows:   Year Amount  2019 $ 600  2020 126  2021 -  2022 882  2023 -  Thereafter 4,868  Unamortized discount and debt issuance costs (41)  Total $ 6,435  Fair Value of Long-Term Debt  At December 31, 2018 and 2017, the estimated fair value of our long-term debt (including current maturities) totaled $7.086 billion and $7.153 billion, respectively, and the carrying amount totaled $6.435 billion and $6.117 billion, respectively. The fair value is estimated using observable market data, representing Level 2 valuations under accounting standards related to the determination of fair value.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies [Abstract]
COMMITMENTS AND CONTINGENCIES	8. COMMITMENTS AND CONTINGENCIES  EFH Bankruptcy Proceedings and Sempra Acquisition  In April 2014, EFH Corp. and the substantial majority of its direct and indirect subsidiaries at the time, including EFIH, EFCH and TCEH, commenced proceedings under Chapter 11 of the U.S. Bankruptcy Code. The Oncor Ring-Fenced Entities were not parties to the EFH Bankruptcy Proceedings. In connection with the plans of reorganization in the EFH Bankruptcy Proceedings, on March 9, 2018, the Sempra Acquisition was completed. See Note 2 for further information regarding the resolution of the EFH Bankruptcy Proceedings and the Sempra Acquisition and Note 11 for our related-party transactions involving members of the Texas Holdings Group and Sempra.  Leases  At December 31, 2018, our future minimum lease payments under our operating leases (with initial or remaining noncancelable lease terms in excess of one year) were as follows:    Year Amount  2019 $ 29  2020 22  2021 20  2022 15  2023 8  Thereafter 5  Total future minimum lease payments $ 99  Rent charged to operation and maintenance expense totaled $28 million, $27 million and $ 9 million for the years ended December 31, 2018, 2017 and 2016, respectively.  Capital Expenditures  As part of the Sempra Acquisition, Oncor has committed to make minimum aggregate capital expenditures equal to at least $7.5 billion over the 5-year period ending December 31, 2022 as discussed in Note 2.  Energy Efficiency Spending  We are required to annually invest in programs designed to improve customer electricity demand efficiencies to satisfy ongoing regulatory requirements. The 2019 requirement is $50 million, which is recoverable in rates.  Legal/Regulatory Proceedings  We are involved in various legal and administrative proceedings in the normal course of business, the ultimate resolution of which, in the opinion of management, should not have a material effect upon our financial position, results of operations or cash flows.  Labor Contracts  At December 31, 2018, approximately 18% of our full time employees were represented by a labor union and covered by a collective bargaining agreement with an expiration date of October 25, 2019 .  Environmental Contingencies  We must comply with environmental laws and regulations applicable to the handling and disposal of hazardous waste. We are in compliance with all current laws and regulations; however, the impact, if any, of changes to existing regulations or the implementation of new regulations is not determinable. The costs to comply with environmental regulations can be significantly affected by the following external events or conditions:  · changes to existing state or federal regulation by governmental authorities having jurisdiction over control of toxic substances and hazardous and solid wastes, and other environmental matters, and · the identification of additional sites requiring clean-up or the filing of other complaints in which we may be asserted to be a potential responsible party.  We have not identified any significant potential environmental liabilities at this time.

Membership Interests

Membership Interests	12 Months Ended
	Dec. 31, 2018
Membership Interests [Abstract]
MEMBERSHIP INTERESTS	9. MEMBERSHIP INTERESTS  Cash Distributions  Distributions are limited by the requirement to maintain our regulatory capital structure at or below the assumed debt-to-equity ratio established periodically by the PUCT for ratemaking purposes. The PUCT has the authority to determine what types of debt and equity are included in a utility’s debt-to-equity ratio. For purposes of this ratio, debt is calculated as long-term debt including capital leases plus unamortized gains on reacquired debt less unamortized issuance expenses, premiums and losses on reacquired debt. Equity is calculated as membership interests determined in accordance with GAAP, excluding the effects of acquisition accounting from a 2007 transaction (which included recording the initial goodwill and fair value adjustments and subsequent related impairments and amortization).  Our PUCT authorized capital structure is 57.5% debt to 42.5% equity effective November 27, 2017 based on the PUCT order issued in PUCT Docket No. 46957 (see Note 3 for additional information). Our previous PUCT authorized capital structure was 60% debt to 40% equity. At December 31, 2018, $41 million was available for distribution to our members, as our regulatory capitalization ratio was 57.3% debt to 42.7% equity. The PUCT order required us to record a regulatory liability from November 27, 2017 until the new authorized regulatory capital structure was met to reflect our actual capitalization prior to achieving the authorized capital structure. Our authorized regulatory capital structure was met in May 2018, and therefore we ceased accruing amounts to the capital structure refund regulatory liability as of that time. The regulatory liability of $6 million was approved on September 14, 2018 in PUCT Docket No. 48522, and the liability was subsequently returned to customers in September 2018.  On February 20, 2019, our board of directors declared a cash distribution of $71 million, which was paid to our members on February 22, 2019. During 2018, our board of directors declared, and we paid, the following cash distributions to our members:    Declaration Date Payment Date Amount  October 24, 2018 November 6, 2018 $ 179  July 25, 2018 August 1, 2018 $ 30  During 2017, our board of directors declared, and we paid, the following cash distributions to our members:    Declaration Date Payment Date Amount  July 26, 2017 August 1, 2017 $ 65  April 26, 2017 April 27, 2017 $ 86  March 22, 2017 March 24, 2017 $ 86  Cash Contributions   On February 19, 2019, we received cash capital contributions from our members totaling $70 million. During 2018, we received the following capital cash contributions from our members.    Received Amount  November 2018 $ 140  April 2018 $ 144  Accumulated Other Comprehensive Income (Loss)  The following table presents the changes to accumulated other comprehensive income (loss) for the years ended December 31, 2018, 2017 and 2016 net of tax.   Cash Flow Hedges – Interest Rate Swap Defined Benefit Pension and OPEB Plans Accumulated Other Comprehensive Income (Loss)   Balance at December 31, 2015 $ (22) $ (91) $ (113)  Defined benefit pension plans - - -  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2016 $ (20) $ (91) $ (111)  Defined benefit pension plans - 8 8  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2017 $ (18) $ (83) $ (101)  Defined benefit pension plans - (65) (65)  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2018 $ (16) $ (148) $ (164) 

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2018
Employee Benefit Plans [Abstract]
Employee Benefit Plans	10. EMPLOYEE BENEFIT PLANS  Regulatory Recovery of Pension and OPEB Costs  PURA provides for our recovery of pension and OPEB costs applicable to services of our active and retired employees, as well as services of certain EFH Corp./Vistra active and retired employees for periods prior to the deregulation and disaggregation of EFH Corp.’s electric utility businesses effective January 1, 2002 (recoverable service). Accordingly, in 2005, we entered into an agreement with a predecessor of EFH Corp. whereby we assumed responsibility for applicable pension and OPEB costs related to those personnel’s recoverable service. We subsequently entered into agreements with EFH Corp. and a Vistra affiliate regarding provision of these benefits. Pursuant to our agreement with the Vistra affiliate, we now sponsor an OPEB plan that provides certain retirement healthcare and life insurance benefits to eligible former Oncor, EFH Corp. and Vistra employees for whom both Oncor and Vistra bear a portion of the benefit responsibility. See “OPEB Plans” below for more information.  We are authorized to establish a regulatory asset or liability for the difference between the amounts of pension and OPEB costs approved in current billing rates and the actual amounts that would otherwise have been recorded as charges or credits to earnings related to recoverable service. Amounts deferred are ultimately subject to regulatory approval. At December 31, 2018 and 2017, we had recorded regulatory assets totaling $1.018 billion and $ 1.215 billion, respectively, related to pension and OPEB costs, including amounts related to deferred expenses as well as amounts related to unfunded liabilities that otherwise would be recorded as other comprehensive income.  We have also assumed primary responsibility for pension benefits of a closed group of retired and terminated vested plan participants not related to our regulated utility business (non-recoverable service) in a 2012 transaction. Any retirement costs associated with non-recoverable service is not recoverable through rates.  Pension Plans  We sponsor the Oncor Retirement Plan and also have liabilities under the Vistra Retirement Plan (formerly EFH Retirement Plan), both of which are qualified pension plans under Section 401(a) of the Code, and are subject to the provisions of ERISA. Employees do not contribute to either plan. These pension plans provide benefits to participants under one of two formulas: (i) a Cash Balance Formula under which participants earn monthly contribution credits based on their compensation and a combination of their age and years of service, plus monthly interest credits or (ii) a Traditional Retirement Plan Formula based on years of service and the average earnings of the three years of highest earnings. The interest component of the Cash Balance Formula is variable and is determined using the yield on 30-year Treasury bonds. Under the Cash Balance Formula, future increases in earnings will not apply to prior service costs.  All eligible employees hired after January 1, 2001 participate under the Cash Balance Formula. Certain employees, who, prior to January 1, 2002, participated under the Traditional Retirement Plan Formula, continue their participation under that formula. It is the sponsors’ policy to fund the plans on a current basis to the extent required under existing federal tax and ERISA regulations.  We also have the Supplemental Retirement Plan for certain employees whose retirement benefits cannot be fully earned under the qualified retirement plan. Supplemental Retirement Plan amounts are included in the reported pension amounts below.  At December 31, 2018, the pension plans’ projected benefit obligation included a net actuarial gain of $232 million for 2018 due primarily to an increase in the discount rate. Actual returns on pension plan assets in 2018 were less than the expected return on assets by $299 million resulting in a net actuarial loss of $67 million. We expect the pension plans’ estimated amortizations of net actuarial losses to decrease by $20 million in 2019 reflecting these changes.  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. The establishment of the second plan is not expected to have an impact on our financial statements.  OPEB plans’ contributions are generally required to be made at least annually based on OPEB expense included in rates. Contributions are placed in an irrevocable external trust fund dedicated to the payment of OPEB expenses.  At December 31, 2018, the OPEB plans’ projected benefit obligation included a net actuarial gain of $196 million for 2018 including $88 million from an increase in the discount rate and $108 million from changes associated with updates to census data, mortality, health care claims and trend assumptions. Actual returns on OPEB plans’ assets in 2018 were less than the expected return on assets by $19 million resulting in a net actuarial gain of $177 million. We expect the OPEB plans’ estimated amortizations of net actuarial losses to decrease by $38 million in 2019 reflecting these changes.  Pension and OPEB Costs Recognized as Expense  Pension and OPEB amounts provided herein include amounts related only to our portion of the various plans based on actuarial computations and reflect our employee and retiree demographics as described above. Our net costs related to pension and OPEB plans for the years ended December 31, 2018, 2017 and 2016 were comprised of the following:      Year Ended December 31,  2018 2017 2016   Pension costs $ 77 $ 85 $ 76  OPEB costs 70 58 62  Total benefit costs 147 143 138  Less amounts recognized principally as property or a regulatory asset (69) (98) (100)  Net amounts recognized as operation and maintenance expense or other deductions $ 78 $ 45 $ 38  The calculated value method is used to determine the market-related value of the assets held in the trust for purposes of calculating our pension costs. Realized and unrealized gains or losses in the market-related value of assets are included over a rolling four -year period. Each year, 25% of such gains and losses for the current year and for each of the preceding three years is included in the market-related value. Each year, the market-related value of assets is increased for contributions to the plan and investment income and is decreased for benefit payments and expenses for that year.  The fair value method is used to determine the market-related value of the assets held in the trust for purposes of calculating OPEB cost. Detailed Information Regarding Pension and OPEB Benefits  The following pension and OPEB information is based on December 31, 2018, 2017 and 2016 measurement dates:     Pension Plans OPEB Plans  Year Ended December 31, Year Ended December 31,  2018 2017 2016 2018 2017 2016   Assumptions Used to Determine Net Periodic Pension and OPEB Costs:  Discount rate 3.54% 4.05% 4.30% 3.73% 4.35% 4.60%  Expected return on plan assets 5.11% 5.17% 5.54% 6.20% 6.10% 6.30%  Rate of compensation increase 4.46% 3.33% 3.29% - - -   Components of Net Pension and OPEB Costs:  Service cost $ 27 $ 24 $ 23 $ 8 $ 7 $ 7  Interest cost 121 131 134 44 47 49  Expected return on assets (120) (115) (122) (9) (8) (9)  Amortization of prior service cost (credit) - - - (30) (20) (20)  Amortization of net loss 49 45 41 57 32 35  Net periodic pension and OPEB costs $ 77 $ 85 $ 76 $ 70 $ 58 $ 62   Other Changes in Plan Assets and Benefit Obligations Recognized as Regulatory Assets or in Other Comprehensive Income:  Net loss (gain) $ 67 $ (11) $ 41 $ (177) $ 139 $ 10  Amortization of net loss (49) (45) (41) (57) (32) (35)  Plan amendments - - - - (78) -  Amortization of prior service (cost) credit - - - 30 20 20  Total recognized as regulatory assets or other comprehensive income 18 (56) - (204) 49 (5)  Total recognized in net periodic pension and OPEB costs and as regulatory assets or other comprehensive income $ 95 $ 29 $ 76 $ (134) $ 107 $ 57      Pension Plans OPEB Plans  Year Ended December 31, Year Ended December 31,  2018 2017 2016 2018 2017 2016   Assumptions Used to Determine Benefit Obligations at Period End:  Discount rate 4.18% 3.54% 4.05% 4.41% 3.73% 4.35%  Rate of compensation increase 4.53% 4.46% 3.33% - - -      Pension Plans OPEB Plans  Year Ended December 31, Year Ended December 31,  2018 2017 2018 2017   Change in Projected Benefit Obligation:  Projected benefit obligation at beginning of year $ 3,500 $ 3,307 $ 1,198 $ 1,116  Service cost 27 24 8 7  Interest cost 121 131 44 47  Participant contributions - - 19 19  Plan amendments - - - (78)  Actuarial (gain) loss (232) 201 (196) 154  Benefits paid (175) (163) (67) (67)  Annuity purchase (79) - - -  Projected benefit obligation at end of year $ 3,162 $ 3,500 $ 1,006 $ 1,198  Accumulated benefit obligation at end of year $ 3,069 $ 3,387 $ - $ -   Change in Plan Assets:  Fair value of assets at beginning of year $ 2,600 $ 2,287 $ 149 $ 143  Actual return (loss) on assets (179) 327 (10) 23  Employer contributions 82 149 41 31  Participant contributions - - 19 19  Benefits paid (175) (163) (67) (67)  Annuity purchase (79) - - -  Fair value of assets at end of year $ 2,249 $ 2,600 $ 132 $ 149   Funded Status:  Projected benefit obligation at end of year $ (3,162) $ (3,500) $ (1,006) $ (1,198)  Fair value of assets at end of year 2,249 2,600 132 149  Funded status at end of year $ (913) $ (900) $ (874) $ (1,049)          Pension Plans OPEB Plans  Year Ended December 31, Year Ended December 31,  2018 2017 2018 2017   Amounts Recognized in the Balance Sheet Consist of:  Liabilities:  Other current liabilities $ (4) $ (4) $ (7) $ (12)  Other noncurrent liabilities (909) (896) (867) (1,037)  Net liability recognized $ (913) $ (900) $ (874) $ (1,049)  Regulatory assets:  Net loss $ 534 $ 538 $ 171 $ 402  Prior service cost (credit) - - (57) (86)  Net regulatory asset recognized $ 534 $ 538 $ 114 $ 316  Accumulated other comprehensive net loss $ 147 $ 124 $ 1 $ 3  The following tables provide information regarding the assumed health care cost trend rates.   Year Ended December 31,  2018 2017   Assumed Health Care Cost Trend Rates – Not Medicare Eligible:  Health care cost trend rate assumed for next year 7.60% 8.00%  Rate to which the cost trend is expected to decline (the ultimate trend rate) 4.50% 4.50%  Year that the rate reaches the ultimate trend rate 2026 2026   Assumed Health Care Cost Trend Rates – Medicare Eligible:  Health care cost trend rate assumed for next year 8.70% 9.40%  Rate to which the cost trend is expected to decline (the ultimate trend rate) 4.50% 4.50%  Year that the rate reaches the ultimate trend rate 2027 2026   1-Percentage Point Increase 1-Percentage Point Decrease   Sensitivity Analysis of Assumed Health Care Cost Trend Rates:  Effect on accumulated postretirement obligation $ 124 $ (103)  Effect on postretirement benefits cost 7 (5)  The following table provides information regarding pension plans with projected benefit obligations (PBO) and accumulated benefit obligations (ABO) in excess of the fair value of plan assets.    At December 31,  2018 2017   Pension Plans with PBO and ABO in Excess of Plan Assets:  Projected benefit obligations $ 3,162 $ 3,316  Accumulated benefit obligations 3,069 3,207  Plan assets 2,249 2,409  Pension and OPEB Plans Investment Strategy and Asset Allocations  Our investment objective for the retirement plans is to invest in a suitable mix of assets to meet the future benefit obligations at an acceptable level of risk, while minimizing the volatility of contributions. Equity securities are held to achieve returns in excess of passive indexes by participating in a wide range of investment opportunities. International equity, real estate securities and credit strategies (high yield bonds, emerging market debt and bank loans) are used to further diversify the equity portfolio. International equity securities may include investments in both developed and emerging international markets. Fixed income securities include primarily corporate bonds from a diversified range of companies, U.S. Treasuries and agency securities and money market instruments. Our investment strategy for fixed income investments is to maintain a high grade portfolio of securities, which assists us in managing the volatility and magnitude of plan contributions and expense while maintaining sufficient cash and short-term investments to pay near-term benefits and expenses. The Oncor Retirement Plan’s investments are managed in two pools: one pool associated with the recoverable service portion of plan obligations related to Oncor’s regulated utility business, and a second pool associated with the non-recoverable service portion of plan obligations not related to Oncor’s regulated utility business. Each pool is invested in a broadly diversified portfolio as shown below. The second pool represents 28% of total investments at December 31, 2018.  The target asset allocation ranges of the pension plan’s investments by asset category are as follows:   Target Allocation Ranges  Asset Category Recoverable Non-recoverable   International equities 13% - 21% 6% - 12%  U.S. equities 16% - 24% 8% - 14%  Real estate 3% - 7% -  Credit strategies 5% - 10% 5% - 9%  Fixed income 45% - 55% 68% - 78%  Our investment objective for the OPEB plans primarily follows the objectives of the pension plans discussed above, while maintaining sufficient cash and short-term investments to pay near-term benefits and expenses. The actual amounts at December 31, 2018 provided below are consistent with the asset allocation targets.  Fair Value Measurement of Pension Plans’ Assets  At December 31, 2018 and 2017, pension plans’ assets measured at fair value on a recurring basis consisted of the following:   At December 31, 2018  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ - $ - $ - $ -  Equity securities:  U.S. 170 2 - 172  International 239 - - 239  Fixed income securities:  Corporate bonds (a) - 930 - 930  U.S. Treasuries - 110 - 110  Other (b) - 69 - 69  Real estate - - 3 3  Total assets in the fair value hierarchy $ 409 $ 1,111 $ 3 1,523  Total assets measured at net asset value (c) 726  Total fair value of plan assets $ 2,249   At December 31, 2017  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ - $ 11 $ - $ 11  Equity securities:  U.S. 235 2 - 237  International 271 - - 271  Fixed income securities:  Corporate bonds (a) - 1,081 - 1,081  U.S. Treasuries - 251 - 251  Other (b) - 44 - 44  Real estate - - 3 3  Total assets in the fair value hierarchy $ 506 $ 1,389 $ 3 1,898  Total assets measured at net asset value (c) 702  Total fair value of plan assets $ 2,600 _____________ (a) Substantially all corporate bonds are rated investment grade by a major ratings agency such as Moody’s. (b) Other consists primarily of municipal bonds, emerging market debt, bank loans and fixed income derivative instruments. (c) Fair value was measured using the net asset value (NAV) per share as a practical expedient as the investments did not have a readily determinable fair value and are not required to be classified in the fair value hierarchy. The NAV fair value amounts presented here are intended to permit a reconciliation to the total fair value of plan assets.    Fair Value Measurement of OPEB Plans’ Assets  At December 31, 2018 and 2017, OPEB plans’ assets measured at fair value on a recurring basis consisted of the following:   At December 31, 2018  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ 15 $ - $ - $ 15  Equity securities:  U.S. 21 - - 21  International 22 - - 22  Fixed income securities:  Corporate bonds (a) - 26 - 26  U.S. Treasuries - 3 - 3  Other (b) 28 1 - 29  Total assets in the fair value hierarchy $ 86 $ 30 $ - 116  Total assets measured at net asset value (c) 16  Total fair value of plan assets $ 132   At December 31, 2017  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ 1 $ 1 $ - $ 2  Equity securities:  U.S. 35 - - 35  International 33 - - 33  Fixed income securities:  Corporate bonds (a) - 30 - 30  U.S. Treasuries - 3 - 3  Other (b) 28 1 - 29  Total assets in the fair value hierarchy $ 97 $ 35 $ - 132  Total assets measured at net asset value (c) 17  Total fair value of plan assets $ 149 _____________ (a) Substantially all corporate bonds are rated investment grade by a major ratings agency such as Moody’s. (b) Other consists primarily of diversified bond mutual funds. (c) Fair value was measured using the net asset value (NAV) per share as a practical expedient as the investments did not have a readily determinable fair value and are not required to be classified in the fair value hierarchy. The NAV fair value amounts presented here are intended to permit a reconciliation to the total fair value of plan assets.  Expected Long-Term Rate of Return on Assets Assumption  The retirement plans’ strategic asset allocation is determined in conjunction with the plans’ advisors and utilizes a comprehensive Asset-Liability modeling approach to evaluate potential long-term outcomes of various investment strategies. The modeling incorporates long-term rate of return assumptions for each asset class based on historical and future expected asset class returns, current market conditions, rate of inflation, current prospects for economic growth, and taking into account the diversification benefits of investing in multiple asset classes and potential benefits of employing active investment management.    Pension Plans OPEB Plans  Asset Class Expected Long-Term Rate of Return Asset Class Expected Long-Term Rate of Return   International equity securities 7.70% 401(h) accounts 6.63%  U.S. equity securities 6.60% Life insurance VEBA 6.08%  Real estate 5.40% Union VEBA 6.08%  Credit strategies 5.58% Non-union VEBA 2.90%  Fixed income securities 4.30% Weighted average 6.19%  Weighted average (a) 5.64% _____________ (a) The 2019 expected long-term rate of return for the nonregulated portion of the Oncor Retirement Plan is 4.91%, and for Oncor's portion of the Vistra Retirement Plan is 5.29% .  Significant Concentrations of Risk  The plans’ investments are exposed to risks such as interest rate, capital market and credit risks. We seek to optimize return on investment consistent with levels of liquidity and investment risk which are prudent and reasonable, given prevailing capital market conditions and other factors specific to participating employers. While we recognize the importance of return, investments will be diversified in order to minimize the risk of large losses unless, under the circumstances, it is clearly prudent not to do so. There are also various restrictions and guidelines in place including limitations on types of investments allowed and portfolio weightings for certain investment securities to assist in the mitigation of the risk of large losses.  Assumed Discount Rate  For the Oncor retirement plans at December 31, 2018, we selected the assumed discount rate using the Aon AA-AAA Bond Universe yield curve, which is based on corporate bond yields and at December 31, 2018 consisted of 1,044 corporate bonds with an average rating of AA and AAA using Moody’s, S&P and Fitch ratings. For the Oncor OPEB Plans at December 31, 2018, we selected the assumed discount rate using the Aon AA Above Median yield curve, which is based on corporate bond yields and at December 31, 2018 consisted of 377 corporate bonds with an average rating of AA using Moody’s, S&P and Fitch ratings.  Amortization in 2019  In 2019, amortization of the net actuarial loss for the defined benefit pension plans from regulatory assets and other comprehensive income into net periodic benefit cost is expected to be $26 million and $3 million, respectively. No amortization of prior service credit is expected in 2019 for the defined benefit pension plans. Amortization of the net actuarial loss for the OPEB plans from regulatory assets and other comprehensive income into net periodic benefit cost is expected to be $19 million and zero , respectively. Amortization of prior service credit for the OPEB plans from regulatory assets and other comprehensive income into net periodic benefit cost is expected to be $19 million and zero , respectively.  Pension and OPEB Plans Cash Contributions  Our contributions to the benefit plans were as follows:   Year Ended December 31,  2018 2017 2016   Pension plans contributions $ 82 $ 149 $ 4  OPEB plans contributions 41 31 31  Total contributions $ 123 $ 180 $ 35  Our funding for the pension plans and the Oncor OPEB Plans is expected to total $41 million and $35 million, respectively in 2019 and approximately $538 million and $179 million, respectively, in the 2019 to 2023 period.  Future Benefit Payments  Estimated future benefit payments to participants are as follows:   2019 2020 2021 2022 2023 2024-28   Pension plans $ 183 $ 187 $ 192 $ 196 $ 200 $ 1,031  OPEB plans $ 53 $ 56 $ 58 $ 61 $ 63 $ 320  Thrift Plan  Our employees are eligible to participate in a qualified savings plan, a participant-directed defined contribution plan intended to qualify under Section 401(a) of the Code, and is subject to the provisions of ERISA. Under the plan, employees may contribute, through pre-tax salary deferrals and/or after-tax applicable payroll deductions, a portion of their regular salary or wages as permitted under law. Employer matching contributions are made in an amount equal to 100% of the first 6% of employee contributions for employees who are covered under the Cash Balance Formula of the Oncor Retirement Plan, and 75% of the first 6% of employee contributions for employees who are covered under the Traditional Retirement Plan Formula of the Oncor Retirement Plan. Employer matching contributions are made in cash and may be allocated by participants to any of the plan's investment options. Our contributions to the Oncor Thrift Plan totaled $19 million, $17 million and $15 million for the years ended December 31, 2018, 2017 and 2016, respectively.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2018
Stock-Based Compensation [Abstract]
STOCK-BASED COMPENSATION	11. STOCK-BASED COMPENSATION  We currently do not offer stock-based compensation to our employees or directors. In 2008, we established the SARs Plan under which certain of our executive officers and key employees were granted stock appreciation rights payable in cash, or in some circumstances, Oncor membership interests. In February 2009, we established the Oncor Electric Delivery Company LLC Director Stock Appreciation Rights Plan (the Director SARs Plan) under which certain non-employee members of our board of directors and other persons having a relationship with us were granted SARs payable in cash, or in some circumstances, Oncor membership interests.  In November 2012, we accepted the early exercise of all outstanding SARs (both vested and unvested) issued to date pursuant to both SARs Plans. As part of the 2012 early exercise of SARs we began accruing interest on dividends declared with respect to the SARs. Under both SARs plans, dividends that were paid in respect of Oncor membership interests while the SARs were outstanding were credited to the SARs holder’s account as if the SARs were units, payable upon the earliest to occur of death, disability, separation from service, unforeseeable emergency, a change in control, or the occurrence of an event triggering SAR exercisability pursuant to Section 5(c)(ii) of the SARs Plan . As a result of the Sempra Acquisition, the dividend and interest accounts were distributed in 2018, totaling $15 million. For accounting purposes, the liability was discounted based on an employee’s or director’s expected retirement date . We recognized $4 million, $1 million and $1 million in accretion and interest with respect to such dividend and interest accounts in the years 2018, 2017 and 2016, respectively. 

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2018
Related-Party Transactions [Abstract]
RELATED-PARTY TRANSACTIONS	12. RELATED-PARTY TRANSACTIONS  The following represent our significant related-party transactions and related matters. As a result of the EFH Bankruptcy Proceedings, EFH Corp. subsidiaries discontinued providing us administrative services after 2016. As a result of the Vistra Spin-Off, Vistra and its subsidiaries, including Luminant and TXU Energy, ceased to be related parties as of October 3, 2016.  · We recorded revenue from TCEH, principally for electricity delivery fees, which totaled $715 million for the period January 1, 2016 through October 2, 2016. The fees are based on rates regulated by the PUCT that apply to all REPs.    · EFH Corp. subsidiaries charged us for certain administrative services at cost in 2016. Our payments to EFH Corp. subsidiaries for administrative services, which are primarily reported in operation and maintenance expenses, totaled $1 million for 2016. We also charged each other for shared facilities at cost. Our payments to EFH Corp. subsidiaries for shared facilities totaled $3 million for 2016. Payments we received from EFH Corp. subsidiaries related to shared facilities totaled $1 million for 2016.  · 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 which 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 under “Provision in Lieu of Income Taxes.” Under the “in lieu of” tax concept, all in lieu of tax assets and tax liabilities represent amounts that will eventually be settled with our members. In the event such amounts are not paid under the tax sharing agreement, it is probable that this regulatory liability will continue to be included in Oncor’s rate setting processes.  Amounts payable to (receivable from) members related to income taxes under the agreement and reported on our balance sheet consisted of the following:    At December 31, 2018 At December 31, 2017  STH Texas Transmission Total EFH Corp. Texas Transmission Total   Federal income taxes payable (receivable) $ 4 $ 1 $ 5 $ (21) $ (5) $ (26)  Texas margin taxes payable 21 - 21 21 - 21  Net payable (receivable) $ 25 $ 1 $ 26 $ - $ (5) $ (5)  Cash payments made to (received from) members related to income taxes consisted of the following:   Year Ended December 31, 2018 Year Ended December 31, 2017 Year Ended December 31, 2016  STH EFH Corp. Texas Transm. Total EFH Corp. Texas Transm. Total EFH Corp.   Federal income taxes $ 59 $ (19) $ 10 $ 50 $ (102) $ (12) $ (114) $ -  Texas margin taxes 21 - - 21 20 - 20 20  Total payments (receipts) $ 80 $ (19) $ 10 $ 71 $ (82) $ (12) $ (94) $ 20  · As of March 8, 2018, approximately 16% of the equity in an existing vendor of the company was owned by a member of the Sponsor Group. As a result of the Sempra Acquisition, the Sponsor Group ceased to be a related party as of March 9, 2018. During 2018, 2017 and 2016, this vendor performed transmission and distribution system construction and maintenance services for us. Cash payments were made for such services to this vendor and/or its subsidiaries totaling $35 million dollars for the year-to-date period ended March 8, 2018, of which approximately $33 million was capitalized and $2 million was recorded as an operation and maintenance expense. Cash payments were made for such services to this vendor and/or its subsidiaries totaling $219 million for 2017, of which approximately $210 million was capitalized and $9 million recorded as an operation and maintenance expense, and $188 million for 2016, of which approximately $180 million was capitalized and $8 million recorded as an operation and maintenance expense. At December 31, 2017, we had outstanding trade payables to this vendor of $7 million.  See Notes 1, 5, 9 and 10 for information regarding the tax sharing agreement, distributions to members and our participation in the Vistra Retirement Plan.

Supplementary Financial Informa

Supplementary Financial Information	12 Months Ended
	Dec. 31, 2018
Supplementary Financial Information [Abstract]
SUPPLEMENTARY FINANCIAL INFORMATION	13. SUPPLEMENTARY FINANCIAL INFORMATION  Variable Interest Entities  Through December 29, 2016, we were the primary beneficiary of and consolidated a former wholly-owned VIE, Bondco, which was organized for the limited purpose of issuing specific transition bonds and purchasing and owning transition property acquired from us that was pledged as collateral to secure the bonds. We acted as the servicer for this entity to collect transition charges authorized by the PUCT. These funds were remitted to the trustee and used for interest and principal payments on the transition bonds and related costs. Bondco was dissolved effective December 29, 2016.  Bondco had issued an aggregate $1.3 billion principal amount of transition bonds during 2003 and 2004. The 2003 Series transition bonds matured and were paid in full in 2015 and the 2004 Series transition bonds matured and were paid in full in May 2016. We did not provide any financial support to Bondco during the year ended December 31, 2016.  Other Income and (Deductions)   Year Ended December 31,  2018 2017 2016   Professional fees $ (12) $ (15) $ (15)  Sempra Acquisition related costs (12) - -  Recoverable Pension and OPEB - non-service costs (a) (53) (31) (28)  Non-recoverable pension and OPEB (Note 10) (6) (5) (2)  Interest income 1 6 2  Other (2) (1) -  Total other income and (deductions) - net $ (84) $ (46) $ (43) ________________ (a) Years 2017 and 2016 are adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.  Interest Expense and Related Charges   Year Ended December 31,  2018 2017 2016   Interest $ 358 $ 351 $ 341  Amortization of debt issuance costs and discounts 6 3 3  Less allowance for funds used during construction – capitalized interest portion (13) (12) (8)  Total interest expense and related charges $ 351 $ 342 $ 336  Trade Accounts and Other Receivables  Trade accounts and other receivables reported on our balance sheet consisted of the following:   At December 31,  2018 2017   Gross trade accounts and other receivables $ 562 $ 638  Allowance for uncollectible accounts (3) (3)  Trade accounts receivable – net $ 559 $ 635  At December 31, 2018, REP subsidiaries of two of our largest counterparties represented approximately 13% and 10% of the trade accounts receivable balance and at December 31, 2017, represented approximately 12% and 10% of the trade accounts receivable balance.  Under a PUCT rule relating to the Certification of Retail Electric Providers, write-offs of uncollectible amounts owed by nonaffiliated REPs are deferred as a regulatory asset.  Investments and Other Property  Investments and other property reported on our balance sheet consist of the following:   At December 31,  2018 2017   Assets related to employee benefit plans, including employee savings programs $ 108 $ 111  Land 12 2  Total investments and other property $ 120 $ 113  The majority of these assets represent cash surrender values of life insurance policies that are purchased to fund liabilities under deferred compensation plans. At December 31, 2018 and 2017, the face amount of these policies totaled $157 million and $162 million, respectively, and the net cash surrender values (determined using a Level 2 valuation technique) totaled $87 million and $84 million at December 31, 2018 and 2017, respectively. Changes in cash surrender value are netted against premiums paid. Other investment assets held to satisfy deferred compensation liabilities are recorded at market value.  Property, Plant and Equipment  Property, plant and equipment reported on our balance sheet consisted of the following:    Composite Depreciation Rate/ At December 31,  Avg. Life at December 31, 2018 2018 2017  Assets in service:  Distribution 2.8% / 35.1 years $ 13,105 $ 12,467  Transmission 2.9% / 34.4 years 8,568 7,870  Other assets 6.9% / 14.6 years 1,497 1,380  Total 23,170 21,717  Less accumulated depreciation 7,513 7,255  Net of accumulated depreciation 15,657 14,462  Construction work in progress 417 402  Held for future use 16 15  Property, plant and equipment – net $ 16,090 $ 14,879  Depreciation expense as a percent of average depreciable property approximated 2.8% , 3.4% and 3.5% for the years ended December 31, 2018, 2017 and 2016, respectively.  Intangible Assets  Intangible assets (other than goodwill) reported on our balance sheet as part of property, plant and equipment consisted of the following:   At December 31, 2018 At December 31, 2017  Gross Gross  Carrying Accumulated Carrying Accumulated  Amount Amortization Net Amount Amortization Net  Identifiable intangible assets subject to amortization:  Land easements $ 464 $ 101 $ 363 $ 453 $ 96 $ 357  Capitalized software 787 385 402 679 339 340  Total $ 1,251 $ 486 $ 765 $ 1,132 $ 435 $ 697  A ggregate amortization expense for intangible assets totaled $50 million, $57 million and $61 million for the years ended December 31, 2018, 2017 and 2016, respectively. At December 31, 2018, the weighted average remaining useful lives of capitalized land easements and software were 82 years and 9 years, respectively. The estimated aggregate amortization expense for each of the next five fiscal years is as follows:   Year Amortization Expense   2019 $ 50  2020 49  2021 49  2022 49  2023 49  At both December 31, 2018 and 2017, goodwill totaling $ 4.1 billion was reported on our balance sheet. None of this goodwill is being deducted for tax purposes. See Note 1 regarding goodwill impairment assessment and testing.  Employee Benefit Obligations and Other  Employee benefit obligations and other reported on our balance sheet consisted of the following:   At December 31,  2018 2017   Retirement plans and other employee benefits $ 1,858 $ 2,035  Investment tax credits 8 10  Other 77 57  Total employee benefit obligations and other $ 1,943 $ 2,102  Supplemental Cash Flow Information   Year Ended December 31,  2018 2017 2016  Cash payments related to:   Interest $ 368 $ 345 $ 336  Less capitalized interest (13) (12) (8)  Interest payments (net of amounts capitalized) $ 355 $ 333 $ 328   Amount in lieu of income taxes:  Federal $ 50 $ (114) $ -  State 21 20 20  Total payments (refunds) in lieu of income taxes $ 71 $ (94) $ 20   Noncash Sharyland Asset Exchange costs $ - $ 383 $ -  Noncash construction expenditures (a) $ 174 $ 129 $ 122 ______________ (a) Represents end-of-period accruals.  Quarterly Information (unaudited)  Results of operations by quarter for the years ended December 31, 2018 and 2017 are summarized below. In our opinion, all adjustments (consisting of normal recurring accruals) necessary for a fair statement of such amounts have been made. Quarterly results are not necessarily indicative of a full year’s operations because of seasonal and other factors.   2018 First Quarter Second Quarter Third Quarter Fourth Quarter  Operating revenues $ 990 $ 1,021 $ 1,095 $ 995  Operating income 202 244 293 206  Net income 89 143 194 119   2017 First Quarter Second Quarter Third Quarter Fourth Quarter  Operating revenues $ 935 $ 964 $ 1,068 $ 991  Operating income (1) 164 202 252 190  Net income 73 112 157 77 

Acquisition Activity

Acquisition Activity	12 Months Ended
	Dec. 31, 2018
Acquisition Activity [Abstract]
Acquisition Activity	14. ACQUISITION ACTIVITY  Pending InfraREIT Acquisition  On October 18, 2018, we entered into the InfraREIT Merger Agreement, pursuant to which we plan to acquire all of the equity interests of InfraREIT and its subsidiary, InfraREIT Partners, subject to the conditions discussed below. The InfraREIT Acquisition will occur 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. InfraREIT’s stockholders and the limited partners of InfraREIT Partners will receive $21.00 in cash per share of common stock or limited partnership unit, as applicable. Total purchase price based on the number of shares and partnership units of InfraREIT and InfraREIT Partners currently outstanding is approximately $1.275 billion, plus we will bear certain transaction costs incurred by InfraREIT (including a management agreement termination fee of approximately $40.5 million that InfraREIT has agreed to pay Hunt Consolidated, Inc. at closing). The acquisition also includes InfraREIT’s outstanding debt, which totaled approximately $945 million at September 30, 2018.  In connection with entering into the InfraREIT Merger Agreement, we have received a commitment letter from Sempra and certain indirect equity holders of Texas Transmission (collectively, Equity Commitment Parties), pursuant to which, subject to the terms and conditions set forth therein, the Equity Commitment Parties have committed to provide their pro rata share of capital contributions to us in an aggregate principal amount of up to $1.330 billion, to fund the cash consideration payable by us in the InfraREIT Acquisition and the payment of related fees and expenses. The funding provided for in the commitment letter is contingent on the satisfaction of customary conditions, including the substantially simultaneous closing of the transactions contemplated by the InfraREIT Merger Agreement, but is not a condition to the closing of the InfraREIT Acquisition.  As a condition to the InfraREIT Acquisition, InfraREIT’s subsidiary, SDTS, and SDTS’s tenant, SU, will complete an asset exchange (SDTS-SU Asset Exchange) immediately prior to the closing of the InfraREIT Acquisition, pursuant to which SDTS will exchange certain of its south Texas assets for certain north Texas assets owned by SU. As a result, upon closing of the InfraREIT Acquisition, we will own all of SDTS’s and SU’s assets and projects in north, central and west Texas and SU will own its and SDTS’s assets in south Texas. In addition, as a condition to the closing of the SDTS-SU Asset Exchange, Sempra will acquire an indirect 50 percent limited partnership interest in SU (Sempra-SU Transaction). As a result of the Sempra-SU Transaction, SU will be our affiliate for purposes of PUCT rules. The SDTS-SU Asset Exchange also contemplates that at closing we and SU will enter into a future development agreement and, subject to receipt of certain PUCT approvals, an operation and maintenance agreement. The future development agreement addresses ownership and funding of potential future SU transmission projects, under certain circumstances, where at least one endpoint of the project is a legacy SDTS asset. Oncor and SU will each own and fund certain percentages of the project depending on the project type and location of the transmission project’s endpoints. The operation and maintenance agreement provides that we will provide to SU certain operations and maintenance services with respect to the SU assets in south Texas. Such services will be provided by us to SU at cost without a markup or profit.  Oncor, InfraREIT and InfraREIT Partners have agreed to use their respective reasonable best efforts, subject to certain exceptions, to consummate the InfraREIT Acquisition as promptly as practicable. Closing of the InfraREIT Acquisition is subject to the satisfaction of customary closing conditions, including the satisfaction of certain regulatory conditions, including the receipt of the approval of the PUCT and the FERC, and clearance by the Committee on Foreign Investment in the United States. The parties filed a single, integrated Joint Application for Sale, Transfer or Merger with the PUCT on November 30, 2018 in PUCT Docket No. 48929. The parties also filed a single, integrated Joint Application under Section 203 of the Federal Power Act on November 30, 2018, in Docket No. EC19-31. On February 7, 2019, InfraREIT announced that its stockholders voted to adopt the InfraREIT Merger Agreement at a special meeting of its stockholders.  Sharyland Asset Exchange  On July 21, 2017, we entered into an Agreement and Plan of Merger by and among the Sharyland Entities, Oncor, and Oncor AssetCo LLC, a Texas limited liability company and wholly-owned subsidiary of Oncor. Pursuant to that agreement, on November 9, 2017, we exchanged approximately $383 million of our transmission assets, consisting of 517 circuit miles of 345 kV transmission lines, and approximately $25 million in cash for approximately $408 million of the Sharyland Entities’ distribution assets (constituting substantially all of their electricity distribution business) and certain of their transmission assets. The Sharyland Asset Exchange expanded our customer base in west Texas and provides some potential growth opportunities of the distribution network. The transaction for assets between Oncor and the Sharyland Entities was structured to qualify, in part, as a simultaneous tax deferred like kind exchange of assets to the extent that the assets exchanged are of “like kind” (within the meaning of section 1031 of the Code). The Sharyland Asset Exchange did not have a material effect on our results of operations, financial position or cash flows.      

Description Of Business and S_2

Description Of Business and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Description Of Business and Significant Accounting Policies [Abstract]
Description Of Business	Description of Business  References in this report to “we,” “our,” “us” and “the company” are to Oncor and/or its subsidiaries as apparent in the context. See “Glossary” for definition of terms and abbreviations.  We are a regulated electricity transmission and distribution company principally engaged in providing delivery services to REPs that sell power in the north-central, eastern and western parts of Texas. 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 2016 consolidated financial statements include our former wholly-owned, bankruptcy-remote financing subsidiary, Bondco, a VIE through December 29, 2016, at which time it was dissolved (see Note 13) . This financing subsidiary was organized for the limited purpose of issuing certain transition bonds to recover generation-related regulatory asset stranded costs and other qualified costs under an order issued by the PUCT in 2002. Bondco issued an aggregate $1.3 billion principal amount of transition bonds during 2003 and 2004. The 2003 Series transition bonds matured and were paid in full in 2015 and the 2004 Series transition bonds matured and were paid in full in May 2016. Final true-up proceedings and refunds of over-collected transition charges for the transition bonds were conducted by Oncor and the PUCT during 2016 and had no material net income impact.  Various “ring-fencing” measures have been taken to enhance 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. For more information on the ring-fencing measures, see Note 2.
EFH Bankruptcy Proceedings And Change In Indirect Ownership Of Oncor	EFH Bankruptcy Proceedings and Sempra Acquisition  In April 2014, EFH Corp. and the substantial majority of its direct and indirect subsidiaries at the time, including EFIH, EFCH and TCEH, commenced proceedings under Chapter 11 of the U.S. Bankruptcy Code. The Oncor Ring-Fenced Entities were not parties to the EFH Bankruptcy Proceedings. In connection with the plans of reorganization in the EFH Bankruptcy Proceedings, on March 9, 2018, the Sempra Acquisition was completed. See Note 2 for further information.
Basis Of Presentation	Basis of Presentation  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 year.
Revenue Recognition	Revenue Recognition  General  Oncor’s revenue is billed under tariffs approved by the PUCT and the majority of revenues are related to providing electric delivery service to consumers. Tariff rates are designed to recover the cost of providing electric delivery service including a reasonable rate of return on invested capital. Revenues are generally recognized when the underlying service has been provided in an amount prescribed by the related tariff.  Reconcilable Tariffs  The PUCT has designated certain tariffs (TCRF, EECRF and previously AMS surcharges and charges related to transition bonds) as reconcilable, which means the differences between amounts billed under these tariffs and the related incurred costs are deferred as either regulatory assets or regulatory liabilities. Accordingly, at prescribed intervals, future tariffs are adjusted to either repay regulatory liabilities or collect regulatory assets. See “Regulatory Assets and Liabilities” below.  See Note 4 for additional information regarding revenues.
Impairment Of Long-Lived Assets And Goodwill	Impairment of Long-Lived Assets and Goodwill  We evaluate long-lived assets (including intangible assets with finite lives) for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. We also evaluate goodwill for impairment annually and whenever events or changes in circumstances indicate that an impairment may exist. The determination of the existence of these and other indications of impairment involves judgments that are subjective in nature and may require the use of estimates in forecasting future results and cash flows. Beginning in 2018, we elected to change our annual goodwill assessment date from December 1 to October 1 to correspond with the assessment date of our new majority owner. We do not believe this change in the assessment date is a material change.  If at the assessment date our carrying value exceeds our estimated fair value (enterprise value), then the estimated enterprise value is compared to the estimated fair values of our operating assets (including identifiable intangible assets) and liabilities at the assessment date. The resultant implied goodwill amount is compared to the recorded goodwill amount. Any excess of the recorded goodwill amount over the implied goodwill amount is written off as an impairment charge.  In October 2018, December 2017 and December 2016, we concluded, based on a qualitative assessment, that our estimated enterprise fair value was more likely than not greater than our carrying value. As a result , no additional testing for impairment was required and n o impairments were recognized in 2018, 2017 or 2016 .
Provision In Lieu Of Income Taxes	Provision in Lieu of Income Taxes  Our tax sharing agreement with Oncor Holdings, Texas Transmission and STH (as successor to EFH Corp.) provides for the calculation of amounts related to income taxes for each of Oncor Holdings and Oncor substantially as if these entities were taxed as corporations and requires payments to the members determined on that basis (without duplication for any income taxes paid by a subsidiary of Oncor Holdings).  We are a partnership for U.S. federal income tax purposes and remain a partnership for U.S. federal income tax purposes after the closing of the Sempra Acquisition. Accordingly, while partnerships are not subject to income taxes, in consideration of the presentation of our financial statements as an entity subject to cost-based regulatory rate-setting processes, with such costs historically including income taxes, the financial statements present amounts determined under the tax sharing agreement as “provision in lieu of income taxes” and “liability in lieu of deferred income taxes”. Such amounts are determined in accordance with the provisions of the accounting guidance for income taxes and accounting standards that provide interpretive guidance for accounting for uncertain tax positions and thus differences between the book and tax bases of assets and liabilities are accounted for as if we were a stand-alone corporation. 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.  We classify any interest and penalties expense related to uncertain tax positions as current provision in lieu of income taxes as discussed in Note 5.
Defined Benefit Pension Plans And OPEB Plans	Defined Benefit Pension Plans and OPEB Plans  We have liabilities under pension plans that offer benefits based on either a traditional defined benefit formula or a cash balance formula and OPEB plans that offer certain health care and life insurance benefits to eligible employees and their eligible dependents upon the retirement of such employees from the company. Costs of pension and OPEB plans are dependent upon numerous factors, assumptions and estimates. See Note 10 for additional information regarding pension and OPEB plans.
System Of Accounts	System of Accounts  Our accounting records have been maintained in accordance with the FERC Uniform System of Accounts as adopted by the PUCT.
Property, Plant And Equipment	Property, Plant and Equipment  Properties are stated at original cost. The cost of self-constructed property additions includes materials and both direct and indirect labor and applicable overhead and an allowance for funds used during construction.  D epreciation of property, plant and equipment is calculated on a straight-line basis over the estimated service lives of the properties based on depreciation rates approved by the PUCT. As is common in the industry, depreciation expense is recorded using composite depreciation rates that reflect blended estimates of the lives of major asset groups as compared to depreciation expense calculated on a component asset-by-asset basis. Depreciation rates include plant removal costs as a component of depreciation expense, consistent with regulatory treatment. Actual removal costs incurred are charged to accumulated depreciation. Accrued removal costs in excess of incurred removal costs are reclassified as a regulatory liability to retire assets in the future.
Regulatory Assets And Liabilities	Regulatory Assets and Liabilities  We are subject to rate regulation and our financial statements reflect regulatory assets and liabilities in accordance with accounting standards related to the effect of certain types of regulation. Regulatory assets and liabilities represent probable future revenues that will be recovered from or refunded to customers through the ratemaking process based on PURA and/or the PUCT’s orders, precedents or substantive rules. Rate regulation is premised on the full recovery of prudently incurred costs and a reasonable rate of return on invested capital subject to PUCT review for reasonableness and prudence and possible disallowance. Regulatory decisions can have an impact on the recovery of costs, the rate earned on invested capital and the timing and amount of assets to be recovered by rates. See Note 3 for more information regarding regulatory assets and liabilities. 
Franchise Taxes	 Franchise Taxes  Franchise taxes are assessed to us by local governmental bodies, based on kWh delivered and are a principal component of taxes other than amounts related to income taxes as reported in the income statement. Franchise taxes are not a “pass through” item. The rates we charge customers are intended to recover the franchise taxes, but we are not acting as an agent to collect the taxes from customers.
Allowance For Funds Used During Construction (AFUDC)	Allowance for Funds Used During Construction (AFUDC)  AFUDC is a regulatory cost accounting procedure whereby both interest charges on borrowed funds and a return on equity capital used to finance construction are included in the recorded cost of utility plant and equipment being constructed. AFUDC is capitalized on all projects involving construction periods lasting greater than thirty days. The equity portion, if any, of capitalized AFUDC is accounted for as other income. See Note 13 for detail of amounts reducing interest expense.
Cash And Cash Equivalents	Cash and Cash Equivalents  For purposes of reporting cash and cash equivalents, temporary cash investments purchased with an original maturity of three months or less are considered to be cash equivalents.
Fair Value Of Nonderivative Financial Instruments	Fair Value of Nonderivative Financial Instruments  The carrying amounts for financial assets classified as current assets and the carrying amounts for financial liabilities classified as current liabilities approximate fair value due to the short maturity of such instruments. The fair values of other financial instruments, for which carrying amounts and fair values have not been presented, are not materially different than their related carrying amounts. The following discussion of fair value accounting standards applies primarily to our determination of the fair value of assets in the pension and OPEB plans’ trusts (see Note 10) and long-term debt (see Note 7).  Accounting standards related to the determination of fair value define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. We use a “mid-market” valuation convention (the mid-point price between bid and ask prices) as a practical expedient to measure fair value for the majority of our assets and liabilities subject to fair value measurement on a recurring basis. We primarily use the market approach for recurring fair value measurements and use valuation techniques to maximize the use of observable inputs and minimize the use of unobservable inputs.  We categorize our assets and liabilities recorded at fair value based upon the following fair value hierarchy:  · Level 1 valuations use quoted prices in active markets for identical assets or liabilities that are accessible at the measurement date. An active market is a market in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis.  · Level 2 valuations use inputs that, in the absence of actively quoted market prices, are observable for the asset or liability, either directly or indirectly. Level 2 inputs include: (a) quoted prices for similar assets or liabilities in active markets , (b) quoted prices for identical or similar assets or liabilities in markets that are not active, (c) inputs other than quoted prices that are observable for the asset or liability such as interest rates and yield curves observable at commonly quoted intervals and (d) inputs that are derived principally from or corroborated by observable market data by correlation or other means. Our Level 2 valuations utilize over-the-counter broker quotes, quoted prices for similar assets or liabilities that are corroborated by correlations or other mathematical means and other valuation inputs.  · Level 3 valuations use unobservable inputs for the asset or liability. Unobservable inputs are used to the extent observable inputs are not available, thereby allowing for situations in which there is little, if any, market activity for the asset or liability at the measurement date. We use the most meaningful information available from the market combined with internally developed valuation methodologies to develop our best estimate of fair value.  We utilize several different valuation techniques to measure the fair value of assets and liabilities, relying primarily on the market approach of using prices and other market information for identical and/or comparable assets and liabilities for those items that are measured on a recurring basis.  The fair value of certain investments is measured using the net asset value (NAV) per share as a practical expedient. Such investments measured at NAV are not required to be categorized within the fair value hierarchy.
Consolidation Of Variable Interest Entities	Consolidation of Variable Interest Entities  A VIE is an entity with which we have a relationship or arrangement that indicates some level of control over the entity or results in economic risks to us. We consolidate a VIE if we have: a) the power to direct the significant activities of the VIE and b) the right or obligation to absorb profit and loss from the VIE (primary beneficiary). See Note 13.
Derivative Instruments And Mark-To-Market Accounting	Derivative Instruments and Mark-to-Market Accounting  We have from time-to-time entered into derivative instruments to hedge interest rate risk. If the instrument meets the definition of a derivative under accounting standards related to derivative instruments and hedging activities, the fair value of each derivative is recognized on the balance sheet as a derivative asset or liability and changes in the fair value are recognized in net income, unless criteria for certain exceptions are met. This recognition is referred to as “mark-to-market” accounting.
Changes In Accounting Standards	Changes in Accounting Standards  Topic 606, “Revenue from Contracts with Customers” - Since May 2014, the Financial Accounting Standards Board (FASB) has issued Accounting Standards Update (ASU) 2014-09, along with other supplemental guidance (together, Topic 606). Topic 606 introduced new, increased requirements for disclosure of revenue in financial statements and guidance intended to eliminate inconsistencies in the recognition of revenue. We adopted Topic 606 effective January 1, 2018 using the modified retrospective approach and elected the practical expedient available that allows an entity to recognize revenue in the amount to which the entity has the right to invoice related to performance completed to date. Our revenues are generally recognized when the underlying service has been provided in an amount prescribed by the related tariff. The new guidance did not change this pattern of recognition and therefore the adoption did not have a material effect on our reported results of operations, financial position or cash flows. Topic 606 also requires the separate presentation of “alternative revenue program” revenues on the income statement. We recorded $7 million in alternative revenue program revenues in 2018 related to our energy efficiency program and disclosed such activity in Note 4. See Note 4 for additional disclosures about revenues from contracts with customers.  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 regulatory purposes. Under current standards, all of Oncor’s existing leases meet the definition of an operating lease. Under the new rules, the recognition of any finance leases (currently known as capital leases) on the balance sheet would be classified as debt for GAAP purposes and are expected to be defined as debt for our regulatory capital structure purposes (see Note 9 for details) similar to the current capital lease treatment. We adopted Topic 842 on January 1, 2019 and will use certain practical expedients and policy elections available under the guidance including a practical expedient to not assess whether existing land easements that were not previously accounted for as leases are or contain a lease under Topic 842, an adoption method to not restate comparative periods and a policy election to forego the application of Topic 842 recognition requirements to short-term leases. The initial adoption of Topic 842 will affect our 2019 balance sheet, as our contracts for office space and fleet vehicles are currently classified as operating leases. The initial adoption of Topic 842 is expected to result in the recording of operating lease assets and operating lease obligations each in the amount of approximately $100 million with no impact to results of operations or cash flows.  Topic 715, “Compensation – Retirement Benefits” amended by ASU 2017-07, “Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost” - In March 2017, the FASB issued ASU 2017-07, an amendment to Topic 715. ASU 2017-07 requires the non-service cost components of net retirement benefit plan costs be presented as non-operating in the income statement. In addition, only the service cost component of net retirement benefit plan cost is eligible for capitalization as part of inventory or property, plant and equipment. We adopted ASU 2017-07 on January 1, 2018. The presentation of costs is required to be applied on a retrospective basis while the capitalization eligibility requirement is applied on a prospective basis. The guidance allows a practical expedient that permits use of previously disclosed service costs and non-service costs of the Pension and OPEB Plans in the comparative periods as appropriate estimates when recasting the presentation of these costs in the income statements. We have elected this practical expedient. For cash flow purposes on a prospective basis, non-service costs will be reflected as a reduction to operating cash flows, offset by lower cash used in investing activities (lower capital expenditures). The new guidance did not have a material effect on our results of operations, financial position or net change in total cash flows and we do not expect the guidance to have a material effect on our rate-making process. For the years 2016 and 2017, the adoption of ASU 2017-07 resulted in a reclassification of expense of $28 million and $31 million from operation and maintenance expense to other income and (deductions), respectively, and a corresponding reclassification of benefit of $10 million and $11 million, respectively, from provision in lieu of income taxes to nonoperating provision in lieu of income taxes.  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. ASU 2018-02 allows a reclassification from accumulated other comprehensive income (AOCI) to capital accounts for stranded tax effects resulting from the TCJA which we expect to elect. Under ASU 2018-02, an entity will be required to provide certain disclosures regarding stranded tax effects, including its accounting policy related to releasing the income tax effects from AOCI. Our stranded tax effects in AOCI are approximately $4 million and will increase our capital account upon reclassification. ASU 2018-02 can be applied either as of the beginning of the period of adoption or retrospectively as of the date of enactment of the TCJA and to each period in which the effect of the TCJA is recognized. ASU 2018-02 is effective for our 2019 annual reporting period, including interim periods therein, with early adoption permitted. We adopted the standard on a prospective basis, January 1, 2019.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2018
Regulatory Matters [Abstract]
Components Of Regulatory Assets And Liabilities	  Remaining Rate Recovery/Amortization Period at At December 31,  December 31, 2018 2018 2017   Regulatory assets:  Employee retirement liability (a)(b)(c) To be determined $ 648 $ 854  Employee retirement costs being amortized 9 years 297 331  Employee retirement costs incurred since the last rate review period (b) To be determined 73 30  Self-insurance reserve (primarily storm recovery costs) being amortized 9 years 351 394  Self-insurance reserve incurred since the last rate review period (b) To be determined 59 49  Securities reacquisition costs Lives of related debt 10 12  Deferred conventional meter and metering facilities depreciation 2 years 36 57  Under-recovered AMS costs 9 years 185 206  Excess deferred taxes Various - 197  Energy efficiency performance bonus (a) 1 year or less 7 12  Other regulatory assets Various 25 38  Total regulatory assets 1,691 2,180   Regulatory liabilities:  Estimated net removal costs Lives of related assets 1,023 954  Excess deferred taxes Primarily over lives of related assets 1,571 1,789  Over-recovered wholesale transmission service expense (a) 1 year or less 89 47  Other regulatory liabilities Various 14 17  Total regulatory liabilities 2,697 2,807  Net regulatory assets (liabilities) $ (1,006) $ (627) ____________ (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)	12 Months Ended
	Dec. 31, 2018
Revenues [Abstract]
Disaggregation Of Revenues	  Year Ended December 31,  2018   Operating revenues  Revenues contributing to earnings:  Distribution base revenues $ 2,139  Transmission base revenues (TCOS revenues)  Billed to third-party wholesale customers 548  Billed to REPs serving Oncor distribution customers, through TCRF 310  Total transmission base revenues 858  Other miscellaneous revenues 71  Total revenues contributing to earnings 3,068   Revenues collected for pass-through expenses:  TCRF - third-party wholesale transmission service 962  EECRF and other regulatory charges 71  Revenues collected for pass-through expenses 1,033   Total operating revenues $ 4,101 

Provision In Lieu Of Income T_2

Provision In Lieu Of Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Provision In Lieu Of Income Taxes [Abstract]
Schedule Of Deferred Tax Assets and Liabilities	  At December 31,  2018 2017   Deferred Tax Related Assets:  Employee benefit liabilities $ 234 $ 253  Regulatory liabilities 55 15  Other 6 7  Total 295 275  Deferred Tax Related Liabilities:  Property, plant and equipment 1,651 1,551  Regulatory assets 245 240  Other 1 1  Total 1,897 1,792  Liability in lieu of deferred income taxes - net $ 1,602 $ 1,517 
Components Of Income Tax Provisions (Benefits)	  Year Ended December 31,  2018 2017 (1) 2016 (1)   Reported in operating expenses:  Current:  U.S. federal $ 112 $ (55) $ 60  State 21 20 20  Deferred:  U.S. federal 21 303 191  State - - -  Amortization of investment tax credits (2) (2) (2)  Total reported in operating expenses 152 266 269  Reported in other income and deductions:  Current:  U.S. federal (32) (5) (5)  State - - -  Deferred federal (3) 6 (10)  Total reported in other income and deductions (35) 1 (15)  Total provision in lieu of income taxes $ 117 $ 267 $ 254 ________________ (1) As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1. 
Schedule Of Income Tax Reconciliation	  Year Ended December 31,  2018 2017 2016   Income before provision in lieu of income taxes $ 662 $ 686 $ 685  Provision in lieu of income taxes at the U.S. federal statutory rate of 21% for 2018 and 35% for 2017 and 2016 $ 139 $ 240 $ 240  Amortization of investment tax credits – net of deferred tax effect (2) (2) (2)  Amortization of excess deferred taxes (18) (1) (1)  Impact of federal statutory rate change from 35% to 21% - 21 -  Texas margin tax, net of federal tax benefit 17 13 13  Nontaxable gains on benefit plan investments (1) (4) -  Other, including audit settlements (18) - 4  Reported provision in lieu of income taxes $ 117 $ 267 $ 254  Effective rate 17.7% 38.9% 37.1% 
Schedule Of Changes To Uncertain Tax Positions	  2017 2016   Balance at January 1, excluding interest and penalties $ 3 $ 3  Reductions based on tax positions related to prior years (3) -  Balance at December 31, excluding interest and penalties $ - $ 3 

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	12 Months Ended
	Dec. 31, 2018
Short-Term Borrowings [Abstract]
Schedule Of Short-Term Borrowings	   At December 31,  2018 2017  Total borrowing capacity $ 2,000 $ 2,000  Commercial paper outstanding (a) (813) -  Credit facility outstanding (b) - (950)  Letters of credit outstanding (c) (9) (9)  Available unused credit $ 1,178 $ 1,041  ____________ a) The weighted average interest rate for commercial paper at December 31, 2018 was 2.74% . b) The weighted average interest rate for the Credit Facility at December 31, 2017 was 2.62% . c) Interest rates on outstanding letters of credit at December 31, 2018 and December 31, 2017 were 1.200% and 1.325% , respectively, based on our credit ratings.

Long-Term Debt (Tables)

Long-Term Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Long-Term Debt [Abstract]
Schedule Of Long-Term Debt	  December 31,  2018 2017   Secured:  6.80% Fixed Senior Notes due September 1, 2018 $ - $ 550  2.15% Fixed Senior Notes due June 1, 2019 250 250  5.75% Fixed Senior Notes due September 30, 2020 126 126  4.10% Fixed Senior Notes due June 1, 2022 400 400  7.00% Fixed Debentures due September 1, 2022 482 800  2.95% Fixed Senior Notes due April 1, 2025 350 350  3.70% Fixed Senior Notes due November 15, 2028 350 -  5.75% Fixed Senior Notes due March 15, 2029 318 -  7.00% Fixed Senior Notes due May 1, 2032 500 500  7.25% Fixed Senior Notes due January 15, 2033 350 350  7.50% Fixed Senior Notes due September 1, 2038 300 300  5.25% Fixed Senior Notes due September 30, 2040 475 475  4.55% Fixed Senior Notes due December 1, 2041 400 400  5.30% Fixed Senior Notes due June 1, 2042 500 500  3.75% Fixed Senior Notes due April 1, 2045 550 550  3.80% Fixed Senior Notes due September 30, 2047 325 325  4.10% Fixed Senior Notes due November 15, 2048 450 -  Secured long-term debt 6,126 5,876  Unsecured:  Term loan credit agreement due no later than March 26, 2019 - 275  Term loan credit agreement maturing December 9, 2019 350 -  Total long-term debt 6,476 6,151  Unamortized discount and debt issuance costs (41) (34)  Less amount due currently (600) (550)  Long-term debt, less amounts due currently $ 5,835 $ 5,567 
Schedule Of Long-Term Debt Maturity	  Year Amount  2019 $ 600  2020 126  2021 -  2022 882  2023 -  Thereafter 4,868  Unamortized discount and debt issuance costs (41)  Total $ 6,435 

Commitments And Contingencies (

Commitments And Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies [Abstract]
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)	12 Months Ended
	Dec. 31, 2018
Membership Interests [Abstract]
Schedule Of Distributions Paid	During 2018, our board of directors declared, and we paid, the following cash distributions to our members:    Declaration Date Payment Date Amount  October 24, 2018 November 6, 2018 $ 179  July 25, 2018 August 1, 2018 $ 30  During 2017, our board of directors declared, and we paid, the following cash distributions to our members:    Declaration Date Payment Date Amount  July 26, 2017 August 1, 2017 $ 65  April 26, 2017 April 27, 2017 $ 86  March 22, 2017 March 24, 2017 $ 86 
Schedule Of Cash Capital Contributions	During 2018, we received the following capital cash contributions from our members.    Received Amount  November 2018 $ 140  April 2018 $ 144 
Schedule Of Changes To Accumulated Other Comprehensive Income (Loss)	The following table presents the changes to accumulated other comprehensive income (loss) for the years ended December 31, 2018, 2017 and 2016 net of tax.   Cash Flow Hedges – Interest Rate Swap Defined Benefit Pension and OPEB Plans Accumulated Other Comprehensive Income (Loss)   Balance at December 31, 2015 $ (22) $ (91) $ (113)  Defined benefit pension plans - - -  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2016 $ (20) $ (91) $ (111)  Defined benefit pension plans - 8 8  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2017 $ (18) $ (83) $ (101)  Defined benefit pension plans - (65) (65)  Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges 2 - 2  Balance at December 31, 2018 $ (16) $ (148) $ (164) 

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Schedule Of Pension And OPEB Plan Costs	  Year Ended December 31,  2018 2017 2016   Pension costs $ 77 $ 85 $ 76  OPEB costs 70 58 62  Total benefit costs 147 143 138  Less amounts recognized principally as property or a regulatory asset (69) (98) (100)  Net amounts recognized as operation and maintenance expense or other deductions $ 78 $ 45 $ 38 
Schedule Of Detailed Pension And OPEB Benefit Information	  Pension Plans OPEB Plans  Year Ended December 31, Year Ended December 31,  2018 2017 2016 2018 2017 2016   Assumptions Used to Determine Net Periodic Pension and OPEB Costs:  Discount rate 3.54% 4.05% 4.30% 3.73% 4.35% 4.60%  Expected return on plan assets 5.11% 5.17% 5.54% 6.20% 6.10% 6.30%  Rate of compensation increase 4.46% 3.33% 3.29% - - -   Components of Net Pension and OPEB Costs:  Service cost $ 27 $ 24 $ 23 $ 8 $ 7 $ 7  Interest cost 121 131 134 44 47 49  Expected return on assets (120) (115) (122) (9) (8) (9)  Amortization of prior service cost (credit) - - - (30) (20) (20)  Amortization of net loss 49 45 41 57 32 35  Net periodic pension and OPEB costs $ 77 $ 85 $ 76 $ 70 $ 58 $ 62   Other Changes in Plan Assets and Benefit Obligations Recognized as Regulatory Assets or in Other Comprehensive Income:  Net loss (gain) $ 67 $ (11) $ 41 $ (177) $ 139 $ 10  Amortization of net loss (49) (45) (41) (57) (32) (35)  Plan amendments - - - - (78) -  Amortization of prior service (cost) credit - - - 30 20 20  Total recognized as regulatory assets or other comprehensive income 18 (56) - (204) 49 (5)  Total recognized in net periodic pension and OPEB costs and as regulatory assets or other comprehensive income $ 95 $ 29 $ 76 $ (134) $ 107 $ 57 
Schedule Of Assumptions Used	  Pension Plans OPEB Plans  Year Ended December 31, Year Ended December 31,  2018 2017 2016 2018 2017 2016   Assumptions Used to Determine Benefit Obligations at Period End:  Discount rate 4.18% 3.54% 4.05% 4.41% 3.73% 4.35%  Rate of compensation increase 4.53% 4.46% 3.33% - - - 
Schedule Of Changes In Projected Benefit Obligations And Changes In Fair Value Of Plan Assets And Net Funded Status	  Pension Plans OPEB Plans  Year Ended December 31, Year Ended December 31,  2018 2017 2018 2017   Change in Projected Benefit Obligation:  Projected benefit obligation at beginning of year $ 3,500 $ 3,307 $ 1,198 $ 1,116  Service cost 27 24 8 7  Interest cost 121 131 44 47  Participant contributions - - 19 19  Plan amendments - - - (78)  Actuarial (gain) loss (232) 201 (196) 154  Benefits paid (175) (163) (67) (67)  Annuity purchase (79) - - -  Projected benefit obligation at end of year $ 3,162 $ 3,500 $ 1,006 $ 1,198  Accumulated benefit obligation at end of year $ 3,069 $ 3,387 $ - $ -   Change in Plan Assets:  Fair value of assets at beginning of year $ 2,600 $ 2,287 $ 149 $ 143  Actual return (loss) on assets (179) 327 (10) 23  Employer contributions 82 149 41 31  Participant contributions - - 19 19  Benefits paid (175) (163) (67) (67)  Annuity purchase (79) - - -  Fair value of assets at end of year $ 2,249 $ 2,600 $ 132 $ 149   Funded Status:  Projected benefit obligation at end of year $ (3,162) $ (3,500) $ (1,006) $ (1,198)  Fair value of assets at end of year 2,249 2,600 132 149  Funded status at end of year $ (913) $ (900) $ (874) $ (1,049) 
Schedule Of Amounts Recognized In Balance Sheet	  Pension Plans OPEB Plans  Year Ended December 31, Year Ended December 31,  2018 2017 2018 2017   Amounts Recognized in the Balance Sheet Consist of:  Liabilities:  Other current liabilities $ (4) $ (4) $ (7) $ (12)  Other noncurrent liabilities (909) (896) (867) (1,037)  Net liability recognized $ (913) $ (900) $ (874) $ (1,049)  Regulatory assets:  Net loss $ 534 $ 538 $ 171 $ 402  Prior service cost (credit) - - (57) (86)  Net regulatory asset recognized $ 534 $ 538 $ 114 $ 316  Accumulated other comprehensive net loss $ 147 $ 124 $ 1 $ 3 
Schedule Of Projected Benefit Obligations And Accumulated Benefit Obligations In Excess Of Plan Assets Fair Value	  At December 31,  2018 2017   Pension Plans with PBO and ABO in Excess of Plan Assets:  Projected benefit obligations $ 3,162 $ 3,316  Accumulated benefit obligations 3,069 3,207  Plan assets 2,249 2,409 
Schedule Of Target Asset Allocation Ranges By Asset Category	  Target Allocation Ranges  Asset Category Recoverable Non-recoverable   International equities 13% - 21% 6% - 12%  U.S. equities 16% - 24% 8% - 14%  Real estate 3% - 7% -  Credit strategies 5% - 10% 5% - 9%  Fixed income 45% - 55% 68% - 78% 
Schedule Of Expected Long-Term Rate Of Return On Assets Assumptions	  Pension Plans OPEB Plans  Asset Class Expected Long-Term Rate of Return Asset Class Expected Long-Term Rate of Return   International equity securities 7.70% 401(h) accounts 6.63%  U.S. equity securities 6.60% Life insurance VEBA 6.08%  Real estate 5.40% Union VEBA 6.08%  Credit strategies 5.58% Non-union VEBA 2.90%  Fixed income securities 4.30% Weighted average 6.19%  Weighted average (a) 5.64% _____________ (a) The 2019 expected long-term rate of return for the nonregulated portion of the Oncor Retirement Plan is 4.91%, and for Oncor's portion of the Vistra Retirement Plan is 5.29% . 
Schedule Of Contributions	  Year Ended December 31,  2018 2017 2016   Pension plans contributions $ 82 $ 149 $ 4  OPEB plans contributions 41 31 31  Total contributions $ 123 $ 180 $ 35 
Schedule Of Estimated Future Benefit Payments	  2019 2020 2021 2022 2023 2024-28   Pension plans $ 183 $ 187 $ 192 $ 196 $ 200 $ 1,031  OPEB plans $ 53 $ 56 $ 58 $ 61 $ 63 $ 320 
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule Of Assets Fair Value Measured On Recurring Basis	  At December 31, 2018  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ - $ - $ - $ -  Equity securities:  U.S. 170 2 - 172  International 239 - - 239  Fixed income securities:  Corporate bonds (a) - 930 - 930  U.S. Treasuries - 110 - 110  Other (b) - 69 - 69  Real estate - - 3 3  Total assets in the fair value hierarchy $ 409 $ 1,111 $ 3 1,523  Total assets measured at net asset value (c) 726  Total fair value of plan assets $ 2,249   At December 31, 2017  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ - $ 11 $ - $ 11  Equity securities:  U.S. 235 2 - 237  International 271 - - 271  Fixed income securities:  Corporate bonds (a) - 1,081 - 1,081  U.S. Treasuries - 251 - 251  Other (b) - 44 - 44  Real estate - - 3 3  Total assets in the fair value hierarchy $ 506 $ 1,389 $ 3 1,898  Total assets measured at net asset value (c) 702  Total fair value of plan assets $ 2,600 _____________ (a) Substantially all corporate bonds are rated investment grade by a major ratings agency such as Moody’s. (b) Other consists primarily of municipal bonds, emerging market debt, bank loans and fixed income derivative instruments. (c) Fair value was measured using the net asset value (NAV) per share as a practical expedient as the investments did not have a readily determinable fair value and are not required to be classified in the fair value hierarchy. The NAV fair value amounts presented here are intended to permit a reconciliation to the total fair value of plan assets.
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule Of Assets Fair Value Measured On Recurring Basis	  At December 31, 2018  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ 15 $ - $ - $ 15  Equity securities:  U.S. 21 - - 21  International 22 - - 22  Fixed income securities:  Corporate bonds (a) - 26 - 26  U.S. Treasuries - 3 - 3  Other (b) 28 1 - 29  Total assets in the fair value hierarchy $ 86 $ 30 $ - 116  Total assets measured at net asset value (c) 16  Total fair value of plan assets $ 132   At December 31, 2017  Level 1 Level 2 Level 3 Total   Asset Category  Interest-bearing cash $ 1 $ 1 $ - $ 2  Equity securities:  U.S. 35 - - 35  International 33 - - 33  Fixed income securities:  Corporate bonds (a) - 30 - 30  U.S. Treasuries - 3 - 3  Other (b) 28 1 - 29  Total assets in the fair value hierarchy $ 97 $ 35 $ - 132  Total assets measured at net asset value (c) 17  Total fair value of plan assets $ 149 _____________ (a) Substantially all corporate bonds are rated investment grade by a major ratings agency such as Moody’s. (b) Other consists primarily of diversified bond mutual funds. (c) Fair value was measured using the net asset value (NAV) per share as a practical expedient as the investments did not have a readily determinable fair value and are not required to be classified in the fair value hierarchy. The NAV fair value amounts presented here are intended to permit a reconciliation to the total fair value of plan assets.
Postretirement Health Coverage [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule Of Assumptions Used	  Year Ended December 31,  2018 2017   Assumed Health Care Cost Trend Rates – Not Medicare Eligible:  Health care cost trend rate assumed for next year 7.60% 8.00%  Rate to which the cost trend is expected to decline (the ultimate trend rate) 4.50% 4.50%  Year that the rate reaches the ultimate trend rate 2026 2026   Assumed Health Care Cost Trend Rates – Medicare Eligible:  Health care cost trend rate assumed for next year 8.70% 9.40%  Rate to which the cost trend is expected to decline (the ultimate trend rate) 4.50% 4.50%  Year that the rate reaches the ultimate trend rate 2027 2026   1-Percentage Point Increase 1-Percentage Point Decrease   Sensitivity Analysis of Assumed Health Care Cost Trend Rates:  Effect on accumulated postretirement obligation $ 124 $ (103)  Effect on postretirement benefits cost 7 (5) 

Related-Party Transactions (Tab

Related-Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2018
Related-Party Transactions [Abstract]
Schedule Of Related Party Transactions	Amounts payable to (receivable from) members related to income taxes under the agreement and reported on our balance sheet consisted of the following:    At December 31, 2018 At December 31, 2017  STH Texas Transmission Total EFH Corp. Texas Transmission Total   Federal income taxes payable (receivable) $ 4 $ 1 $ 5 $ (21) $ (5) $ (26)  Texas margin taxes payable 21 - 21 21 - 21  Net payable (receivable) $ 25 $ 1 $ 26 $ - $ (5) $ (5)  Cash payments made to (received from) members related to income taxes consisted of the following:   Year Ended December 31, 2018 Year Ended December 31, 2017 Year Ended December 31, 2016  STH EFH Corp. Texas Transm. Total EFH Corp. Texas Transm. Total EFH Corp.   Federal income taxes $ 59 $ (19) $ 10 $ 50 $ (102) $ (12) $ (114) $ -  Texas margin taxes 21 - - 21 20 - 20 20  Total payments (receipts) $ 80 $ (19) $ 10 $ 71 $ (82) $ (12) $ (94) $ 20 

Supplementary Financial Infor_2

Supplementary Financial Information (Tables)	12 Months Ended
	Dec. 31, 2018
Supplementary Financial Information [Abstract]
Schedule Of Other Income And (Deductions)	Other Income and (Deductions)   Year Ended December 31,  2018 2017 2016   Professional fees $ (12) $ (15) $ (15)  Sempra Acquisition related costs (12) - -  Recoverable Pension and OPEB - non-service costs (a) (53) (31) (28)  Non-recoverable pension and OPEB (Note 10) (6) (5) (2)  Interest income 1 6 2  Other (2) (1) -  Total other income and (deductions) - net $ (84) $ (46) $ (43) ________________ (a) Years 2017 and 2016 are adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1. 
Schedule Of Interest Expense And Related Charges	  Year Ended December 31,  2018 2017 2016   Interest $ 358 $ 351 $ 341  Amortization of debt issuance costs and discounts 6 3 3  Less allowance for funds used during construction – capitalized interest portion (13) (12) (8)  Total interest expense and related charges $ 351 $ 342 $ 336 
Schedule Of Trade Accounts And Other Receivables	  At December 31,  2018 2017   Gross trade accounts and other receivables $ 562 $ 638  Allowance for uncollectible accounts (3) (3)  Trade accounts receivable – net $ 559 $ 635 
Summary of Investments And Other Property	  At December 31,  2018 2017   Assets related to employee benefit plans, including employee savings programs $ 108 $ 111  Land 12 2  Total investments and other property $ 120 $ 113 
Schedule Of Property, Plant And Equipment	  Composite Depreciation Rate/ At December 31,  Avg. Life at December 31, 2018 2018 2017  Assets in service:  Distribution 2.8% / 35.1 years $ 13,105 $ 12,467  Transmission 2.9% / 34.4 years 8,568 7,870  Other assets 6.9% / 14.6 years 1,497 1,380  Total 23,170 21,717  Less accumulated depreciation 7,513 7,255  Net of accumulated depreciation 15,657 14,462  Construction work in progress 417 402  Held for future use 16 15  Property, plant and equipment – net $ 16,090 $ 14,879 
Schedule Of Intangible Assets	  At December 31, 2018 At December 31, 2017  Gross Gross  Carrying Accumulated Carrying Accumulated  Amount Amortization Net Amount Amortization Net  Identifiable intangible assets subject to amortization:  Land easements $ 464 $ 101 $ 363 $ 453 $ 96 $ 357  Capitalized software 787 385 402 679 339 340  Total $ 1,251 $ 486 $ 765 $ 1,132 $ 435 $ 697 
Schedule Of Estimated Aggregate Amortization Expenses	  Year Amortization Expense   2019 $ 50  2020 49  2021 49  2022 49  2023 49 
Schedule Of Employee Benefit Obligations And Other	  At December 31,  2018 2017   Retirement plans and other employee benefits $ 1,858 $ 2,035  Investment tax credits 8 10  Other 77 57  Total employee benefit obligations and other $ 1,943 $ 2,102 
Schedule Of Supplemental Cash Flow Information	  Year Ended December 31,  2018 2017 2016  Cash payments related to:   Interest $ 368 $ 345 $ 336  Less capitalized interest (13) (12) (8)  Interest payments (net of amounts capitalized) $ 355 $ 333 $ 328   Amount in lieu of income taxes:  Federal $ 50 $ (114) $ -  State 21 20 20  Total payments (refunds) in lieu of income taxes $ 71 $ (94) $ 20   Noncash Sharyland Asset Exchange costs $ - $ 383 $ -  Noncash construction expenditures (a) $ 174 $ 129 $ 122 ______________ (a) Represents end-of-period accruals.
Schedule Of Quarterly Information	  2018 First Quarter Second Quarter Third Quarter Fourth Quarter  Operating revenues $ 990 $ 1,021 $ 1,095 $ 995  Operating income 202 244 293 206  Net income 89 143 194 119   2017 First Quarter Second Quarter Third Quarter Fourth Quarter  Operating revenues $ 935 $ 964 $ 1,068 $ 991  Operating income (1) 164 202 252 190  Net income 73 112 157 77 

Description Of Business and S_3

Description Of Business and Significant Accounting Policies (Narrative) (Details) - USD ($)

3 Months Ended

12 Months Ended

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2017

Sep. 30, 2017

Jun. 30, 2017

Mar. 31, 2017

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Aug. 31, 2017

Dec. 31, 2004

Dec. 31, 2003

Business And Significant Accounting Polices [Line Items]

Goodwill impairment

$ 0

$ 0

$ 0

Revenues

$ 995,000,000

$ 1,095,000,000

$ 1,021,000,000

$ 990,000,000

$ 991,000,000

$ 1,068,000,000

$ 964,000,000

$ 935,000,000

Accounting Standards Update 2017-07 [Member]

Business And Significant Accounting Polices [Line Items]

Reclassification from operation and maintenance expense to other income and (deductions)

31,000,000

28,000,000

Increase in provision in lieu of income taxes and decrease in non-operating provision in lieu of income taxes

$ 11,000,000

$ 10,000,000

Accounting Standards Update 2018-02 [Member]

Business And Significant Accounting Polices [Line Items]

Reclassification from AOCI to membership interests for stranded tax effects

$ 4,000,000

Oncor Holdings [Member]

Business And Significant Accounting Polices [Line Items]

Ownership interests acquired

0.22%

Bondco [Member]

Business And Significant Accounting Polices [Line Items]

Principal amount of transition bonds issued

$ 1,300,000,000

$ 1,300,000,000

Oncor Holdings [Member]

Business And Significant Accounting Polices [Line Items]

Ownership

80.25%

80.25%

Texas Transmission [Member]

Business And Significant Accounting Polices [Line Items]

Percentage of membership interest owned by non-controlling owners

19.75%

19.75%

19.75%

Maximum [Member] | Accounting Standards Update 2016-02 [Member]

Business And Significant Accounting Polices [Line Items]

Operating lease obligations

$ 100,000,000

$ 100,000,000

EFH Bankruptcy Proceedings an_2

EFH Bankruptcy Proceedings and Sempra Acquisition (Narrative) (Details) - USD ($)	Apr. 23, 2018	Mar. 09, 2018	Nov. 27, 2017	Aug. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Bankruptcy [Line Items]
Cash paid						$ 25,000,000
Percent increase or decrease for disinterested directors to approve any budget					10.00%
Minimum aggregate capital expenditures					$ 7,500,000,000
Regulatory capitalization ratio, debt			57.50%		60.00%
Regulatory capitalization ratio, equity			42.50%		40.00%
Percent of savings for bill credits					90.00%
Period of bill credits					1 year
Sempra Energy [Member]
Bankruptcy [Line Items]
Cash paid	$ 117,000,000
Required time for holding owndership interests					5 years
Oncor Holdings [Member]
Bankruptcy [Line Items]
Ownership interests acquired				0.22%
Transaction or transition costs					$ 0
Sempra Energy [Member]
Bankruptcy [Line Items]
Cash paid				$ 9,450,000,000
Outstanding equity interests		1,396,008
Transaction or transition costs		$ 26,000,000
Number of days for proportionate share of aggregate equity investment					60 days
Texas Transmission [Member]
Bankruptcy [Line Items]
Percentage of membership interest owned by non-controlling owners				19.75%	19.75%
Sempra Energy [Member]
Bankruptcy [Line Items]
Percentage of membership interest owned by non-controlling owners					51.00%

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details) $ in Millions	Oct. 08, 2018USD ($)	Jul. 01, 2018USD ($)	Dec. 22, 2017USD ($)	Nov. 27, 2017	Jul. 21, 2017USD ($)mikW	Dec. 31, 2018USD ($)	May 31, 2018USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017	Dec. 31, 2016	Jun. 13, 2018USD ($)	Jun. 12, 2018USD ($)	Apr. 05, 2018USD ($)
Public Utilities, General Disclosures [Line Items]
U.S. federal statutory rate								21.00%	35.00%	35.00%
DCRF increase											$ 15	$ 19	$ 19
Decrease in revenue requirement						$ 181		$ 181
Annual rate reductions related to reduction in income taxes								144
Reduction related to amortization of excess deferred income taxes	$ 140	$ 79						37
Reduction of income tax expense								144
Reduction to income tax expense related to amortization of excess deferred federal income taxes								$ 75
Refund of tax rate differential						$ 73
Increase (decrease) in liability for deferred income taxes			$ 3
Authorized return on equity				9.80%				10.25%
Increase in regulatory liabililty							$ 6
Sharyland Merger Agreement [Member]
Public Utilities, General Disclosures [Line Items]
Transmission of assets					$ 383
Number of assets transferred in circuit miles | mi					517
Power of number of transmission lines transferred | kW					345

Regulatory Matters (Components

Regulatory Matters (Components Of Regulatory Assets And Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Regulatory Assets And Liabilities [Line Items]
Carrying Amount, Regulatory Assets	$ 1,691	$ 2,180
Carrying Amount, Regulatory Liabilities	2,697	2,807
Net regulatory assets (liabilities)	$ (1,006)	(627)
Estimated Net Removal Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	Lives of related assets
Carrying Amount, Regulatory Liabilities	$ 1,023	954
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	$ 1,571	1,789
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	$ 89	47
Other Regulatory Liabilities [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	Various
Carrying Amount, Regulatory Liabilities	$ 14	17
Employee Retirement Liability [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	To be determined
Carrying Amount, Regulatory Assets	$ 648	854
Employee Retirement Costs Being Amortized [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	9 years
Carrying Amount, Regulatory Assets	$ 297	331
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	$ 73	30
Self-Insurance Reserve (Primarily Storm Recovery Costs) Being Amortized [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	9 years
Carrying Amount, Regulatory Assets	$ 351	394
Self-Insurance Reserve 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	$ 59	49
Securities Reacquisition Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	Lives of related debt
Carrying Amount, Regulatory Assets	$ 10	12
Deferred Conventional Meter And Metering Facilities Depreciation [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	2 years
Carrying Amount, Regulatory Assets	$ 36	57
Under-recovered AMS Costs [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	9 years
Carrying Amount, Regulatory Assets	$ 185	206
Excess Deferred Taxes [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	Various
Carrying Amount, Regulatory Assets		197
Energy Efficiency Performance Bonus [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	1 year or less
Carrying Amount, Regulatory Assets	$ 7	12
Other Regulatory Assets [Member]
Regulatory Assets And Liabilities [Line Items]
Remaining Rate Recovery/Amortization Period	Various
Carrying Amount, Regulatory Assets	$ 25	$ 38

Revenues (Narrative) (Details)

Revenues (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)customeritem	Dec. 31, 2017	Dec. 31, 2016
Disaggregation of Revenue [Line Items]
Approved bonus | $	$ 7
Number of REPS | customer	90
Number of counterparties | item	2
REP Subsidiary One [Member] | Sales Revenue, Net [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	23.00%	22.00%	23.00%
REP Subsidiary Two [Member] | Sales Revenue, Net [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	19.00%	18.00%	17.00%

Revenues (Disaggregation Of Rev

Revenues (Disaggregation Of Revenues) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	[1]	Dec. 31, 2016	[1]
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	$ 3,068
Revenues collected for pass-through expenses	1,033
Total operating revenues	4,101	$ 3,958		$ 3,920
Distribution Base Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	2,139
Transmission Base Revenues (TCOS Revenues) [Member]
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	858
Transmission Base Revenues (TCOS Revenues) [Member] | Third-Party Wholesale Customers [Member]
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	548
Transmission Base Revenues (TCOS Revenues) [Member] | REPS Serving Oncor Distribution Customers, Through TCRF [Member]
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	310
Other Miscellaneous Revenues [Member]
Disaggregation of Revenue [Line Items]
Total revenues contributing to earnings	71
TCRF - Third-party Wholesale Transmission Service [Member]
Disaggregation of Revenue [Line Items]
Revenues collected for pass-through expenses	962
EECRF And Other Regulatory Charges [Member]
Disaggregation of Revenue [Line Items]
Revenues collected for pass-through expenses	$ 71
[1]	As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.

Provision In Lieu Of Income T_3

Provision In Lieu Of Income Taxes (Narrative) (Details) - USD ($)	Dec. 22, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Provision In Lieu Of Income Taxes [Abstract]
U.S. federal statutory rate		21.00%	35.00%	35.00%
Re-measurement of liability in lieu of deferred income taxes	$ 1,600,000,000		$ 21,000,000
Increase (decrease) in liability for deferred income taxes	$ 3,000,000
Net liability in lieu of deferred income taxes		$ 1,602,000,000	1,517,000,000
Uncertain tax positions related to timing of recognition				$ 3,000,000
Accrued interest		0	0
Benefit (expense) from interest and penalties		$ 0	$ 0	$ 0

Provision In Liew Of Income Tax

Provision In Liew Of Income Taxes (Schedule Of Components Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Provision In Lieu Of Income Taxes [Abstract]
Deferred tax assets, Employee benefit liabilities	$ 234	$ 253
Deferred tax assets, Regulatory liabilities	55	15
Deferred tax assets, Other	6	7
Total	295	275
Deferred tax liabilities, Property, plant and equipment	1,651	1,551
Deferred tax liabilities, Regulatory assets	245	240
Deferred Tax Liabilities, Other	1	1
Total	1,897	1,792
Liability in lieu of deferred income taxes - net	$ 1,602	$ 1,517

Provision In Lieu Of Income T_4

Provision In Lieu Of Income Taxes (Components Of Income Tax Provisions (Benefits)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Provision In Lieu Of Income Taxes [Abstract]
Current: U.S. federal	$ 112	$ (55)		$ 60
Current: State	21	20		20
Deferred: U.S. federal	21	303		191
Amortization of investment tax credits	(2)	(2)		(2)
Total reported in operating expenses	152	266	[1]	269	[1]
U.S. federal	(32)	(5)		(5)
Deferred federal	(3)	6		(10)
Total reported in other income and deductions	(35)	1		(15)
Total provision in lieu of income taxes	$ 117	$ 267		$ 254
[1]	As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.

Provision In Lieu Of Income T_5

Provision In Lieu Of Income Taxes (Schedule Of Income Tax Reconciliation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Provision In Lieu Of Income Taxes [Abstract]
Income before provision in lieu of income taxes	$ 662	$ 686	$ 685
Provision in lieu of income taxes at the U.S. federal statutory rate of 21% for 2018 and 35% for 2017 and 2016	139	240	240
Amortization of investment tax credits - net of deferred tax effect	(2)	(2)	(2)
Amortization of excess deferred taxes	(18)	(1)	(1)
Impact of federal statutory rate change 35% to 21%		21
Texas margin tax, net of federal tax benefit	17	13	13
Nontaxable gains on benefit plan investments	(1)	(4)
Other, including audit settlements	(18)		4
Total provision in lieu of income taxes	$ 117	$ 267	$ 254
Effective rate	17.70%	38.90%	37.10%
U.S. federal statutory rate	21.00%	35.00%	35.00%

Provision In Lieu Of Income T_6

Provision In Lieu Of Income Taxes (Schedule Of Changes To Uncertain Tax Positions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Provision In Lieu Of Income Taxes [Abstract]
Balance at January 1, excluding interest and penalties	$ 3	$ 3
Reductions based on tax positions related to prior years	(3)
Balance at December 31, excluding interest and penalties		$ 3

Short-Term Borrowings (Narrativ

Short-Term Borrowings (Narrative) (Details) $ in Millions	1 Months Ended	12 Months Ended
	Nov. 30, 2017USD ($)item	Dec. 31, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Line of Credit Facility [Line Items]
Commitment fee		0.125%
Borrowing capacity available under the credit facility		$ 2,000		$ 2,000
Maximum [Member]
Line of Credit Facility [Line Items]
Commitment fee		0.225%
Minimum [Member]
Line of Credit Facility [Line Items]
Commitment fee		0.075%
Letter of Credit [Member]
Line of Credit Facility [Line Items]
Outstanding borrowing under the revolving credit facility		$ 9		9
Outstanding borrowing, interest rate		1.20%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 2,000
Number of revolving credit facilities extension options | item	2
Extension period for revolving line of credit	1 year
Credit facility, term	5 years
Expiration of revolving credit facility		Nov. 1, 2022
Outstanding borrowing under the revolving credit facility				$ 950
Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Additional increase in borrowing capacity amount	$ 100
Debt-to-capitalization ratio		1
Revolving Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Additional increase in borrowing capacity amount	$ 400
Debt-to-capitalization ratio		0.65
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] | Maximum [Member]
Line of Credit Facility [Line Items]
Spread over variable rate		1.50%
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Spread over variable rate		0.875%
Federal Funds Effective Rate [Member]
Line of Credit Facility [Line Items]
Spread over variable rate		0.50%
One-Month London Interbank Offered Rate [Member]
Line of Credit Facility [Line Items]
Spread over variable rate		1.00%
One-Month London Interbank Offered Rate [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Spread over variable rate		0.50%
One-Month London Interbank Offered Rate [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Spread over variable rate		0.00%

Short-Term Borrowings (Schedule

Short-Term Borrowings (Schedule Of Short-Term Borrowings) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Short-term Debt [Line Items]
Total borrowing capacity	$ 2,000	$ 2,000
Available unused credit	1,178	1,041
Commercial Paper [Member]
Short-term Debt [Line Items]
Outstanding	(813)
Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Outstanding		(950)
Letter of Credit [Member]
Short-term Debt [Line Items]
Outstanding	$ (9)	$ (9)
Interest Rate	1.20%	1.325%
Weighted Average [Member] | Commercial Paper [Member]
Short-term Debt [Line Items]
Interest Rate	2.74%
Weighted Average [Member] | Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Interest Rate		2.62%

Long-Term Debt (Narrative) (Det

Long-Term Debt (Narrative) (Details) - USD ($)	Dec. 10, 2019	Dec. 09, 2019	Nov. 30, 2018	Aug. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Long-Term Debt [Line Items]
Repayments of long-term debt					$ 825,000,000	$ 324,000,000	$ 41,000,000
Proceeds from sale of Notes				$ 791,000,000
Excess of principal amount for default					$ 100,000,000
Time alloted for excess debt default to be discharged					60 days
Percentage of fair value of cost of property additions certified to the Deed of Trust collateral agent					85.00%
Available bond credits					$ 3,586,000,000
Future debt subject to property additions to the Deed of Trust					2,587,000,000
Estimated fair value of our long-term debt including current maturities					$ 7,086,000,000	$ 7,153,000,000
Federal Funds Effective Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate					0.50%
One-Month London Interbank Offered Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate					1.00%
Term Loan Credit Agreement Due No Later Than March 26, 2019 [Member]
Long-Term Debt [Line Items]
Repayments of long-term debt					$ 275,000,000
6.80% Fixed Senior Notes Due September 1, 2018 [Member]
Long-Term Debt [Line Items]
Repayments of long-term debt					$ 550,000,000
CP Progam [Member]
Long-Term Debt [Line Items]
Debt principal amount				$ 131,000,000
New Notes [Member]
Long-Term Debt [Line Items]
Redemption percentage					100.00%
2029 Notes And 2022 Notes [Member]
Long-Term Debt [Line Items]
Proceeds from sale of Notes			$ 0
Term Loan Credit Agreement Maturing December 9, 2019 [Member]
Long-Term Debt [Line Items]
Loan term					12 months
Extension option					6 months
Term Loan Credit Agreement Maturing December 9, 2019 [Member] | London Interbank Offered Rate (LIBOR) [Member] | Scenario, Forecast [Member]
Long-Term Debt [Line Items]
Spread over variable rate	0.60%	0.55%
Term Loan Credit Agreement Maturing December 9, 2019 [Member] | Federal Funds Effective Rate [Member] | Scenario, Forecast [Member]
Long-Term Debt [Line Items]
Spread over variable rate	0.50%
Term Loan Credit Agreement Maturing December 9, 2019 [Member] | One-Month London Interbank Offered Rate [Member] | Scenario, Forecast [Member]
Long-Term Debt [Line Items]
Spread over variable rate	1.00%
Minimum [Member]
Long-Term Debt [Line Items]
Senior debt to capitalization ratio					0.65
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Long-Term Debt [Line Items]
Spread over variable rate					0.875%
Minimum [Member] | One-Month London Interbank Offered Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate					0.00%
Maximum [Member]
Long-Term Debt [Line Items]
Senior debt to capitalization ratio					1
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]
Long-Term Debt [Line Items]
Spread over variable rate					1.50%
Maximum [Member] | One-Month London Interbank Offered Rate [Member]
Long-Term Debt [Line Items]
Spread over variable rate					0.50%

Long-Term Debt (Schedule Of Lon

Long-Term Debt (Schedule Of Long-Term Debt) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total long-term debt	$ 6,476	$ 6,151
Unamortized discount and debt issuance costs	(41)	(34)
Less amount due currently	(600)	(550)
Long-term debt, less amounts due currently	5,835	5,567
Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 6,126	$ 5,876
6.80% Fixed Senior Notes Due September 1, 2018 [Member]
Debt Instrument [Line Items]
Interest percentage	6.80%	6.80%
Due date	Sep. 1, 2018
6.80% Fixed Senior Notes Due September 1, 2018 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt		$ 550
2.15% Fixed Senior Notes Due June 1, 2019 [Member]
Debt Instrument [Line Items]
Interest percentage	2.15%	2.15%
Due date	Jun. 1, 2019
2.15% Fixed Senior Notes Due June 1, 2019 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 250	$ 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
5.75% Fixed Senior Notes Due September 30, 2020 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 126	$ 126
4.10% Fixed Senior Notes Due June 1, 2022 [Member]
Debt Instrument [Line Items]
Interest percentage	4.10%	4.10%
Due date	Jun. 1, 2022
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]
Due date	Sep. 1, 2022
7.00% Fixed Debentures Due September 1, 2022 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 482	800
2.95% Fixed Senior Notes Due April 1, 2025 [Member]
Debt Instrument [Line Items]
Interest percentage	2.95%
Due date	Apr. 1, 2025
2.95% Fixed Senior Notes Due April 1, 2025 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 350	$ 350
3.70% Fixed Senior Notes Due November 15, 2028 [Member]
Debt Instrument [Line Items]
Interest percentage	3.70%
Due date	Nov. 15, 2028
3.70% Fixed Senior Notes Due November 15, 2028 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 350
5.75% Fixed Senior otes Due March 15, 2029 [Member]
Debt Instrument [Line Items]
Interest percentage	5.75%	5.75%
Due date	Mar. 15, 2029
5.75% Fixed Senior otes Due March 15, 2029 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 318
7.00% Fixed Senior Notes Due May 1, 2032 [Member]
Debt Instrument [Line Items]
Interest percentage	7.00%	7.00%
Due date	May 1, 2032
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%
Due date	Jan. 15, 2033
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%
Due date	Sep. 1, 2038
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%
Due date	Sep. 30, 2040
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%
Due date	Dec. 1, 2041
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%
Due date	Jun. 1, 2042
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
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
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]
Interest percentage	4.10%	4.10%
Due date	Nov. 15, 2048
4.10% Fixed Senior Notes Due November 15, 2048 [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Secured long-term debt	$ 450
Term Loan Credit Agreement Due No Later Than March 26, 2019 [Member]
Debt Instrument [Line Items]
Due date	Mar. 26, 2019
Term Loan Credit Agreement Due No Later Than March 26, 2019 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Term loan		$ 275
Term Loan Credit Agreement Maturing December 9, 2019 [Member]
Debt Instrument [Line Items]
Due date	Dec. 9, 2019
Term Loan Credit Agreement Maturing December 9, 2019 [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Term loan	$ 350

Long-Term Debt (Schedule Of L_2

Long-Term Debt (Schedule Of Long-Term Debt Maturity) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Long-Term Debt [Abstract]
2,019	$ 600
2,020	126
2,022	882
Thereafter	4,868
Unamortized discount and debt issuance costs	(41)	$ (34)
Total	$ 6,435

Commitments And Contingencies_2

Commitments And Contingencies (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies [Abstract]
Rent expenses	$ 28	$ 27	$ 9
2019 required efficiency spending amount	$ 50
Percentage of full time employees represented by labor union	18.00%
Expiration date of collective bargaining agreement	Oct. 25, 2019

Commitments And Contingencies_3

Commitments And Contingencies (Schedule Of Future Miinimum Lease Payments Under Operating Leases) (Details) $ in Millions	Dec. 31, 2018USD ($)
Commitments and Contingencies [Abstract]
2,019	$ 29
2,020	22
2,021	20
2,022	15
2,023	8
Thereafter	5
Total future minimum lease payments	$ 99

Membership Interests (Narrative

Membership Interests (Narrative) (Details) - USD ($) $ in Millions	Feb. 19, 2019	Nov. 27, 2017	Dec. 31, 2018	Feb. 20, 2019
Subsequent Event [Line Items]
Regulatory capitalization ratio, debt		57.50%	60.00%
Regulatory capitalization ratio, equity		42.50%	40.00%
Regulatory capitalization ratio, debt			57.30%
Regulatory capitalization ratio, equity			42.70%
Members contribution			$ 284
Subsequent Event [Member]
Subsequent Event [Line Items]
Cash available for distribution under the capital structure restriction				$ 71
Members contribution	$ 70

Membership Interests (Schedule

Membership Interests (Schedule Of Distributions Paid) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Dividends Payable [Line Items]
Amount	$ 209	$ 237	$ 230
Payment One FY 2018 [Member]
Dividends Payable [Line Items]
Declaration Date	Oct. 24, 2018
Payment Date	Nov. 6, 2018
Amount	$ 179
Payment Two FY 2018 [Member]
Dividends Payable [Line Items]
Declaration Date	Jul. 25, 2018
Payment Date	Aug. 1, 2018
Amount	$ 30
Payment One FY 2017 [Member]
Dividends Payable [Line Items]
Declaration Date	Jul. 26, 2017
Payment Date	Aug. 1, 2017
Amount	$ 65
Payment Two FY 2017 [Member]
Dividends Payable [Line Items]
Declaration Date	Apr. 26, 2017
Payment Date	Apr. 27, 2017
Amount	$ 86
Payment Three FY 2017 [Member]
Dividends Payable [Line Items]
Declaration Date	Mar. 22, 2017
Payment Date	Mar. 24, 2017
Amount	$ 86

Membership Interests (Schedul_2

Membership Interests (Schedule Of Cash Capital Contributions) (Details) - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Nov. 30, 2018	Apr. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Members contribution			$ 284
Beneficial Owner [Member]
Related Party Transaction [Line Items]
Members contribution	$ 140	$ 144

Membership Interests (Schedul_3

Membership Interests (Schedule Of Changes To Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ (101)	$ (111)	$ (113)
Balance at end of period	(164)	(101)	(111)
Cash Flow Hedges - Interest Rate Swap [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(18)	(20)	(22)
Defined benefit pension plans (net of tax)
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges	2	2	2
Balance at end of period	(16)	(18)	(20)
Defined Benefit Pension and OPEB Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(83)	(91)	(91)
Defined benefit pension plans (net of tax)	(65)	8
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges
Balance at end of period	(148)	(83)	(91)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(101)	(111)	(113)
Defined benefit pension plans (net of tax)	(65)	8
Amounts reclassified from accumulated other comprehensive income (loss) and reported in interest expense and related charges	2	2	2
Balance at end of period	$ (164)	$ (101)	$ (111)

Employee Benefit Plans (Narrati

Employee Benefit Plans (Narrative) (Details)	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)item	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets		$ 1,691,000,000	$ 2,180,000,000
Earning period		3 years
Number of OPEB plans | item		2
Rolling period		4 years
Percentage of gains and losses		25.00%
Second pool representation of total investments, percentage		28.00%
Cash contributions		$ 123,000,000	180,000,000	$ 35,000,000
Thrift Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Cash contributions		$ 19,000,000	17,000,000	15,000,000
Oncor Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of corporate bonds | item		1,044
Pension And OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory assets		$ 1,018,000,000	1,215,000,000
Defined Benefit Pension Plans [Member] | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of net loss	$ 26,000,000
Amortization of prior service cost	0
Defined Benefit Pension Plans [Member] | Scenario, Forecast [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of net loss	3,000,000
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain		232,000,000	(201,000,000)
Net gain (loss)		(67,000,000)	11,000,000	(41,000,000)
Expected return on assets		120,000,000	115,000,000	122,000,000
Unfunded liability		(913,000,000)	(900,000,000)
Amortization of net loss		(49,000,000)	$ (45,000,000)	$ (41,000,000)
Expected funding, 2019		41,000,000
Expected funding, 2019 to 2023		$ 538,000,000
Discount rate		3.54%	4.05%	4.30%
Expected return on plan assets		5.11%	5.17%	5.54%
Cash contributions		$ 82,000,000	$ 149,000,000	$ 4,000,000
Pension Plan [Member] | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) in projected benefit obligation	(20,000,000)
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial gain		196,000,000	(154,000,000)
Net gain (loss)		177,000,000	(139,000,000)	(10,000,000)
Expected return on assets		9,000,000	8,000,000	9,000,000
Unfunded liability		$ (874,000,000)	(1,049,000,000)
Number of corporate bonds | item		377
Amortization of net loss		$ (57,000,000)	(32,000,000)	(35,000,000)
Amortization of prior service cost		(30,000,000)	$ (20,000,000)	$ (20,000,000)
Expected funding, 2019		35,000,000
Expected funding, 2019 to 2023		$ 179,000,000
Discount rate		3.73%	4.35%	4.60%
Expected return on plan assets		6.20%	6.10%	6.30%
Cash contributions		$ 41,000,000	$ 31,000,000	$ 31,000,000
OPEB Plan [Member] | Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Increase (decrease) in projected benefit obligation	38,000,000
Amortization of net loss	19,000,000
Amortization of prior service cost	19,000,000
OPEB Plan [Member] | Scenario, Forecast [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of net loss	0
Amortization of prior service cost	$ 0
Oncor Cash Balance Formula Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of employee's contribution match by employer		100.00%
Percentage of employee's contribution matched 100% by employer		6.00%
Oncor Traditional Retirement Plan Formula Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of employee's contribution match by employer		75.00%
Percentage of employee's contribution matched 100% by employer		6.00%

Employee Benefit Plans (Schedul

Employee Benefit Plans (Schedule Of Pension And OPEB Plan Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Total benefit costs	$ 147	$ 143	$ 138
Less amounts deferred principally as property or a regulatory asset	(69)	(98)	(100)
Net amounts recognized as operation and maintenance expense or other deductions	78	45	38
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total benefit costs	77	85	76
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total benefit costs	$ 70	$ 58	$ 62

Employee Benefit Plans (Pension

Employee Benefit Plans (Pension and OPEB Costs Recognized as Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components of net OPEB costs:
Net costs	$ 147	$ 143	$ 138
Pension Plan [Member]
Assumptions Used to Determine Net Periodic Pension and OPEB Costs:
Discount rate	3.54%	4.05%	4.30%
Expected return on plan assets	5.11%	5.17%	5.54%
Rate of compensation increase	4.46%	3.33%	3.29%
Components of net OPEB costs:
Service cost	$ 27	$ 24	$ 23
Interest cost	121	131	134
Expected return on assets	(120)	(115)	(122)
Amortization of net loss	49	45	41
Net costs	77	85	76
Other Changes in Plan Assets and Benefit Obligations Recognized as Regulatory Assets or in Other Comprehensive Income:
Net loss (gain)	67	(11)	41
Amortization of net loss	(49)	(45)	(41)
Plan amendments
Total recognized as regulatory assets or other comprehensive income	18	(56)
Net amounts recognized as expense	$ 95	$ 29	$ 76
OPEB Plan [Member]
Assumptions Used to Determine Net Periodic Pension and OPEB Costs:
Discount rate	3.73%	4.35%	4.60%
Expected return on plan assets	6.20%	6.10%	6.30%
Components of net OPEB costs:
Service cost	$ 8	$ 7	$ 7
Interest cost	44	47	49
Expected return on assets	(9)	(8)	(9)
Amortization of prior service cost (credit)	(30)	(20)	(20)
Amortization of net loss	57	32	35
Net costs	70	58	62
Other Changes in Plan Assets and Benefit Obligations Recognized as Regulatory Assets or in Other Comprehensive Income:
Net loss (gain)	(177)	139	10
Amortization of net loss	(57)	(32)	(35)
Plan amendments		(78)
Amortization of prior service cost (credit)	30	20	20
Total recognized as regulatory assets or other comprehensive income	(204)	49	(5)
Net amounts recognized as expense	$ (134)	$ 107	$ 57

Employee Benefit Plans (Assumpt

Employee Benefit Plans (Assumptions Used To Determine Benefit Obligations) (Details)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.18%	3.54%	4.05%
Rate of compensation increase	4.53%	4.46%	3.33%
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.41%	3.73%	4.35%

Employee Benefit Plans (Change

Employee Benefit Plans (Change In Project Benefit Obligations) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at beginning of year	$ 3,500	$ 3,307
Service cost	27	24	$ 23
Interest cost	121	131	134
Participant contributions
Plan amendments
Actuarial (gain) loss	(232)	201
Benefits paid	(175)	(163)
Annuity purchase	(79)
Projected benefit obligation at end of year	3,162	3,500	3,307
Accumulated benefit obligation at end of year	3,069	3,387
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at beginning of year	1,198	1,116
Service cost	8	7	7
Interest cost	44	47	49
Participant contributions	19	19
Plan amendments		(78)
Actuarial (gain) loss	(196)	154
Benefits paid	(67)	(67)
Annuity purchase
Projected benefit obligation at end of year	1,006	1,198	$ 1,116
Accumulated benefit obligation at end of year

Employee Benefit Plans (Chang_2

Employee Benefit Plans (Change In Plan Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 123	$ 180	$ 35
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of assets at beginning of year	2,600	2,287
Actual return (loss) on assets	(179)	327
Employer contributions	82	149	4
Participant contributions
Benefits paid	(175)	(163)
Annuity purchase	(79)
Fair value of assets at end of year	2,249	2,600	2,287
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of assets at beginning of year	149	143
Actual return (loss) on assets	(10)	23
Employer contributions	41	31	31
Participant contributions	19	19
Benefits paid	(67)	(67)
Annuity purchase
Fair value of assets at end of year	$ 132	$ 149	$ 143

Employee Benefit Plans (Funded

Employee Benefit Plans (Funded Status) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$ (3,162)	$ (3,500)	$ (3,307)
Fair value of assets at end of year	2,249	2,600	2,287
Funded status at end of year	(913)	(900)
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	(1,006)	(1,198)	(1,116)
Fair value of assets at end of year	132	149	$ 143
Funded status at end of year	$ (874)	$ (1,049)

Employee Benefit Plans (Amounts

Employee Benefit Plans (Amounts Recognized In Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive net loss	$ (164)	$ (101)	$ (111)	$ (113)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other current liabilities	(4)	(4)
Other noncurrent liabilities	(909)	(896)
Net liability recognized	(913)	(900)
Net loss	534	538
Net regulatory asset recognized	534	538
Accumulated other comprehensive net loss	147	124
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other current liabilities	(7)	(12)
Other noncurrent liabilities	(867)	(1,037)
Net liability recognized	(874)	(1,049)
Net loss	171	402
Prior service cost (credit)	(57)	(86)
Net regulatory asset recognized	114	316
Accumulated other comprehensive net loss	$ 1	$ 3

Employee Benefit Plans (Sched_2

Employee Benefit Plans (Schedule Of Assumed Health Care Cost Trend Rates) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Effect on accumulated postretirement obligation, 1-Percentage Point Increase	$ 124
Effect on accumulated postretirement obligation, 1-Percentage Point Decrease		$ (103)
Effect on postretirement benefits cost, 1-Percentage Point Increase	$ 7
Effect on postretirement benefits cost, 1-Percentage Point Decrease		$ (5)
Not Medicare Eligible [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care and prescription drug cost trend rate assumed for next year	7.60%	8.00%
Rate to which the cost trend is expected to decline (the ultimate trend rate)	4.50%	4.50%
Year that the rate reaches the ultimate trend rate	2,026	2,026
Medicare Eligible [Member]
Defined Benefit Plan Disclosure [Line Items]
Health care and prescription drug cost trend rate assumed for next year	8.70%	9.40%
Rate to which the cost trend is expected to decline (the ultimate trend rate)	4.50%	4.50%
Year that the rate reaches the ultimate trend rate	2,027	2,026

Employee Benefit Plans (Sched_3

Employee Benefit Plans (Schedule Of Projected Benefit Obligations And Accumulated Benefit Obligations In Excess Of Plan Assets Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Employee Benefit Plans [Abstract]
Projected benefit obligations	$ 3,162	$ 3,316
Accumulated benefit obligations	3,069	3,207
Plan assets	$ 2,249	$ 2,409

Employee Benefit Plans (Sched_4

Employee Benefit Plans (Schedule Of Target Asset Allocation Ranges By Asset Category) (Details)	Dec. 31, 2018
International Equities [Member] | Recoverable [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	13.00%
International Equities [Member] | Recoverable [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	21.00%
International Equities [Member] | Nonrecoverable [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	6.00%
International Equities [Member] | Nonrecoverable [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	12.00%
US Equities [Member] | Recoverable [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	16.00%
US Equities [Member] | Recoverable [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	24.00%
US Equities [Member] | Nonrecoverable [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	8.00%
US Equities [Member] | Nonrecoverable [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	14.00%
Real Estate [Member] | Recoverable [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	3.00%
Real Estate [Member] | Recoverable [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	7.00%
Credit Strategies [Member] | Recoverable [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	5.00%
Credit Strategies [Member] | Recoverable [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	10.00%
Credit Strategies [Member] | Nonrecoverable [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	5.00%
Credit Strategies [Member] | Nonrecoverable [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	9.00%
Fixed Income [Member] | Recoverable [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	45.00%
Fixed Income [Member] | Recoverable [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	55.00%
Fixed Income [Member] | Nonrecoverable [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	68.00%
Fixed Income [Member] | Nonrecoverable [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	78.00%

Employee Benefit Plans (Sched_5

Employee Benefit Plans (Schedule Of Assets Fair Value Measured On Recurring Basis) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	$ 2,249	$ 2,600	$ 2,287
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	132	149	$ 143
Fair Value, Inputs, Level 1 [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	409	506
Fair Value, Inputs, Level 1 [Member] | OPEB Plan [Member] | Accounting Standards Update 2015-07 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	86	97
Fair Value, Inputs, Level 1 [Member] | Interest-bearing Cash [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	15	1
Fair Value, Inputs, Level 1 [Member] | US Equities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	170	235
Fair Value, Inputs, Level 1 [Member] | US Equities [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	21	35
Fair Value, Inputs, Level 1 [Member] | International Equities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	239	271
Fair Value, Inputs, Level 1 [Member] | International Equities [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	22	33
Fair Value, Inputs, Level 1 [Member] | Other [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	28	28
Fair Value, Inputs, Level 2 [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	1,111	1,389
Fair Value, Inputs, Level 2 [Member] | OPEB Plan [Member] | Accounting Standards Update 2015-07 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	30	35
Fair Value, Inputs, Level 2 [Member] | Interest-bearing Cash [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets		11
Fair Value, Inputs, Level 2 [Member] | Interest-bearing Cash [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets		1
Fair Value, Inputs, Level 2 [Member] | US Equities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	2	2
Fair Value, Inputs, Level 2 [Member] | Corporate Bond Securities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	930	1,081
Fair Value, Inputs, Level 2 [Member] | Corporate Bond Securities [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	26	30
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	110	251
Fair Value, Inputs, Level 2 [Member] | US Treasury Securities [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	3	3
Fair Value, Inputs, Level 2 [Member] | Other [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	69	44
Fair Value, Inputs, Level 2 [Member] | Other [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	1	1
Fair Value, Inputs, Level 3 [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	3	3
Fair Value, Inputs, Level 3 [Member] | Real Estate [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	3	3
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	1,523	1,898
Fair Value, Inputs, Level 1, 2 and 3 [Member] | OPEB Plan [Member] | Accounting Standards Update 2015-07 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	116	132
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Interest-bearing Cash [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets		11
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Interest-bearing Cash [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	15	2
Fair Value, Inputs, Level 1, 2 and 3 [Member] | US Equities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	172	237
Fair Value, Inputs, Level 1, 2 and 3 [Member] | US Equities [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	21	35
Fair Value, Inputs, Level 1, 2 and 3 [Member] | International Equities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	239	271
Fair Value, Inputs, Level 1, 2 and 3 [Member] | International Equities [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	22	33
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Corporate Bond Securities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	930	1,081
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Corporate Bond Securities [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	26	30
Fair Value, Inputs, Level 1, 2 and 3 [Member] | US Treasury Securities [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	110	251
Fair Value, Inputs, Level 1, 2 and 3 [Member] | US Treasury Securities [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	3	3
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Other [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	69	44
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Other [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	29	29
Fair Value, Inputs, Level 1, 2 and 3 [Member] | Real Estate [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	3	3
NAV [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	726	702
NAV [Member] | OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total fair value of plan assets	$ 16	$ 17

Employee Benefit Plans (Sched_6

Employee Benefit Plans (Schedule Of Expected Long-Term Rate Of Return On Assets Assumptions) (Details)	12 Months Ended
	Dec. 31, 2018
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	5.64%
Pension Plan [Member] | International Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	7.70%
Pension Plan [Member] | US Equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	6.60%
Pension Plan [Member] | Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	5.40%
Pension Plan [Member] | Credit Strategies [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	5.58%
Pension Plan [Member] | Fixed Income [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	4.30%
Pension Plan [Member] | Oncor Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	4.91%
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	6.19%
OPEB Plan [Member] | 401(h) Accounts [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	6.63%
OPEB Plan [Member] | Life Insurance VEBA [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	6.08%
OPEB Plan [Member] | Union VEBA [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	6.08%
OPEB Plan [Member] | Non-union VEBA [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	2.90%
OPEB Plan [Member] | Vistra Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return	5.29%

Employee Benefit Plans (Sched_7

Employee Benefit Plans (Schedule Of Contributions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Total contributions	$ 123	$ 180	$ 35
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions	82	149	4
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Total contributions	$ 41	$ 31	$ 31

Employee Benefit Plans (Sched_8

Employee Benefit Plans (Schedule Of Estimated Future Benefit Payments) (Details) $ in Millions	Dec. 31, 2018USD ($)
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
2,019	$ 183
2,020	187
2,021	192
2,022	196
2,023	200
2024-28	1,031
OPEB Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
2,019	53
2,020	56
2,021	58
2,022	61
2,023	63
2024-28	$ 320

Stock-Based Compensation (Narra

Stock-Based Compensation (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	0
SARs Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend accrual compensation expense	$ 15
SARs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Recognized dividend accretion and interest	$ 4	$ 1	$ 1

Related-Party Transactions (Nar

Related-Party Transactions (Narrative) (Details) - USD ($) $ in Millions	Mar. 08, 2018	Oct. 02, 2016	Jan. 01, 2016	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Related Party Transaction [Line Items]
Transformer maintenance revenue				$ 4,101	$ 3,958	[1]	$ 3,920	[1]
Wholesale transmission service				$ 962	929	[1]	894	[1]
Sponsor Group [Member]
Related Party Transaction [Line Items]
Equity in existing vendor	16.00%
TCEH [Member]
Related Party Transaction [Line Items]
Revenues from electricity delivery fees		$ 715	$ 715
EFH Corp [Member]
Related Party Transaction [Line Items]
Administrative and services costs							1
Shared facilities expense							3
Shared facilities payments received							1
Sponsor Group [Member]
Related Party Transaction [Line Items]
Cash payments to vendors	$ 35				219		188
Trade payables related parties					7
Sponsor Group [Member] | Capitalized [Member]
Related Party Transaction [Line Items]
Cash payments to vendors	33				210		180
Sponsor Group [Member] | Operating And Maintenance Expense [Member]
Related Party Transaction [Line Items]
Cash payments to vendors	$ 2				$ 9		$ 8
[1]	As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.

Related-Party Transactions (Sch

Related-Party Transactions (Schedule Of Trade Accounts And Other Receivables From Related Parties) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Federal income taxes payable (receivable)		$ (26)
Texas margin taxes payable	$ 26	21
Net payable (receivable)	26	(5)
Texas [Member]
Related Party Transaction [Line Items]
Texas margin taxes payable	21	21
Federal [Member]
Related Party Transaction [Line Items]
Federal income taxes payable (receivable)	5	(26)
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	21
EFH Corp [Member] | Federal [Member]
Related Party Transaction [Line Items]
Federal income taxes payable (receivable)	4	(21)
Texas Transmission Investment LLC [Member]
Related Party Transaction [Line Items]
Net payable (receivable)	1	(5)
Texas Transmission Investment LLC [Member] | Federal [Member]
Related Party Transaction [Line Items]
Federal income taxes payable (receivable)	$ 1	$ (5)

Related-Party Transactions (S_2

Related-Party Transactions (Schedule Of Related Party Transactions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Federal income taxes	$ 50	$ (114)
Texas margin taxes	21	20
Total payments (receipts)	71	(94)
EFH Corp [Member]
Related Party Transaction [Line Items]
Federal income taxes	(19)	(102)
Texas margin taxes		20	$ 20
Total payments (receipts)	(19)	(82)	$ 20
Texas Transmission Investment LLC [Member]
Related Party Transaction [Line Items]
Federal income taxes	10	(12)
Total payments (receipts)	$ 10	$ (12)

Supplementary Financial Infor_3

Supplementary Financial Information (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2004	Dec. 31, 2003
Supplemental Financial Information [Line Items]
Face value of life insurance policies	$ 157,000,000	$ 162,000,000
Net cash surrender values	$ 87,000,000	$ 84,000,000
Depreciation expense as percentage of average depreciable property	2.80%	3.40%	3.50%
Aggregate amortization expenses	$ 50,000,000	$ 57,000,000	$ 61,000,000
Goodwill	$ 4,064,000,000	$ 4,064,000,000
Bondco [Member]
Supplemental Financial Information [Line Items]
Principal amount of transition bonds issued				$ 1,300,000,000	$ 1,300,000,000
Financial support			$ 0
Trade Accounts Receivable [Member] | Nonaffiliated REP [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage	13.00%	12.00%
Trade Accounts Receivable [Member] | Second Nonaffiliated REP [Member]
Supplemental Financial Information [Line Items]
Concentration risk percentage	10.00%	10.00%
Land Easements [Member]
Supplemental Financial Information [Line Items]
Weighted average remaining useful life	82 years
Capitalized Software [Member]
Supplemental Financial Information [Line Items]
Weighted average remaining useful life	9 years

Supplementary Financial Infor_4

Supplementary Financial Information (Schedule Of Other Income And (Deductions)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Supplementary Financial Information [Abstract]
Professional fees	$ (12)	$ (15)		$ (15)
Sempra Acquisition related costs	(12)
Recoverable pension and OPEB - non-service costs	(53)	(31)		(28)
Non-recoverable pension and OPEB (Note 10)	(6)	(5)		(2)
Interest income	1	6		2
Other	(2)	(1)
Total other income and (deductions) - net	$ (84)	$ (46)	[1]	$ (43)	[1]
[1]	As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.

Supplementary Financial Infor_5

Supplementary Financial Information (Schedule Of Interest Expense And Related Charges) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Supplementary Financial Information [Abstract]
Interest	$ 358	$ 351		$ 341
Amortization of debt issuance costs and discounts	6	3		3
Less allowance for funds used during construction — capitalized interest portion	(13)	(12)		(8)
Total interest expense and related charges	$ 351	$ 342	[1]	$ 336	[1]
[1]	As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.

Supplementary Financial Infor_6

Supplementary Financial Information (Schedule Of Trade Accounts And Other Receivables) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Supplementary Financial Information [Abstract]
Gross trade accounts and other receivables	$ 562	$ 638
Allowance for uncollectible accounts	(3)	(3)
Trade accounts receivable - net	$ 559	$ 635

Supplementary Financial Infor_7

Supplementary Financial Information (Summary of Investments And Other Property) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Supplementary Financial Information [Abstract]
Assets related to employee benefit plans, including employee savings programs	$ 108	$ 111
Land	12	2
Total investments and other property	$ 120	$ 113

Supplementary Financial Infor_8

Supplementary Financial Information (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property Plant and Equipment [Line Items]
Total assets in service	$ 23,170	$ 21,717
Less accumulated depreciation and amortization	7,513	7,255
Net of accumulated depreciation and amortization	15,657	14,462
Construction work in progress	417	402
Held for future use	16	15
Property, plant and equipment - net	16,090	14,879
Distribution [Member]
Property Plant and Equipment [Line Items]
Total assets in service	$ 13,105	12,467
Composite depreciation rate	2.80%
Avg. life	35 years 1 month 6 days
Transmission [Member]
Property Plant and Equipment [Line Items]
Total assets in service	$ 8,568	7,870
Composite depreciation rate	2.90%
Avg. life	34 years 4 months 24 days
Other Assets [Member]
Property Plant and Equipment [Line Items]
Total assets in service	$ 1,497	$ 1,380
Composite depreciation rate	6.90%
Avg. life	14 years 7 months 6 days

Supplementary Financial Infor_9

Supplementary Financial Information (Schedule Of Intangible Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,251	$ 1,132
Accumulated Amortization	486	435
Net	765	697
Land Easements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	464	453
Accumulated Amortization	101	96
Net	363	357
Capitalized Software [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	787	679
Accumulated Amortization	385	339
Net	$ 402	$ 340

Supplementary Financial Info_10

Supplementary Financial Information (Schedule Of Estimated Aggregate Amortization Expenses) (Details) $ in Millions	Dec. 31, 2018USD ($)
Supplementary Financial Information [Abstract]
2,019	$ 50
2,020	49
2,021	49
2,022	49
2,023	$ 49

Supplementary Financial Info_11

Supplementary Financial Information (Schedule Of Employee Benefit Obligations And Other) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Supplementary Financial Information [Abstract]
Retirement plans and other employee benefits	$ 1,858	$ 2,035
Investment tax credits	8	10
Other	77	57
Total employee benefit obligations and other	$ 1,943	$ 2,102

Supplementary Financial Info_12

Supplementary Financial Information (Schedule Of Supplemental Cash Flow Information) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplementary Financial Information [Abstract]
Interest	$ 368	$ 345	$ 336
Less capitalized interest	(13)	(12)	(8)
Interest payments (net of amounts capitalized)	355	333	328
Federal	50	(114)
State	21	20	20
Total payments (receipts) in lieu of income taxes	71	(94)	20
Noncash Sharyland Asset Exchange costs		383
Noncash construction expenditures	$ 174	$ 129	$ 122

Supplementary Financial Info_13

Supplementary Financial Information (Schedule Of Quarterly Information) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	[1]	Dec. 31, 2016	[1]
Supplementary Financial Information [Abstract]
Operating revenues (Note 4)	$ 995	$ 1,095	$ 1,021	$ 990	$ 991	$ 1,068	$ 964	$ 935
Operating income	206	293	244	202	190	252	202	164	$ 945	$ 808		$ 795
Net income	$ 119	$ 194	$ 143	$ 89	$ 77	$ 157	$ 112	$ 73	$ 545	$ 419		$ 431
[1]	As adjusted for the retrospective adoption of ASU 2017-07, as discussed in Note 1.

Acquisition Activity (Narrative

Acquisition Activity (Narrative) (Details) $ / shares in Units, $ in Millions	Oct. 18, 2018USD ($)$ / shares	Jul. 21, 2017USD ($)mikW	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Sep. 30, 2018USD ($)
Business Acquisition [Line Items]
Cash paid				$ 25
Sharyland Merger Agreement [Member]
Business Acquisition [Line Items]
Purchase price		$ 408
Transmission of assets		383
Cash paid		$ 25
Number of assets transferred in circuit miles | mi		517
Power of number of transmission lines transferred | kW		345
InfraREIT [Member]
Business Acquisition [Line Items]
Price per share of common stock to stockholders and limited partners | $ / shares	$ 21
Purchase price	$ 1,275
Management agreement termination fee	$ 40.5
Outstanding debt acquired					$ 945
InfraREIT [Member] | Sempra Energy [Member]
Business Acquisition [Line Items]
Partner capital contribution for business combination			$ 1,330