Centerpoint Energy Houston Electric 10-K 28 Feb 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Jun. 30, 2016
Document Information [Line Items]
Entity Registrant Name	CENTERPOINT ENERGY HOUSTON ELECTRIC LLC
Entity Central Index Key	48,732
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding	1,000
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float		$ 0

STATEMENTS OF CONSOLIDATED INCO

STATEMENTS OF CONSOLIDATED INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues	$ 3,059	$ 2,846	$ 2,846
Expenses:
Operation and maintenance	1,363	1,311	1,258
Depreciation and amortization	838	705	768
Taxes other than income taxes	231	222	224
Total	2,432	2,238	2,250
Operating Income	627	608	596
Other Income (Expense):
Interest and other finance charges	(126)	(118)	(109)
Interest on Securitization Bonds	(91)	(105)	(118)
Other, net	15	21	14
Total	(202)	(202)	(213)
Income Before Income Taxes	425	406	383
Income tax expense	149	145	131
Net Income	$ 276	$ 261	$ 252

STATEMENTS OF COMPREHENSIVE INC

STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income	$ 276	$ 261	$ 252
Other comprehensive income:
Net deferred gain from cash flow hedges (net of tax of $-0-, $-0-, and $-0-)	1	0	0
Total	1	0	0
Comprehensive income	$ 277	$ 261	$ 252

STATEMENTS OF COMPREHENSIVE IN4

STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tax expense (benefit) on net deferred gain (loss) from cash flow hedges	$ 0	$ 0	$ 0

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents ($340 and $264 related to VIEs, respectively)	$ 341	$ 264
Accounts and notes receivable, net ($52 and $64 related to VIEs, respectively), less bad debt reserve of $1 and $1, respectively	225	234
Accounts and notes receivable—affiliated companies	101	16
Accrued unbilled revenues	106	96
Inventory	134	133
Taxes receivable	6	59
Other ($40 and $35 related to VIEs, respectively)	66	63
Total current assets	979	865
Property, Plant and Equipment, net	7,397	6,933
Other Assets:
Regulatory assets ($1,919 and $2,373 related to VIEs, respectively)	1,793	2,211
Other	42	16
Total other assets	1,835	2,227
Total Assets	10,211	10,025
Current Liabilities:
Current portion of VIE Securitization Bonds long-term debt	411	391
Accounts payable	145	153
Accounts and notes payable—affiliated companies	88	348
Taxes accrued	106	100
Interest accrued	68	70
Other	90	69
Total current liabilities	908	1,131
Other Liabilities:
Deferred income taxes, net	2,003	2,032
Benefit obligations	148	192
Regulatory liabilities	530	542
Other	51	59
Total other liabilities	2,732	2,825
Long-Term Debt, net:
VIE Securitization Bonds, net	1,867	2,276
Other long-term debt, net	2,587	2,192
Total long-term debt, net	4,454	4,468
Commitments and Contingencies (Note 10)
Member’s Equity:
Common stock	0	0
Paid-in capital	1,696	1,322
Retained earnings	420	279
Accumulated other comprehensive income	1	0
Total member’s equity	2,117	1,601
Total Liabilities and Member’s Equity	$ 10,211	$ 10,025

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Cash and cash equivalents ($340 and $264 related to VIEs, respectively)	$ 341	$ 264
Allowance for Doubtful Accounts Receivable, Current	1	1
Accounts and notes receivable, net ($52 and $64 related to VIEs, respectively), less bad debt reserve of $1 and $1, respectively	225	234
Other ($40 and $35 related to VIEs, respectively)	66	63
Regulatory assets ($1,919 and $2,373 related to VIEs, respectively)	1,793	2,211
Variable Interest Entity, Primary Beneficiary [Member]
Cash and cash equivalents ($340 and $264 related to VIEs, respectively)	340	264
Accounts and notes receivable, net ($52 and $64 related to VIEs, respectively), less bad debt reserve of $1 and $1, respectively	52	64
Other ($40 and $35 related to VIEs, respectively)	40	35
Regulatory assets ($1,919 and $2,373 related to VIEs, respectively)	$ 1,919	$ 2,373

STATEMENTS OF CONSOLIDATED CASH

STATEMENTS OF CONSOLIDATED CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash Flows from Operating Activities:
Net income	$ 276	$ 261	$ 252
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	838	705	768
Amortization of deferred financing costs	14	15	16
Deferred income taxes	(34)	18	(24)
Changes in other assets and liabilities:
Accounts and notes receivable, net	(1)	3	15
Accounts receivable/payable–affiliated companies	63	(89)	37
Inventory	(1)	(7)	(21)
Accounts payable	(4)	0	(3)
Taxes receivable	53	44	(103)
Interest and taxes accrued	4	(9)	(40)
Net regulatory assets and liabilities	(110)	3	(28)
Other current assets	2	(1)	(2)
Other current liabilities	21	(40)	(19)
Other assets	(8)	(7)	11
Other liabilities	(4)	(1)	5
Other, net	1	0	(6)
Net cash provided by operating activities	1,110	895	858
Cash Flows from Investing Activities:
Capital expenditures	(862)	(929)	(804)
Decrease (increase) in notes receivable–affiliated companies	(96)	107	(107)
Decrease (increase) in restricted cash of Bond Companies	(5)	12	(7)
Other, net	(1)	1	1
Net cash used in investing activities	(964)	(809)	(917)
Cash Flows from Financing Activities:
Proceeds from long-term debt	600	200	600
Payments of long-term debt	(590)	(372)	(537)
Dividend to parent	(135)	(252)	0
Increase (decrease) in notes payable–affiliated companies	(312)	312	(3)
Cash paid for debt retirements	0	0	(1)
Debt issuance costs	(6)	0	(7)
Contribution from parent	374	0	90
Net cash provided by (used in) financing activities	(69)	(112)	142
Net Increase (Decrease) in Cash and Cash Equivalents	77	(26)	83
Cash and Cash Equivalents at Beginning of the Year	264	290	207
Cash and Cash Equivalents at End of the Year	341	264	290
Cash Payments:
Interest, net of capitalized interest	209	213	215
Income taxes	128	81	296
Non-cash transactions:
Accounts payable related to capital expenditures	$ 65	$ 69	$ 64

STATEMENTS OF CONSOLIDATED MEMB

STATEMENTS OF CONSOLIDATED MEMBER'S EQUITY - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]	AOCI Attributable to Parent [Member]
Shares, Outstanding at Dec. 31, 2013		1,000
Balance at Dec. 31, 2013		$ 0	$ 1,232	$ 18
Contribution from parent			90
Net income	$ 252			252
Dividend to parent				0
Balance at Dec. 31, 2014	1,592	$ 0	1,322	270	$ 0	$ 0
Shares, Outstanding at Dec. 31, 2014		1,000
Contribution from parent			0
Net income	261			261
Dividend to parent				(252)
Balance at Dec. 31, 2015	1,601	$ 0	1,322	279	0	0
Shares, Outstanding at Dec. 31, 2015		1,000
Contribution from parent			374
Net income	276			276
Dividend to parent				(135)
Balance at Dec. 31, 2016	$ 2,117	$ 0	$ 1,696	$ 420	$ 1	$ 1
Shares, Outstanding at Dec. 31, 2016		1,000

Background

Background	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Background [Text Block]	Background Houston Electric is an indirect, wholly-owned subsidiary of CenterPoint Energy, Inc., a public utility holding company. Houston Electric provides electric transmission and distribution services to REPs serving over 2.4 million metered customers in the Texas Gulf Coast area that includes the city of Houston. As of December 31, 2016 , Houston Electric had the following subsidiaries: Bond Company II, Bond Company III, Restoration Bond Company and Bond Company IV. Houston Electric consists of a single reportable business segment: Electric Transmission & Distribution.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	Summary of Significant Accounting Policies (a) Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. (b) Principles of Consolidation The accounts of Houston Electric and its wholly-owned subsidiaries are included in Houston Electric’s consolidated financial statements. All intercompany transactions and balances are eliminated in consolidation. As of December 31, 2016 , Houston Electric had VIEs consisting of the Bond Companies, which it consolidates. The consolidated VIEs are wholly-owned, bankruptcy remote special purpose entities that were formed specifically for the purpose of securitizing transition and system restoration related property. Creditors of Houston Electric have no recourse to any assets or revenues of the Bond Companies. The bonds issued by these VIEs are payable only from and secured by transition and system restoration property and the bondholders have no recourse to the general credit of Houston Electric. (c) Revenues Houston Electric records revenue for electricity delivery under the accrual method and these revenues are recognized upon delivery to customers. Electricity deliveries not billed by month-end are accrued based on actual AMS data, daily supply volumes and applicable rates. (d) Long-lived Assets and Intangibles Houston Electric records property, plant and equipment at historical cost. Houston Electric expenses repair and maintenance costs as incurred. Houston Electric periodically evaluates long-lived assets, including property, plant and equipment, and specifically identifiable intangibles, when events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. The determination of whether an impairment has occurred is based on an estimate of undiscounted cash flows attributable to the assets compared to the carrying value of the assets. (e) Regulatory Assets and Liabilities Houston Electric applies the guidance for accounting for regulated operations. Houston Electric’s rate-regulated subsidiaries may collect revenues subject to refund pending final determination in rate proceedings. In connection with such revenues, estimated rate refund liabilities are recorded which reflect management’s current judgment of the ultimate outcomes of the proceedings. Houston Electric had current regulatory liabilities of $7 million and $2 million as of December 31, 2016 and 2015, respectively, included in other current liabilities in its Consolidated Balance Sheets. Houston Electric recognizes removal costs as a component of depreciation expense in accordance with regulatory treatment. As of December 31, 2016 and 2015 , these removal costs of $345 million and $350 million , respectively, are classified as regulatory liabilities in Houston Electric’s Consolidated Balance Sheets. In addition, a portion of the amount of removal costs that relate to AROs has been reclassified from a regulatory liability to an asset retirement liability in accordance with accounting guidance for AROs. (f) Depreciation and Amortization Expense Depreciation is computed using the straight-line method based on economic lives or a regulatory-mandated recovery period. Transition and system restoration property is being amortized over the expected life of the Securitization Bonds ( 12 to 14 years ), based on estimated revenue from transition or system restoration charges, interest accruals and other expenses. Other amortization expense includes amortization of regulatory assets and other intangibles. (g) Capitalization of Interest and AFUDC Interest and AFUDC are capitalized as a component of projects under construction and are amortized over the assets’ estimated useful lives once the assets are placed in service. AFUDC represents the composite interest cost of borrowed funds and a reasonable return on the equity funds used for construction. Although AFUDC increases both utility plant and earnings, it is realized in cash when the assets are included in rates. During 2016 , 2015 and 2014 , Houston Electric capitalized interest and AFUDC of $6 million , $8 million and $10 million , respectively. During 2016 , 2015 and 2014 , Houston Electric recorded AFUDC equity of $6 million , $12 million and $14 million , respectively, which is included in Other Income in its Statements of Consolidated Income. (h) Income Taxes Houston Electric is a member of the U.S. federal consolidated income tax return of CenterPoint Energy. Houston Electric reports its income tax provision on a separate entity basis pursuant to a tax sharing agreement with CenterPoint Energy. Houston Electric uses the asset and liability method of accounting for deferred income taxes. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is established against deferred tax assets for which management believes realization is not considered to be more likely than not. Houston Electric recognizes interest and penalties as a component of income tax expense. Current federal and certain state income taxes are payable to or receivable from CenterPoint Energy. (i) Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount and do not bear interest. It is the policy of management to review the outstanding accounts receivable monthly, as well as the bad debt write-offs experienced in the past, and establish an allowance for doubtful accounts. Account balances are charged off against the allowance when management determines it is probable the receivable will not be recovered. The provision for doubtful accounts in Houston Electric’s Statements of Consolidated Income for 2016 , 2015 and 2014 was less than $1 million , less than $1 million and $3 million , respectively. (j) Inventory Inventory consists principally of materials and supplies and is valued at the lower of average cost or market. Materials and supplies are recorded to inventory when purchased and subsequently charged to expense or capitalized to plant when installed. (k) Statements of Consolidated Cash Flows For purposes of reporting cash flows, Houston Electric considers cash equivalents to be short-term, highly-liquid investments with maturities of three months or less from the date of purchase. In connection with the issuance of securitization bonds, Houston Electric was required to establish restricted cash accounts to collateralize the bonds that were issued in these financing transactions. These restricted cash accounts are not available for withdrawal until the maturity of the bonds and are not included in cash and cash equivalents. These restricted cash accounts of $40 million and $35 million as of December 31, 2016 and 2015 , respectively, are included in other current assets in Houston Electric’s Consolidated Balance Sheets. For additional information regarding Securitization Bonds, see Note 8 . Cash and cash equivalents included $340 million and $264 million as of December 31, 2016 and 2015 , respectively, that was held by the Bond Companies solely to support servicing the Securitization Bonds. (l) New Accounting Pronouncements In February 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis (ASU 2015-02). ASU 2015 -02 changes the analysis that reporting organizations must perform to evaluate whether they should consolidate certain legal entities, such as limited partnerships. The changes include, among others, modification of the evaluation of whether limited partnerships and similar legal entities are VIEs or voting interest entities and elimination of the presumption that a general partner should consolidate a limited partnership. ASU 2015-02 does not amend the related party guidance for situations in which power is shared between two or more entities that hold interests in a VIE. Houston Electric adopted ASU 2015-02 on January 1, 2016, which did not have a material impact on its financial position, results of operations, cash flows and disclosures. In April 2015, the FASB issued ASU No. 2015-03, Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Cost (ASU 2015-03) . ASU 2015-03 requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by ASU 2015-03. Houston Electric adopted ASU 2015-03 retrospectively on January 1, 2016, which resulted in a reduction of both other long-term assets and total long-term debt on its Consolidated Balance Sheets. Houston Electric had debt issuance costs, excluding amounts related to credit facility arrangements, of $23 million and $21 million as a reduction to long-term debt on its Consolidated Balance Sheets as of December 31, 2016 and 2015 , respectively. In May 2015, the FASB issued ASU No. 2015-07, Fair Value Measurement (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) (ASU 2015-07). ASU 2015-07 removes the requirement to categorize within the fair value hierarchy investments for which fair values are measured at NAV using the practical expedient. Entities will be required to disclose the fair value of investments measured using the NAV practical expedient so that financial statement users can reconcile amounts reported in the fair value hierarchy table to amounts reported on the balance sheet. Houston Electric retrospectively adopted ASU 2015-07 on January 1, 2016, which impacts its employee benefit plan disclosures. See Note 5 for the impacts on the employee benefit plan disclosures. This standard did not have an impact on Houston Electric’s financial position, results of operations or cash flows. In September 2015, the FASB issued ASU No. 2015-16, Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments (ASU 2015-16). ASU 2015-16 eliminates the requirement for an acquirer in a business combination to account for measurement-period adjustments retrospectively. Instead, an acquirer would recognize a measurement-period adjustment during the period in which the amount of the adjustment is determined. Houston Electric prospectively adopted ASU 2015-16 on January 1, 2016, which did not have an impact on its financial position, results of operations or cash flows. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01). ASU 2016-01 requires equity investments that do not result in consolidation and are not accounted for under the equity method to be measured at fair value and to recognize any changes in fair value in net income unless the investments qualify for the new practicability exception. It does not change the guidance for classifying and measuring investments in debt securities and loans. ASU 2016-01 also changes certain disclosure requirements and other aspects related to recognition and measurement of financial assets and financial liabilities. ASU 2016-01 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017. As of the first reporting period in which the guidance is adopted, a cumulative-effect adjustment to beginning retained earnings will be made, with two features that will be adopted prospectively. Houston Electric is currently assessing the impact that this standard will have on its financial position, results of operations, cash flows and disclosures. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (ASU 2016-02). ASU 2016-02 provides a comprehensive new lease model that requires lessees to recognize assets and liabilities for most leases and would change certain aspects of lessor accounting. ASU 2016-02 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. A modified retrospective adoption approach is required. Houston Electric is currently assessing the impact that this standard will have on its financial position, results of operations, cash flows and disclosures. In 2016, the FASB issued ASUs which amended ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) . ASU 2014-09, as amended, provides a comprehensive new revenue recognition model that requires revenue to be recognized in a manner that depicts the transfer of goods or services to a customer at an amount that reflects the consideration expected to be received in exchange for those goods or services. Early adoption is not permitted, and entities have the option of using either a full retrospective or a modified retrospective adoption approach. Houston Electric is currently evaluating its revenue streams under these ASUs and has not yet identified any significant changes as the result of these new standards. A substantial amount of Houston Electric’s revenues are tariff based, which we do not anticipate significant impact from these ASUs. Houston Electric is considering the impacts of the new guidance on its ability to recognize revenue for certain contracts when collectability is uncertain and its accounting for contributions in aid of construction. Houston Electric expects to adopt these ASUs on January 1, 2018 and is evaluating the method of adoption. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (ASU 2016-15). ASU 2016-15 provides clarifying guidance on the classification of certain cash receipts and payments in the statement of cash flows and eliminates the variation in practice related to such classifications. ASU 2016-15 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. A retrospective adoption approach is required. Houston Electric is currently assessing the impact that this standard will have on its statement of cash flows. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (ASU 2016-18). ASU 2016-18 requires a statement of cash flows explain the change during the period in the total of cash, cash equivalents, restricted cash and restricted cash equivalents. As a result the statement of cash flows will no longer present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents. When cash, cash equivalents, restricted cash and restricted cash equivalents are presented in more than one line item on the balance sheet, the new guidance requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet. ASU 2016-18 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. A retrospective adoption approach is required. Houston Electric is currently assessing the impact that this standard will have on its statement of cash flows and disclosures. In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business (ASU 2017-01). ASU 2017-01 revises the definition of a business. If substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets, then under ASU 2017-01, the asset or group of assets is not a business. The guidance also requires a business to include at least one substantive process and narrows the definition of outputs to be more closely aligned with how outputs are described in ASC 606. ASU 2017-01 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted in certain circumstances. A prospective adoption approach is required. ASU 2017-01 could have a potential impact on Houston Electric’s accounting for future acquisitions. Management believes that other recently issued standards, which are not yet effective, will not have a material impact on Houston Electric’s consolidated financial position, results of operations or cash flows upon adoption. (m) Other Current Liabilities Included in other current liabilities on the Consolidated Balance Sheets as of December 31, 2016 and 2015 was $17 million and $12 million , respectively, of customer deposits primarily held by the Bond Companies. (n) Environmental Costs Houston Electric expenses or capitalizes environmental expenditures, as appropriate, depending on their future economic benefit. Houston Electric expenses amounts that relate to an existing condition caused by past operations that do not have future economic benefit. Houston Electric records undiscounted liabilities related to these future costs when environmental assessments and/or remediation activities are probable and the costs can be reasonably estimated.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment [Text Block]	Property, Plant and Equipment (a) Property, Plant and Equipment Property, plant and equipment includes the following: Weighted Average Useful December 31, Lives (in years) 2016 2015 (in millions) Transmission 44 $ 2,402 $ 2,196 Distribution 31 6,965 6,556 Other 14 1,473 1,390 Total 10,840 10,142 Accumulated depreciation 3,443 3,209 Property, plant and equipment, net $ 7,397 $ 6,933 (b) Depreciation and Amortization The following table presents depreciation and amortization expense for 2016 , 2015 and 2014 : Year Ended December 31, 2016 2015 2014 (in millions) Depreciation expense $ 349 $ 316 $ 295 Amortization of securitized regulatory assets 455 365 441 Other amortization 34 24 32 Total depreciation and amortization $ 838 $ 705 $ 768 (c) AROs A reconciliation of the changes in the ARO liability is as follows: December 31, 2016 2015 (in millions) Beginning balance $ 37 $ 36 Accretion expense 1 1 Revisions in estimates of cash flows (5 ) — Ending balance $ 33 $ 37 Houston Electric recorded AROs associated with the removal of asbestos and asbestos-containing material in its buildings, including substation building structures. Houston Electric also recorded AROs relating to treated wood poles for electric distribution, distribution transformers containing PCB (also known as Polychlorinated Biphenyl), and underground fuel storage tanks. The estimates of future liabilities were developed using historical information, and where available, quoted prices from outside contractors. The decrease of $5 million in the ARO from the revision in estimates in 2016 is primarily attributable to the reduction in disposal costs. There were no material additions or settlements during the years ended December 31, 2016 and 2015 .

Regulatory Matters

Regulatory Matters	12 Months Ended
	Dec. 31, 2016
Regulatory Assets and Liabilities, Other Disclosures [Abstract]
Regulatory Matters [Text Block]	Regulatory Matters The following is a list of regulatory assets/liabilities reflected on Houston Electric’s Consolidated Balance Sheets as of December 31, 2016 and 2015 : December 31, 2016 2015 (in millions) Securitized regulatory assets $ 1,919 $ 2,373 Unrecognized equity return (1) (329 ) (393 ) Unamortized loss on reacquired debt 84 93 Pension and postretirement-related regulatory asset 34 50 Other long-term regulatory assets (2) 85 88 Total regulatory assets 1,793 2,211 Estimated removal costs 345 350 Other long-term regulatory liabilities 185 192 Total regulatory liabilities 530 542 Total regulatory assets and liabilities, net $ 1,263 $ 1,669 (1) The unrecognized allowed equity return will be recognized as it is recovered in rates through 2024. During the years ended December 31, 2016 , 2015 and 2014 , Houston Electric recognized approximately $64 million , $49 million and $68 million , respectively, of the allowed equity return. The timing of Houston Electric’s recognition of the allowed equity return will vary each period based on amounts actually collected during the period. The actual amounts recovered for the allowed equity return are reviewed and adjusted at least annually by the PUCT to correct any over-collections or under-collections during the preceding 12 months and to provide for the full and timely recovery of the allowed equity return. (2) Other regulatory assets that are not earning a return were not material as of December 31, 2016 and 2015 .

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans [Text Block]	Employee Benefit Plans (a) Pension Plans Substantially all of Houston Electric’s employees participate in CenterPoint Energy’s non-contributory qualified defined benefit plan. Under the cash balance formula, participants accumulate a retirement benefit based upon 5% of eligible earnings and accrued interest. CenterPoint Energy’s funding policy is to review amounts annually in accordance with applicable regulations in order to achieve adequate funding of projected benefit obligations. Pension expense is allocated to Houston Electric based on covered employees. This calculation is intended to allocate pension costs in the same manner as a separate employer plan. Assets of the plan are not segregated or restricted by CenterPoint Energy’s participating subsidiaries. Houston Electric recognized pension expense of $44 million , $35 million and $26 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. In addition to the pension plan, Houston Electric participates in CenterPoint Energy’s non-qualified benefit restoration plans, which allow participants to receive the benefits to which they would have been entitled under the non-contributory pension plan except for federally mandated limits on qualified plan benefits or on the level of compensation on which qualified plan benefits may be calculated. The expense associated with the non-qualified pension plan was $1 million for each of the years ended December 31, 2016 , 2015 and 2014 . (b) Savings Plan Houston Electric participates in CenterPoint Energy’s qualified savings plan, which includes a cash or deferred arrangement under Section 401(k) of the Internal Revenue Code of 1986, as amended (the Code), and an Employee Stock Ownership Plan under Section 4975(e)(7) of the Code. Under the plan, participating employees may contribute a portion of their compensation, on a pre-tax or after-tax basis, generally up to a maximum of 50% of eligible compensation. Houston Electric matches 100% of the first 6% of each employee’s compensation contributed. The matching contributions are fully vested at all times. Participating employees may elect to invest all (prior to January 1, 2016) or a portion of their contributions to the plan in CenterPoint Energy, Inc. common stock, to have dividends reinvested in additional shares or to receive dividend payments in cash on any investment in CenterPoint Energy, Inc. common stock, and to transfer all or part of their investment in CenterPoint Energy, Inc. common stock to other investment options offered by the plan. Effective January 1, 2016 the savings plan was amended to limit the percentage of future contributions that could be invested in CenterPoint Energy, Inc. common stock to 25% and to prohibit transfers of account balances where the transfer would result in more than 25% of a participant’s total account balance invested in CenterPoint Energy, Inc. common stock. The savings plan has significant holdings of CenterPoint Energy, Inc. common stock. As of December 31, 2016 , 14,216,986 shares of CenterPoint Energy, Inc. common stock were held by the savings plan, which represented approximately 17% of its investments. Given the concentration of the investments in CenterPoint Energy, Inc. common stock, the savings plan and its participants have market risk related to this investment. CenterPoint Energy allocates to Houston Electric the savings plan benefit expense related to Houston Electric’s employees. Savings plan benefit expense was $15 million , $14 million and $13 million for each of the years ended December 31, 2016 , 2015 and 2014 . (c) Postretirement Benefits Houston Electric’s employees participate in CenterPoint Energy’s benefit plans which provide certain healthcare and life insurance benefits for retired employees on both a contributory and non-contributory basis. Employees become eligible for these benefits if they have met certain age and service requirements at retirement, as defined in the plans. Such benefit costs are accrued over the active service period of employees. Effective January 1, 2017, members of the IBEW Local Union 66 who retire on or after January 1, 2017, and their dependents, will receive any retiree medical and prescription drug benefits exclusively through the NECA/IBEW Family Medical Care Plan pursuant to the terms of the renegotiated collective bargaining agreement entered into in May 2016. Houston Electric is required to fund a portion of its obligations in accordance with rate orders. The net postretirement benefit cost includes the following components: Year Ended December 31, 2016 2015 2014 (in millions) Service cost - benefits earned during the period $ 1 $ 1 $ 1 Interest cost on accumulated benefit obligation 10 13 14 Expected return on plan assets (5 ) (6 ) (6 ) Amortization of transition obligation — — 4 Amortization of prior service credit (4 ) (2 ) (2 ) Amortization of loss 1 3 1 Curtailment (4 ) — — Net postretirement benefit cost (credit) $ (1 ) $ 9 $ 12 Houston Electric used the following assumptions to determine net postretirement benefit costs: Year Ended December 31, 2016 2015 2014 Discount rate 4.35 % 3.90 % 4.75 % Expected return on plan assets 5.00 % 5.45 % 6.00 % In determining net periodic benefits cost, Houston Electric uses fair value, as of the beginning of the year, as its basis for determining expected return on plan assets. Following are reconciliations of Houston Electric’s beginning and ending balances of its postretirement benefit plan’s benefit obligation, plan assets and funded status for 2016 and 2015 . The measurement dates for plan assets and obligations were December 31, 2016 and 2015 . December 31, 2016 2015 (in millions) Change in Benefit Obligation Accumulated benefit obligation, beginning of year $ 283 $ 347 Service cost 1 1 Interest cost 10 13 Benefits paid (20 ) (17 ) Participant contributions 3 3 Medicare drug reimbursement 1 1 Plan amendment (1) (65 ) (4 ) Actuarial (gain) loss 4 (61 ) Accumulated benefit obligation, end of year $ 217 $ 283 Change in Plan Assets Plan assets, beginning of year $ 110 $ 115 Benefits paid (20 ) (17 ) Employer contributions 10 9 Participant contributions 3 3 Actual investment return 5 — Plan amendment (2) (20 ) — Plan assets, end of year $ 88 $ 110 Amounts Recognized in Balance Sheets Other liabilities-benefit obligations $ (129 ) $ (173 ) Net liability, end of year $ (129 ) $ (173 ) Actuarial Assumptions Discount rate 4.15 % 4.35 % Expected long-term return on assets 4.75 % 5.00 % Healthcare cost trend rate assumed for the next year - Pre 65 5.75 % 6.00 % Healthcare cost trend rate assumed for the next year - Post 65 10.65 % 5.50 % Prescription drug cost trend rate assumed for the next year 10.75 % 11.00 % Rate to which the cost trend rate is assumed to decline (ultimate trend rate) 4.50 % 5.00 % Year that the healthcare rate reaches the ultimate trend rate 2024 2024 Year that the prescription drug rate reaches the ultimate trend rate 2024 2024 (1) The Postretirement plan was amended during 2016 to change retiree medical coverage, effective January 1, 2017, as follows: (i) members of the IBEW Local Union 66 who retire on or after January 1, 2017, and their dependents, will receive any retiree medical and prescription drug coverage exclusively through the NECA/IBEW Family Medical Care Plan pursuant to the terms of the renegotiated collective bargaining agreement entered into in May 2016; and (ii) Medicare eligible post-65 retirees will receive coverage through a Medicare Advantage Program, an insured benefit, in lieu of the previous self-insured benefit. These changes resulted in a reduction in our Postretirement Plan liability of $65 million as of December 31, 2016. (2) In May 2016, Houston Electric entered into a renegotiated collective bargaining agreement with the IBEW Local Union 66 and amended the Houston Electric Union Postretirement Trust. The amendment resulted in a split of the trust into two segregated and restricted accounts, one holds assets for the benefit of current, retired on or before December 31, 2016, union retirees and one holds assets for the benefit of post-2016 union retirees who are now covered exclusively by the NECA/IBEW Family Medical Care Plan. Accordingly, $20 million was transferred to the account for post-2016 union retirees. The discount rate assumption was determined by matching the projected cash flows of CenterPoint Energy’s plans against a hypothetical yield curve of high-quality corporate bonds represented by a series of annualized individual discount rates from one-half to 99 years . The expected rate of return assumption was developed by a weighted-average return analysis of the targeted asset allocation of CenterPoint Energy’s plans and the expected real return for each asset class, based on the long-term capital market assumptions, adjusted for investment fees and diversification effects, in addition to expected inflation. For measurement purposes, medical costs are assumed to increase to 5.75% and 10.65% for the pre-65 and post-65 retirees during 2017 , respectively, and the prescription cost is assumed to increase to 10.75% during 2017 , after which these rates decrease until reaching the ultimate trend rate of 4.50% in 2024. Houston Electric does not have amounts recognized in accumulated other comprehensive income related to its postretirement benefit plans as of December 31, 2016 and 2015 . Unrecognized costs were recorded as a regulatory asset because Houston Electric historically and currently recovers postretirement expenses in rates. Assumed healthcare cost trend rates have a significant effect on the reported amounts for Houston Electric’s postretirement benefit plans. A 1% change in the assumed healthcare cost trend rate would have the following effects: 1% Increase 1% Decrease (in millions) Effect on the postretirement benefit obligation $ 10 $ 10 Effect on total of service and interest cost 1 — In managing the investments associated with the postretirement benefit plans, Houston Electric’s objective is to preserve and enhance the value of plan assets while maintaining an acceptable level of volatility. These objectives are expected to be achieved through an investment strategy that manages liquidity requirements while maintaining a long-term horizon in making investment decisions and efficient and effective management of plan assets. As part of the investment strategy discussed above, Houston Electric has adopted and maintained the following asset allocation ranges for its postretirement benefit plans: U.S. equity 13–23% International equity 3–13% Fixed income 69–79% Cash 0–2% The following tables present by level, within the fair value hierarchy, Houston Electric’s postretirement plan assets as of December 31, 2016 and 2015 , by asset category as follows: Fair Value Measurements as of December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Mutual funds (1) $ 88 $ — $ — $ 88 Total $ 88 $ — $ — $ 88 (1) 73% of the amount invested in mutual funds was in fixed income securities; 19% was in U.S. equities and 8% was in international equities. Fair Value Measurements as of December 31, 2015 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Mutual funds (1) $ 110 $ — $ — $ 110 Total $ 110 $ — $ — $ 110 (1) 73% of the amount invested in mutual funds was in fixed income securities; 19% was in U.S. equities and 8% was in international equities. Houston Electric expects to contribute $9 million to its postretirement benefits plan in 2017 . The following benefit payments are expected to be paid by the postretirement benefit plan: Benefit Payments (in millions) 2017 $ 11 2018 12 2019 13 2020 15 2021 16 2022-2026 90 (d) Postemployment Benefits Houston Electric participates in CenterPoint Energy’s plan which provides postemployment benefits for certain former or inactive employees, their beneficiaries and covered dependents, after employment but before retirement (primarily health care and life insurance benefits for participants in the long-term disability plan). Houston Electric recorded a postemployment expense of $3 million , credit of $1 million and expense of $1 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Amounts relating to postemployment obligations included in Benefit Obligations in the accompanying Consolidated Balance Sheets as of both December 31, 2016 and 2015 were $6 million . (e) Other Non-Qualified Plans Houston Electric participates in CenterPoint Energy’s deferred compensation plans that provide benefits payable to directors, officers and certain key employees or their designated beneficiaries at specified future dates, upon termination, retirement or death. Benefit payments are made from the general assets of Houston Electric. Houston Electric recorded benefit expense relating to these plans of $1 million in each of the years ended December 31, 2016 , 2015 and 2014 . Amounts relating to deferred compensation plans included in Benefit Obligations in the accompanying Consolidated Balance Sheets as of both December 31, 2016 and 2015 were $11 million . (f) Other Employee Matters As of December 31, 2016 , Houston Electric had 2,738 full-time employees, of which approximately 51% were subject to a collective bargaining agreement. The collective bargaining agreement with the IBEW Local 66 expired in May of 2016. Houston Electric successfully negotiated the follow-on agreement in 2016. The new collective bargaining agreement with the IBEW Local 66 expires in May of 2020.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements [Text Block]	Fair Value Measurements Assets and liabilities that are recorded at fair value in the Consolidated Balance Sheets are categorized based upon the level of judgment associated with the inputs used to measure their value. Hierarchical levels, as defined below and directly related to the amount of subjectivity associated with the inputs to fair valuations of these assets and liabilities, are as follows: Level 1: Inputs are unadjusted quoted prices in active markets for identical assets or liabilities at the measurement date. The types of assets carried at Level 1 fair value are investments listed in active markets. As of December 31, 2016 and 2015 , Houston Electric held Level 1 investments of $59 million and $32 million , respectively, which were primarily investments in money market funds and are included in other current assets and other assets in the Consolidated Balance Sheets. Level 2: Inputs, other than quoted prices included in Level 1, are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar instruments in active markets, and inputs other than quoted prices that are observable for the asset or liability. Houston Electric had no Level 2 assets or liabilities as of either December 31, 2016 and 2015 . Level 3: Inputs are unobservable for the asset or liability, and include situations where there is little, if any, market activity for the asset or liability. Unobservable inputs reflect Houston Electric’s judgments about the assumptions market participants would use in determining fair value. Houston Electric had no Level 3 assets or liabilities as of either December 31, 2016 and 2015 . Houston Electric determines the appropriate level for each financial asset and liability on a quarterly basis and recognizes transfers between levels at the end of the reporting period. For the years ended December 31, 2016 and 2015 , there were no transfers between levels. Estimated Fair Value of Financial Instruments The fair values of cash and cash equivalents and short-term borrowings are estimated to be approximately equivalent to carrying amounts and have been excluded from the table below. The fair value of each debt instrument is determined by multiplying the principal amount of each debt instrument by the market price. These assets and liabilities, which are not measured at fair value in the Consolidated Balance Sheets but for which the fair value is disclosed, would be classified as Level 1 in the fair value hierarchy. December 31, 2016 December 31, 2015 Carrying Fair Carrying Amount Fair Value (in millions) Financial liabilities: Long-term debt, including current portion $ 4,865 $ 5,079 $ 4,859 $ 5,086

Related Party Transactions and

Related Party Transactions and Major Customers	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions and Major Customers [Text Block]	Related Party Transactions and Major Customers (a) Related Party Transactions Houston Electric participates in a money pool through which it can borrow or invest on a short-term basis. Funding needs are aggregated and external borrowing or investing is based on the net cash position. The net funding requirements of the money pool are expected to be met with borrowings under CenterPoint Energy’s revolving credit facility or the sale of CenterPoint Energy’s commercial paper. Houston Electric had investments in the money pool of $96 million and borrowings from the money pool of $312 million as of December 31, 2016 and 2015 , respectively, which are included in accounts and notes receivable-affiliated companies and accounts and notes payable-affiliated companies, respectively, in the Consolidated Balance Sheets. As of December 31, 2016 , Houston Electric’s money pool investments had a weighted-average interest rate of 1.04% . For the years ended December 31, 2016 , 2015 and 2014 , Houston Electric had affiliate related net interest expense of $4 million , $1 million and less than $1 million , respectively. CenterPoint Energy provides some corporate services to Houston Electric. The costs of services have been charged directly to Houston Electric using methods that management believes are reasonable. These methods include negotiated usage rates, dedicated asset assignment and proportionate corporate formulas based on operating expenses, assets, gross margin, employees and a composite of assets, gross margin and employees. CERC provides certain services to Houston Electric. These services are billed at actual cost, either directly or as an allocation and include line locating and other miscellaneous services. Additionally, Houston Electric provides a number of services to CERC. These services are billed at actual cost, either directly or as an allocation and include fleet services, shop services, geographic services, surveying and right-of-way services, radio communications, data circuit management and field operations. These charges are not necessarily indicative of what would have been incurred had Houston Electric not been an affiliate. Amounts charged to/from Houston Electric for these services were as follows and are included primarily in operation and maintenance expenses: Year Ended December 31, 2016 2015 2014 (in millions) Corporate service charges $ 179 $ 176 $ 159 Charges from CERC for services provided 7 6 5 Billings to CERC for services provided (15 ) (18 ) (17 ) Houston Electric paid dividends of $135 million , $252 million and $-0- on its common shares to Utility Holding, LLC in 2016 , 2015 and 2014 , respectively. In 2016 and 2014, CenterPoint Energy made an equity contribution of $374 million and $90 million , respectively, to Houston Electric. (b) Major Customers Houston Electric’s transmission and distribution revenues from major customers are as follows: Year Ended December 31, 2016 2015 2014 (in millions) Affiliates of NRG $ 698 $ 741 $ 735 Affiliates of Energy Future Holdings $ 220 $ 220 $ 189

Long-term Debt

Long-term Debt	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Long-term Debt [Text Block]	Long-term Debt December 31, 2016 December 31, 2015 Long-Term Current (1) Long-Term (2) Current (1) (in millions) Long-term debt: Bank Loans $ — $ — $ 200 $ — First mortgage bonds 9.15% due 2021 102 — 102 — General mortgage bonds 1.85% to 6.95% due 2021 to 2044 (3) 2,512 — 1,912 — System restoration bonds 3.46% to 4.243% due 2018 to 2022 312 53 365 50 Transition bonds 0.901% to 5.302% due 2017 to 2024 1,560 358 1,918 341 Unamortized debt issuance costs (23 ) — (21 ) — Unamortized discount and premium, net (9 ) — (8 ) — Total long-term debt $ 4,454 $ 411 $ 4,468 $ 391 (1) Includes amounts due or scheduled to be paid within one year of the date noted. (2) Includes $21 million of unamortized debt issuance costs to reflect adoption of ASU 2015-03. (3) Debt issued as collateral is excluded from the financial statements because of the contingent nature of the obligation. Retirement of Bonds. In December 2016, Houston Electric retired $56 million of collateralized pollution control bonds that had been held for remarketing. These bonds were not reflected on the consolidated financial statements because Houston Electric was both the obligor on the bonds and the current owner of the bonds. Debt Issuances. Houston Electric issued the following general mortgage bonds during 2016 and as of February 10, 2017: Issuance Date Aggregate Principal Amount Interest Rate Maturity Date (in millions) May 2016 $ 300 1.85% 2021 August 2016 300 2.40% 2026 January 2017 300 3.00% 2027 The proceeds from the issuance of these bonds were used to repay short-term debt and for limited liability company purposes. Hedging of Interest Expense for Future Debt Issuances. In April 2016, Houston Electric entered into forward interest rate agreements with several counterparties, having an aggregate notional amount of $150 million . These agreements were executed to hedge, in part, volatility in the 5-year U.S. treasury rate by reducing Houston Electric’s exposure to variability in cash flows related to interest payments of Houston Electric’s $300 million issuance of fixed rate debt in May 2016. These forward interest rate agreements were designated as cash flow hedges. The realized gains and losses associated with the agreements were immaterial. In June and July 2016, Houston Electric entered into forward interest rate agreements with several counterparties, having an aggregate notional amount of $300 million . These agreements were executed to hedge, in part, volatility in the 10-year U.S. treasury rate by reducing Houston Electric’s exposure to variability in cash flows related to interest payments of Houston Electric’s $300 million issuance of fixed rate debt in August 2016. These forward interest rate agreements were designated as cash flow hedges. Accordingly, the effective portion of realized gains associated with the agreements, which totaled $1.1 million , is a component of accumulated other comprehensive income and will be amortized over the life of the bonds. The ineffective portion of the gains and losses was recorded in income and was immaterial. In January 2017, Houston Electric entered into forward interest rate agreements with several counterparties, having an aggregate notional amount of $150 million . These agreements were executed to hedge, in part, volatility in the 10-year U.S. treasury rate by reducing Houston Electric’s exposure to variability in cash flows related to interest payments of Houston Electric’s $300 million issuance of fixed rate debt in January 2017. These forward interest rate agreements were designated as cash flow hedges. Accordingly, the effective portion of unrealized losses associated with the agreements, which totaled approximately $0.5 million , will be a component of accumulated other comprehensive income in 2017 and will be amortized over the life of the bonds. Securitization Bonds. As of December 31, 2016 , Houston Electric had special purpose subsidiaries consisting of the Bond Companies, which it consolidates. The consolidated special purpose subsidiaries are wholly-owned, bankruptcy remote entities that were formed solely for the purpose of purchasing and owning transition or system restoration property through the issuance of transition bonds or system restoration bonds and activities incidental thereto. These Securitization Bonds are payable only through the imposition and collection of “transition” or “system restoration” charges, as defined in the Texas Public Utility Regulatory Act, which are irrevocable, non-bypassable charges to provide recovery of authorized qualified costs. Houston Electric has no payment obligations in respect of the Securitization Bonds other than to remit the applicable transition or system restoration charges it collects. Each special purpose entity is the sole owner of the right to impose, collect and receive the applicable transition or system restoration charges securing the bonds issued by that entity. Creditors of CenterPoint Energy or Houston Electric have no recourse to any assets or revenues of the Bond Companies (including the transition and system restoration charges), and the holders of Securitization Bonds have no recourse to the assets or revenues of CenterPoint Energy or Houston Electric. Revolving Credit Facility. December 31, 2016 December 31, 2015 Size of Loans Letters Size of Loans (1) Letters (in millions) $ 300 $ — $ 4 $ 300 $ 200 $ 4 (1) Weighted average interest rate was 1.64% as of December 31, 2015. Execution Date Size of Facility Draw Rate of LIBOR plus (1) Financial Covenant Limit on Debt to Capital Ratio (3) Debt to Capital Ratio as of December 31, 2016 (2) Termination Date (in millions) March 3, 2016 $ 300 1.125% 65% 47.4% March 3, 2021 (1) Based on current credit ratings. (2) As defined in the revolving credit facility agreement, excluding Securitization Bonds. (3) The financial covenant limit will temporarily increase from 65% to 70% if Houston Electric experiences damage from a natural disaster in its service territory and Houston Electric certifies to the administrative agent that Houston Electric has incurred system restoration costs reasonably likely to exceed $100 million in a consecutive twelve -month period, all or part of which Houston Electric intends to seek to recover through securitization financing. Such temporary increase in the financial covenant would be in effect from the date Houston Electric delivers its certification until the earliest to occur of (i) the completion of the securitization financing, (ii) the first anniversary of Houston Electric’s certification or (iii) the revocation of such certification. Houston Electric was in compliance with all financial debt covenants as of December 31, 2016. Maturities . Maturities of long-term debt, capital leases and sinking fund requirements are as follows: Houston Electric Securitization Bonds (in millions) 2017 $ — $ 411 2018 — 434 2019 — 458 2020 — 231 2021 402 211 Liens. As of December 31, 2016 , Houston Electric’s assets were subject to liens securing approximately $102 million of first mortgage bonds. Sinking or improvement fund and replacement fund requirements on the first mortgage bonds may be satisfied by certification of property additions. Sinking fund and replacement fund requirements for 2016 , 2015 and 2014 have been satisfied by certification of property additions. The replacement fund requirement to be satisfied in 2017 is approximately $240 million , and the sinking fund requirement to be satisfied in 2017 is approximately $1.6 million . Houston Electric expects to meet these 2017 obligations by certification of property additions. As of December 31, 2016 , Houston Electric’s assets were also subject to liens securing approximately $2.6 billion of general mortgage bonds, which are junior to the liens of the first mortgage bonds.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes [Text Block]	Income Taxes The components of Houston Electric’s income tax expense were as follows: Year Ended December 31, 2016 2015 2014 (in millions) Current income tax expense: Federal $ 165 $ 106 $ 136 State 18 21 19 Total current expense 183 127 155 Deferred income tax expense (benefit): Federal (34 ) 18 (24 ) Total deferred expense (benefit) (34 ) 18 (24 ) Total income tax expense $ 149 $ 145 $ 131 A reconciliation of income tax expense using the federal statutory income tax rate to the actual income tax expense and resulting effective income tax rate is as follows: Year Ended December 31, 2016 2015 2014 (in millions) Income before income taxes $ 425 $ 406 $ 383 Federal statutory income tax rate 35 % 35 % 35 % Expected federal income tax expense 149 142 134 Increase (decrease) in tax expense resulting from: State income tax expense, net of federal income tax 12 14 12 Other, net (12 ) (11 ) (15 ) Total — 3 (3 ) Total income tax expense $ 149 $ 145 $ 131 Effective tax rate 35 % 36 % 34 % In 2014, Houston Electric recognized a $6 million reversal of previously accrued taxes as a result of final 2013 income tax returns filed in 2014. The tax effects of temporary differences that give rise to significant portions of deferred tax assets and liabilities were as follows: December 31, 2016 2015 (in millions) Deferred tax assets: Benefits and compensation $ 47 $ 69 Loss and credit carryforwards — 6 AROs 12 13 Other 4 7 Total deferred tax assets 63 95 Deferred tax liabilities: Property, plant, and equipment 1,541 1,447 Regulatory assets/liabilities, net 525 680 Total deferred tax liabilities 2,066 2,127 Net deferred tax liabilities $ 2,003 $ 2,032 Houston Electric is a member of the U.S. federal consolidated income tax return of CenterPoint Energy. Houston Electric reports its income tax provision on a separate entity basis pursuant to a tax sharing agreement with CenterPoint Energy. Uncertain Income Tax Positions. Houston Electric reported no uncertain tax liability as of December 31, 2016, 2015 and 2014. Houston Electric expects no significant change to the uncertain tax liability over the next twelve months ending December 31, 2017. Tax Audits and Settlements. Tax years through 2014 have been audited and settled with the IRS. For the 2015, 2016 and 2017 tax years, CenterPoint Energy is a participant in the IRS’s Compliance Assurance Process.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies [Text Block]	Commitments and Contingencies (a) Lease Commitments Houston Electric currently has obligations under non-cancelable long-term operating leases of less than $1 million per year for the years 2017 to 2021 . Total lease expense for all operating leases was less than $1 million in each of the years ended December 31, 2016 , 2015 and 2014 . (b) Legal, Environmental and Other Matters Legal Matters Gas Market Manipulation Cases . CenterPoint Energy, Houston Electric or their predecessor, Reliant Energy, and certain of their former subsidiaries have been named as defendants in certain lawsuits described below. Under a master separation agreement between CenterPoint Energy and a former subsidiary, RRI, CenterPoint Energy and its subsidiaries are entitled to be indemnified by RRI and its successors for any losses, including certain attorneys’ fees and other costs, arising out of these lawsuits. In May 2009, RRI sold its Texas retail business to a subsidiary of NRG and RRI changed its name to RRI Energy, Inc. In December 2010, Mirant Corporation merged with and became a wholly-owned subsidiary of RRI, and RRI changed its name to GenOn. In December 2012, NRG acquired GenOn through a merger in which GenOn became a wholly-owned subsidiary of NRG. None of the sale of the retail business, the merger with Mirant Corporation, or the acquisition of GenOn by NRG alters RRI’s (now GenOn’s) contractual obligations to indemnify CenterPoint Energy and its subsidiaries, including Houston Electric, for certain liabilities, including their indemnification obligations regarding the gas market manipulation litigation. A large number of lawsuits were filed against numerous gas market participants in a number of federal and western state courts in connection with the operation of the natural gas markets in 2000–2002. CenterPoint Energy and its affiliates have since been released or dismissed from all such cases. CES, a subsidiary of CERC Corp., was a defendant in a case now pending in federal court in Nevada alleging a conspiracy to inflate Wisconsin natural gas prices in 2000–2002. On May 24, 2016, the district court granted CES’s motion for summary judgment, dismissing CES from the case. The plaintiffs have appealed that ruling. CenterPoint Energy and CES intend to continue vigorously defending against the plaintiffs’ claims. Houston Electric does not expect the ultimate outcome of this matter to have a material adverse effect on its financial condition, results of operations or cash flows. Environmental Matters Asbestos. Some facilities owned by Houston Electric contain or have contained asbestos insulation and other asbestos-containing materials. CenterPoint Energy and its subsidiaries, including Houston Electric, are from time to time named, along with numerous others, as defendants in lawsuits filed by a number of individuals who claim injury due to exposure to asbestos, and CenterPoint Energy anticipates that additional claims may be asserted in the future. Although their ultimate outcome cannot be predicted at this time, Houston Electric does not expect these matters, either individually or in the aggregate, to have a material adverse effect on its financial condition, results of operations or cash flows. Other Environmental. From time to time, Houston Electric identifies the presence of environmental contaminants during its operations or on property where its predecessor companies have conducted operations. Other such sites involving contaminants may be identified in the future. Houston Electric has and expects to continue to remediate identified sites consistent with its legal obligations. From time to time, Houston Electric has received notices from regulatory authorities or others regarding its status as a potentially responsible party in connection with sites found to require remediation due to the presence of environmental contaminants. In addition, Houston Electric has been named from time to time as a defendant in litigation related to such sites. Although the ultimate outcome of such matters cannot be predicted at this time, Houston Electric does not expect these matters, either individually or in the aggregate, to have a material adverse effect on its financial condition, results of operations or cash flows. Other Proceedings Houston Electric is involved in other legal, environmental, tax and regulatory proceedings before various courts, regulatory commissions and governmental agencies regarding matters arising in the ordinary course of business. From time to time, Houston Electric is also a defendant in legal proceedings with respect to claims brought by various plaintiffs against broad groups of participants in the energy industry. Some of these proceedings involve substantial amounts. Houston Electric regularly analyzes current information and, as necessary, provides accruals for probable and reasonably estimable liabilities on the eventual disposition of these matters. Houston Electric does not expect the disposition of these matters to have a material adverse effect on Houston Electric’s financial condition, results of operations or cash flows.

Unaudited Quarterly Information

Unaudited Quarterly Information	12 Months Ended
	Dec. 31, 2016
Unaudited Quarterly Information [Abstract]
Unaudited Quarterly Information [Text Block]	Unaudited Quarterly Information Summarized quarterly financial data is as follows: Year Ended December 31, 2016 First Quarter Second Quarter Third Quarter Fourth Quarter (in millions) Revenues $ 656 $ 763 $ 909 $ 731 Operating income 79 158 258 132 Net income 17 71 136 52 Year Ended December 31, 2015 First Quarter Second Quarter Third Quarter Fourth Quarter (in millions) Revenues $ 617 $ 705 $ 827 $ 697 Operating income 101 158 244 105 Net income 31 69 124 37

Summary of Significant Accoun20

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Principles of Consolidation	Principles of Consolidation The accounts of Houston Electric and its wholly-owned subsidiaries are included in Houston Electric’s consolidated financial statements. All intercompany transactions and balances are eliminated in consolidation. As of December 31, 2016 , Houston Electric had VIEs consisting of the Bond Companies, which it consolidates. The consolidated VIEs are wholly-owned, bankruptcy remote special purpose entities that were formed specifically for the purpose of securitizing transition and system restoration related property. Creditors of Houston Electric have no recourse to any assets or revenues of the Bond Companies. The bonds issued by these VIEs are payable only from and secured by transition and system restoration property and the bondholders have no recourse to the general credit of Houston Electric.
Revenues	Revenues Houston Electric records revenue for electricity delivery under the accrual method and these revenues are recognized upon delivery to customers. Electricity deliveries not billed by month-end are accrued based on actual AMS data, daily supply volumes and applicable rates.
Long-lived Assets and Intangibles	Long-lived Assets and Intangibles Houston Electric records property, plant and equipment at historical cost. Houston Electric expenses repair and maintenance costs as incurred. Houston Electric periodically evaluates long-lived assets, including property, plant and equipment, and specifically identifiable intangibles, when events or changes in circumstances indicate that the carrying value of these assets may not be recoverable. The determination of whether an impairment has occurred is based on an estimate of undiscounted cash flows attributable to the assets compared to the carrying value of the assets.
Regulatory Assets and Liabilities	Regulatory Assets and Liabilities Houston Electric applies the guidance for accounting for regulated operations. Houston Electric’s rate-regulated subsidiaries may collect revenues subject to refund pending final determination in rate proceedings. In connection with such revenues, estimated rate refund liabilities are recorded which reflect management’s current judgment of the ultimate outcomes of the proceedings. Houston Electric had current regulatory liabilities of $7 million and $2 million as of December 31, 2016 and 2015, respectively, included in other current liabilities in its Consolidated Balance Sheets. Houston Electric recognizes removal costs as a component of depreciation expense in accordance with regulatory treatment. As of December 31, 2016 and 2015 , these removal costs of $345 million and $350 million , respectively, are classified as regulatory liabilities in Houston Electric’s Consolidated Balance Sheets. In addition, a portion of the amount of removal costs that relate to AROs has been reclassified from a regulatory liability to an asset retirement liability in accordance with accounting guidance for AROs.
Depreciation and Amortization Expense	Depreciation and Amortization Expense Depreciation is computed using the straight-line method based on economic lives or a regulatory-mandated recovery period. Transition and system restoration property is being amortized over the expected life of the Securitization Bonds ( 12 to 14 years ), based on estimated revenue from transition or system restoration charges, interest accruals and other expenses. Other amortization expense includes amortization of regulatory assets and other intangibles.
Capitalization of Interest and AFUDC	Capitalization of Interest and AFUDC Interest and AFUDC are capitalized as a component of projects under construction and are amortized over the assets’ estimated useful lives once the assets are placed in service. AFUDC represents the composite interest cost of borrowed funds and a reasonable return on the equity funds used for construction. Although AFUDC increases both utility plant and earnings, it is realized in cash when the assets are included in rates. During 2016 , 2015 and 2014 , Houston Electric capitalized interest and AFUDC of $6 million , $8 million and $10 million , respectively. During 2016 , 2015 and 2014 , Houston Electric recorded AFUDC equity of $6 million , $12 million and $14 million , respectively, which is included in Other Income in its Statements of Consolidated Income.
Income Taxes	Income Taxes Houston Electric is a member of the U.S. federal consolidated income tax return of CenterPoint Energy. Houston Electric reports its income tax provision on a separate entity basis pursuant to a tax sharing agreement with CenterPoint Energy. Houston Electric uses the asset and liability method of accounting for deferred income taxes. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. A valuation allowance is established against deferred tax assets for which management believes realization is not considered to be more likely than not. Houston Electric recognizes interest and penalties as a component of income tax expense. Current federal and certain state income taxes are payable to or receivable from CenterPoint Energy.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts Accounts receivable are recorded at the invoiced amount and do not bear interest. It is the policy of management to review the outstanding accounts receivable monthly, as well as the bad debt write-offs experienced in the past, and establish an allowance for doubtful accounts. Account balances are charged off against the allowance when management determines it is probable the receivable will not be recovered. The provision for doubtful accounts in Houston Electric’s Statements of Consolidated Income for 2016 , 2015 and 2014 was less than $1 million , less than $1 million and $3 million , respectively.
Inventory	Inventory Inventory consists principally of materials and supplies and is valued at the lower of average cost or market. Materials and supplies are recorded to inventory when purchased and subsequently charged to expense or capitalized to plant when installed.
Statements of Consolidated Cash Flows	Statements of Consolidated Cash Flows For purposes of reporting cash flows, Houston Electric considers cash equivalents to be short-term, highly-liquid investments with maturities of three months or less from the date of purchase. In connection with the issuance of securitization bonds, Houston Electric was required to establish restricted cash accounts to collateralize the bonds that were issued in these financing transactions. These restricted cash accounts are not available for withdrawal until the maturity of the bonds and are not included in cash and cash equivalents. These restricted cash accounts of $40 million and $35 million as of December 31, 2016 and 2015 , respectively, are included in other current assets in Houston Electric’s Consolidated Balance Sheets. For additional information regarding Securitization Bonds, see Note 8 . Cash and cash equivalents included $340 million and $264 million as of December 31, 2016 and 2015 , respectively, that was held by the Bond Companies solely to support servicing the Securitization Bonds.
New Accounting Pronouncements	New Accounting Pronouncements In February 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis (ASU 2015-02). ASU 2015 -02 changes the analysis that reporting organizations must perform to evaluate whether they should consolidate certain legal entities, such as limited partnerships. The changes include, among others, modification of the evaluation of whether limited partnerships and similar legal entities are VIEs or voting interest entities and elimination of the presumption that a general partner should consolidate a limited partnership. ASU 2015-02 does not amend the related party guidance for situations in which power is shared between two or more entities that hold interests in a VIE. Houston Electric adopted ASU 2015-02 on January 1, 2016, which did not have a material impact on its financial position, results of operations, cash flows and disclosures. In April 2015, the FASB issued ASU No. 2015-03, Interest-Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Cost (ASU 2015-03) . ASU 2015-03 requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by ASU 2015-03. Houston Electric adopted ASU 2015-03 retrospectively on January 1, 2016, which resulted in a reduction of both other long-term assets and total long-term debt on its Consolidated Balance Sheets. Houston Electric had debt issuance costs, excluding amounts related to credit facility arrangements, of $23 million and $21 million as a reduction to long-term debt on its Consolidated Balance Sheets as of December 31, 2016 and 2015 , respectively. In May 2015, the FASB issued ASU No. 2015-07, Fair Value Measurement (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent) (ASU 2015-07). ASU 2015-07 removes the requirement to categorize within the fair value hierarchy investments for which fair values are measured at NAV using the practical expedient. Entities will be required to disclose the fair value of investments measured using the NAV practical expedient so that financial statement users can reconcile amounts reported in the fair value hierarchy table to amounts reported on the balance sheet. Houston Electric retrospectively adopted ASU 2015-07 on January 1, 2016, which impacts its employee benefit plan disclosures. See Note 5 for the impacts on the employee benefit plan disclosures. This standard did not have an impact on Houston Electric’s financial position, results of operations or cash flows. In September 2015, the FASB issued ASU No. 2015-16, Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments (ASU 2015-16). ASU 2015-16 eliminates the requirement for an acquirer in a business combination to account for measurement-period adjustments retrospectively. Instead, an acquirer would recognize a measurement-period adjustment during the period in which the amount of the adjustment is determined. Houston Electric prospectively adopted ASU 2015-16 on January 1, 2016, which did not have an impact on its financial position, results of operations or cash flows. In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-01). ASU 2016-01 requires equity investments that do not result in consolidation and are not accounted for under the equity method to be measured at fair value and to recognize any changes in fair value in net income unless the investments qualify for the new practicability exception. It does not change the guidance for classifying and measuring investments in debt securities and loans. ASU 2016-01 also changes certain disclosure requirements and other aspects related to recognition and measurement of financial assets and financial liabilities. ASU 2016-01 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017. As of the first reporting period in which the guidance is adopted, a cumulative-effect adjustment to beginning retained earnings will be made, with two features that will be adopted prospectively. Houston Electric is currently assessing the impact that this standard will have on its financial position, results of operations, cash flows and disclosures. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (ASU 2016-02). ASU 2016-02 provides a comprehensive new lease model that requires lessees to recognize assets and liabilities for most leases and would change certain aspects of lessor accounting. ASU 2016-02 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. A modified retrospective adoption approach is required. Houston Electric is currently assessing the impact that this standard will have on its financial position, results of operations, cash flows and disclosures. In 2016, the FASB issued ASUs which amended ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) . ASU 2014-09, as amended, provides a comprehensive new revenue recognition model that requires revenue to be recognized in a manner that depicts the transfer of goods or services to a customer at an amount that reflects the consideration expected to be received in exchange for those goods or services. Early adoption is not permitted, and entities have the option of using either a full retrospective or a modified retrospective adoption approach. Houston Electric is currently evaluating its revenue streams under these ASUs and has not yet identified any significant changes as the result of these new standards. A substantial amount of Houston Electric’s revenues are tariff based, which we do not anticipate significant impact from these ASUs. Houston Electric is considering the impacts of the new guidance on its ability to recognize revenue for certain contracts when collectability is uncertain and its accounting for contributions in aid of construction. Houston Electric expects to adopt these ASUs on January 1, 2018 and is evaluating the method of adoption. In August 2016, the FASB issued ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (ASU 2016-15). ASU 2016-15 provides clarifying guidance on the classification of certain cash receipts and payments in the statement of cash flows and eliminates the variation in practice related to such classifications. ASU 2016-15 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. A retrospective adoption approach is required. Houston Electric is currently assessing the impact that this standard will have on its statement of cash flows. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash (ASU 2016-18). ASU 2016-18 requires a statement of cash flows explain the change during the period in the total of cash, cash equivalents, restricted cash and restricted cash equivalents. As a result the statement of cash flows will no longer present transfers between cash and cash equivalents and restricted cash and restricted cash equivalents. When cash, cash equivalents, restricted cash and restricted cash equivalents are presented in more than one line item on the balance sheet, the new guidance requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheet. ASU 2016-18 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted. A retrospective adoption approach is required. Houston Electric is currently assessing the impact that this standard will have on its statement of cash flows and disclosures. In January 2017, the FASB issued ASU No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business (ASU 2017-01). ASU 2017-01 revises the definition of a business. If substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets, then under ASU 2017-01, the asset or group of assets is not a business. The guidance also requires a business to include at least one substantive process and narrows the definition of outputs to be more closely aligned with how outputs are described in ASC 606. ASU 2017-01 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted in certain circumstances. A prospective adoption approach is required. ASU 2017-01 could have a potential impact on Houston Electric’s accounting for future acquisitions. Management believes that other recently issued standards, which are not yet effective, will not have a material impact on Houston Electric’s consolidated financial position, results of operations or cash flows upon adoption.
Other Current Liabilities	Other Current Liabilities Included in other current liabilities on the Consolidated Balance Sheets as of December 31, 2016 and 2015 was $17 million and $12 million , respectively, of customer deposits primarily held by the Bond Companies.
Environmental Costs	Environmental Costs Houston Electric expenses or capitalizes environmental expenditures, as appropriate, depending on their future economic benefit. Houston Electric expenses amounts that relate to an existing condition caused by past operations that do not have future economic benefit. Houston Electric records undiscounted liabilities related to these future costs when environmental assessments and/or remediation activities are probable and the costs can be reasonably estimated.

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Schedule of Property, Plant and Equipment [Table Text Block]	Property, plant and equipment includes the following: Weighted Average Useful December 31, Lives (in years) 2016 2015 (in millions) Transmission 44 $ 2,402 $ 2,196 Distribution 31 6,965 6,556 Other 14 1,473 1,390 Total 10,840 10,142 Accumulated depreciation 3,443 3,209 Property, plant and equipment, net $ 7,397 $ 6,933
Depreciation and Amortization [Table Text Block]	The following table presents depreciation and amortization expense for 2016 , 2015 and 2014 : Year Ended December 31, 2016 2015 2014 (in millions) Depreciation expense $ 349 $ 316 $ 295 Amortization of securitized regulatory assets 455 365 441 Other amortization 34 24 32 Total depreciation and amortization $ 838 $ 705 $ 768
Asset Retirement Obligation [Table Text Block]	A reconciliation of the changes in the ARO liability is as follows: December 31, 2016 2015 (in millions) Beginning balance $ 37 $ 36 Accretion expense 1 1 Revisions in estimates of cash flows (5 ) — Ending balance $ 33 $ 37

Regulatory Matters (Tables)

Regulatory Matters (Tables)	12 Months Ended
	Dec. 31, 2016
Regulatory Assets and Liabilities, Other Disclosures [Abstract]
Schedule of Regulatory Assets and Liabilities [Table Text Block]	The following is a list of regulatory assets/liabilities reflected on Houston Electric’s Consolidated Balance Sheets as of December 31, 2016 and 2015 : December 31, 2016 2015 (in millions) Securitized regulatory assets $ 1,919 $ 2,373 Unrecognized equity return (1) (329 ) (393 ) Unamortized loss on reacquired debt 84 93 Pension and postretirement-related regulatory asset 34 50 Other long-term regulatory assets (2) 85 88 Total regulatory assets 1,793 2,211 Estimated removal costs 345 350 Other long-term regulatory liabilities 185 192 Total regulatory liabilities 530 542 Total regulatory assets and liabilities, net $ 1,263 $ 1,669 (1) The unrecognized allowed equity return will be recognized as it is recovered in rates through 2024. During the years ended December 31, 2016 , 2015 and 2014 , Houston Electric recognized approximately $64 million , $49 million and $68 million , respectively, of the allowed equity return. The timing of Houston Electric’s recognition of the allowed equity return will vary each period based on amounts actually collected during the period. The actual amounts recovered for the allowed equity return are reviewed and adjusted at least annually by the PUCT to correct any over-collections or under-collections during the preceding 12 months and to provide for the full and timely recovery of the allowed equity return. (2) Other regulatory assets that are not earning a return were not material as of December 31, 2016 and 2015 .

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Schedule of Defined Benefit Plans Disclosures [Table Text Block]	Houston Electric expects to contribute $9 million to its postretirement benefits plan in 2017 . The following benefit payments are expected to be paid by the postretirement benefit plan: Benefit Payments (in millions) 2017 $ 11 2018 12 2019 13 2020 15 2021 16 2022-2026 90 As part of the investment strategy discussed above, Houston Electric has adopted and maintained the following asset allocation ranges for its postretirement benefit plans: U.S. equity 13–23% International equity 3–13% Fixed income 69–79% Cash 0–2% Houston Electric is required to fund a portion of its obligations in accordance with rate orders. The net postretirement benefit cost includes the following components: Year Ended December 31, 2016 2015 2014 (in millions) Service cost - benefits earned during the period $ 1 $ 1 $ 1 Interest cost on accumulated benefit obligation 10 13 14 Expected return on plan assets (5 ) (6 ) (6 ) Amortization of transition obligation — — 4 Amortization of prior service credit (4 ) (2 ) (2 ) Amortization of loss 1 3 1 Curtailment (4 ) — — Net postretirement benefit cost (credit) $ (1 ) $ 9 $ 12 Houston Electric used the following assumptions to determine net postretirement benefit costs: Year Ended December 31, 2016 2015 2014 Discount rate 4.35 % 3.90 % 4.75 % Expected return on plan assets 5.00 % 5.45 % 6.00 % Following are reconciliations of Houston Electric’s beginning and ending balances of its postretirement benefit plan’s benefit obligation, plan assets and funded status for 2016 and 2015 . The measurement dates for plan assets and obligations were December 31, 2016 and 2015 . December 31, 2016 2015 (in millions) Change in Benefit Obligation Accumulated benefit obligation, beginning of year $ 283 $ 347 Service cost 1 1 Interest cost 10 13 Benefits paid (20 ) (17 ) Participant contributions 3 3 Medicare drug reimbursement 1 1 Plan amendment (1) (65 ) (4 ) Actuarial (gain) loss 4 (61 ) Accumulated benefit obligation, end of year $ 217 $ 283 Change in Plan Assets Plan assets, beginning of year $ 110 $ 115 Benefits paid (20 ) (17 ) Employer contributions 10 9 Participant contributions 3 3 Actual investment return 5 — Plan amendment (2) (20 ) — Plan assets, end of year $ 88 $ 110 Amounts Recognized in Balance Sheets Other liabilities-benefit obligations $ (129 ) $ (173 ) Net liability, end of year $ (129 ) $ (173 ) Actuarial Assumptions Discount rate 4.15 % 4.35 % Expected long-term return on assets 4.75 % 5.00 % Healthcare cost trend rate assumed for the next year - Pre 65 5.75 % 6.00 % Healthcare cost trend rate assumed for the next year - Post 65 10.65 % 5.50 % Prescription drug cost trend rate assumed for the next year 10.75 % 11.00 % Rate to which the cost trend rate is assumed to decline (ultimate trend rate) 4.50 % 5.00 % Year that the healthcare rate reaches the ultimate trend rate 2024 2024 Year that the prescription drug rate reaches the ultimate trend rate 2024 2024 (1) The Postretirement plan was amended during 2016 to change retiree medical coverage, effective January 1, 2017, as follows: (i) members of the IBEW Local Union 66 who retire on or after January 1, 2017, and their dependents, will receive any retiree medical and prescription drug coverage exclusively through the NECA/IBEW Family Medical Care Plan pursuant to the terms of the renegotiated collective bargaining agreement entered into in May 2016; and (ii) Medicare eligible post-65 retirees will receive coverage through a Medicare Advantage Program, an insured benefit, in lieu of the previous self-insured benefit. These changes resulted in a reduction in our Postretirement Plan liability of $65 million as of December 31, 2016. (2) In May 2016, Houston Electric entered into a renegotiated collective bargaining agreement with the IBEW Local Union 66 and amended the Houston Electric Union Postretirement Trust. The amendment resulted in a split of the trust into two segregated and restricted accounts, one holds assets for the benefit of current, retired on or before December 31, 2016, union retirees and one holds assets for the benefit of post-2016 union retirees who are now covered exclusively by the NECA/IBEW Family Medical Care Plan. Accordingly, $20 million was transferred to the account for post-2016 union retirees.
Schedule of a one-percent point change In Assumed Health Care Cost Trend Rates [Table Text Block]	Assumed healthcare cost trend rates have a significant effect on the reported amounts for Houston Electric’s postretirement benefit plans. A 1% change in the assumed healthcare cost trend rate would have the following effects: 1% Increase 1% Decrease (in millions) Effect on the postretirement benefit obligation $ 10 $ 10 Effect on total of service and interest cost 1 —
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Text Block]	The following tables present by level, within the fair value hierarchy, Houston Electric’s postretirement plan assets as of December 31, 2016 and 2015 , by asset category as follows: Fair Value Measurements as of December 31, 2016 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Mutual funds (1) $ 88 $ — $ — $ 88 Total $ 88 $ — $ — $ 88 (1) 73% of the amount invested in mutual funds was in fixed income securities; 19% was in U.S. equities and 8% was in international equities. Fair Value Measurements as of December 31, 2015 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Mutual funds (1) $ 110 $ — $ — $ 110 Total $ 110 $ — $ — $ 110 (1) 73% of the amount invested in mutual funds was in fixed income securities; 19% was in U.S. equities and 8% was in international equities.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Estimated Fair Value of Financial Instruments, Debt Instruments [Table Text Block]	The fair values of cash and cash equivalents and short-term borrowings are estimated to be approximately equivalent to carrying amounts and have been excluded from the table below. The fair value of each debt instrument is determined by multiplying the principal amount of each debt instrument by the market price. These assets and liabilities, which are not measured at fair value in the Consolidated Balance Sheets but for which the fair value is disclosed, would be classified as Level 1 in the fair value hierarchy. December 31, 2016 December 31, 2015 Carrying Fair Carrying Amount Fair Value (in millions) Financial liabilities: Long-term debt, including current portion $ 4,865 $ 5,079 $ 4,859 $ 5,086

Related Party Transactions an25

Related Party Transactions and Major Customers Related Party Transactions and Major Customers (Tables)	12 Months Ended
	Dec. 31, 2016
Related Party Transactions [Abstract]
Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]	Houston Electric’s transmission and distribution revenues from major customers are as follows: Year Ended December 31, 2016 2015 2014 (in millions) Affiliates of NRG $ 698 $ 741 $ 735 Affiliates of Energy Future Holdings $ 220 $ 220 $ 189
Schedule of Related Party Transactions [Table Text Block]	CenterPoint Energy provides some corporate services to Houston Electric. The costs of services have been charged directly to Houston Electric using methods that management believes are reasonable. These methods include negotiated usage rates, dedicated asset assignment and proportionate corporate formulas based on operating expenses, assets, gross margin, employees and a composite of assets, gross margin and employees. CERC provides certain services to Houston Electric. These services are billed at actual cost, either directly or as an allocation and include line locating and other miscellaneous services. Additionally, Houston Electric provides a number of services to CERC. These services are billed at actual cost, either directly or as an allocation and include fleet services, shop services, geographic services, surveying and right-of-way services, radio communications, data circuit management and field operations. These charges are not necessarily indicative of what would have been incurred had Houston Electric not been an affiliate. Amounts charged to/from Houston Electric for these services were as follows and are included primarily in operation and maintenance expenses: Year Ended December 31, 2016 2015 2014 (in millions) Corporate service charges $ 179 $ 176 $ 159 Charges from CERC for services provided 7 6 5 Billings to CERC for services provided (15 ) (18 ) (17 )

Long-term Debt (Tables)

Long-term Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Maturities of Long-term Debt [Table Text Block]	Maturities of long-term debt, capital leases and sinking fund requirements are as follows: Houston Electric Securitization Bonds (in millions) 2017 $ — $ 411 2018 — 434 2019 — 458 2020 — 231 2021 402 211
Schedule of Debt [Table Text Block]	December 31, 2016 December 31, 2015 Long-Term Current (1) Long-Term (2) Current (1) (in millions) Long-term debt: Bank Loans $ — $ — $ 200 $ — First mortgage bonds 9.15% due 2021 102 — 102 — General mortgage bonds 1.85% to 6.95% due 2021 to 2044 (3) 2,512 — 1,912 — System restoration bonds 3.46% to 4.243% due 2018 to 2022 312 53 365 50 Transition bonds 0.901% to 5.302% due 2017 to 2024 1,560 358 1,918 341 Unamortized debt issuance costs (23 ) — (21 ) — Unamortized discount and premium, net (9 ) — (8 ) — Total long-term debt $ 4,454 $ 411 $ 4,468 $ 391 (1) Includes amounts due or scheduled to be paid within one year of the date noted. (2) Includes $21 million of unamortized debt issuance costs to reflect adoption of ASU 2015-03. (3) Debt issued as collateral is excluded from the financial statements because of the contingent nature of the obligation. Retirement of Bonds. In December 2016, Houston Electric retired $56 million of collateralized pollution control bonds that had been held for remarketing. These bonds were not reflected on the consolidated financial statements because Houston Electric was both the obligor on the bonds and the current owner of the bonds. Debt Issuances. Houston Electric issued the following general mortgage bonds during 2016 and as of February 10, 2017: Issuance Date Aggregate Principal Amount Interest Rate Maturity Date (in millions) May 2016 $ 300 1.85% 2021 August 2016 300 2.40% 2026 January 2017 300 3.00% 2027
Schedule of Line of Credit Facilities [Table Text Block]	Revolving Credit Facility. December 31, 2016 December 31, 2015 Size of Loans Letters Size of Loans (1) Letters (in millions) $ 300 $ — $ 4 $ 300 $ 200 $ 4 (1) Weighted average interest rate was 1.64% as of December 31, 2015. Execution Date Size of Facility Draw Rate of LIBOR plus (1) Financial Covenant Limit on Debt to Capital Ratio (3) Debt to Capital Ratio as of December 31, 2016 (2) Termination Date (in millions) March 3, 2016 $ 300 1.125% 65% 47.4% March 3, 2021 (1) Based on current credit ratings. (2) As defined in the revolving credit facility agreement, excluding Securitization Bonds. (3) The financial covenant limit will temporarily increase from 65% to 70% if Houston Electric experiences damage from a natural disaster in its service territory and Houston Electric certifies to the administrative agent that Houston Electric has incurred system restoration costs reasonably likely to exceed $100 million in a consecutive twelve -month period, all or part of which Houston Electric intends to seek to recover through securitization financing. Such temporary increase in the financial covenant would be in effect from the date Houston Electric delivers its certification until the earliest to occur of (i) the completion of the securitization financing, (ii) the first anniversary of Houston Electric’s certification or (iii) the revocation of such certification.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Tax Expense [Table Text Block]	The components of Houston Electric’s income tax expense were as follows: Year Ended December 31, 2016 2015 2014 (in millions) Current income tax expense: Federal $ 165 $ 106 $ 136 State 18 21 19 Total current expense 183 127 155 Deferred income tax expense (benefit): Federal (34 ) 18 (24 ) Total deferred expense (benefit) (34 ) 18 (24 ) Total income tax expense $ 149 $ 145 $ 131
Reconciliation Of Expected Federal Income Tax Expense To Actual [Table Text Block]	A reconciliation of income tax expense using the federal statutory income tax rate to the actual income tax expense and resulting effective income tax rate is as follows: Year Ended December 31, 2016 2015 2014 (in millions) Income before income taxes $ 425 $ 406 $ 383 Federal statutory income tax rate 35 % 35 % 35 % Expected federal income tax expense 149 142 134 Increase (decrease) in tax expense resulting from: State income tax expense, net of federal income tax 12 14 12 Other, net (12 ) (11 ) (15 ) Total — 3 (3 ) Total income tax expense $ 149 $ 145 $ 131 Effective tax rate 35 % 36 % 34 %
Income Tax Asset Liability Disclosure [Table Text Block]	The tax effects of temporary differences that give rise to significant portions of deferred tax assets and liabilities were as follows: December 31, 2016 2015 (in millions) Deferred tax assets: Benefits and compensation $ 47 $ 69 Loss and credit carryforwards — 6 AROs 12 13 Other 4 7 Total deferred tax assets 63 95 Deferred tax liabilities: Property, plant, and equipment 1,541 1,447 Regulatory assets/liabilities, net 525 680 Total deferred tax liabilities 2,066 2,127 Net deferred tax liabilities $ 2,003 $ 2,032

Unaudited Quarterly Informati28

Unaudited Quarterly Information Unaudited Quarterly Information (Tables)	12 Months Ended
	Dec. 31, 2016
Unaudited Quarterly Information [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	Summarized quarterly financial data is as follows: Year Ended December 31, 2016 First Quarter Second Quarter Third Quarter Fourth Quarter (in millions) Revenues $ 656 $ 763 $ 909 $ 731 Operating income 79 158 258 132 Net income 17 71 136 52 Year Ended December 31, 2015 First Quarter Second Quarter Third Quarter Fourth Quarter (in millions) Revenues $ 617 $ 705 $ 827 $ 697 Operating income 101 158 244 105 Net income 31 69 124 37

Background (Details)

Background (Details) number in Millions	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of Metered Customers	2.4

Summary of Significant Accoun30

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Significant Accounting Policies [Line Items]
Regulatory liabilities, noncurrent	$ 530	$ 542
Amortization Period, Transition Property (in years)	12 to 14 years
Capitalized Interest Costs, Including Allowance for Funds Used During Construction	$ 6	8	$ 10
Provision for doubtful accounts	1	1	3
Cash and cash equivalents	341	264	290	$ 207
Unamortized debt issuance expense	23	21
Removal Costs [Member]
Significant Accounting Policies [Line Items]
Regulatory liabilities, noncurrent	345	350
Other Income [Member]
Significant Accounting Policies [Line Items]
AFUDC equity	6	12	$ 14
Other Current Liabilities [Member]
Significant Accounting Policies [Line Items]
Regulatory liabilities, current	7	2
Customer deposits	17	12
Prepaid Expenses and Other Current Assets [Member]
Significant Accounting Policies [Line Items]
Restricted cash accounts	40	35
Variable Interest Entity, Primary Beneficiary [Member]
Significant Accounting Policies [Line Items]
Cash and cash equivalents	$ 340	$ 264

Property, Plant and Equipment31

Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment, Net, by Type [Abstract]
Total	$ 10,840	$ 10,142
Accumulated depreciation	3,443	3,209
Property, plant and equipment, net	7,397	6,933
Depreciation, Depletion and Amortization [Abstract]
Depreciation expense	349	316	$ 295
Amortization of securitized regulatory assets	455	365	441
Other amortization	34	24	32
Total depreciation and amortization	838	705	768
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	37	36
Accretion expense	1	1
Revisions in estimates of cash flows	(5)	0
Ending balance	33	37	$ 36
Transmission [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Total	2,402	2,196
Distribution [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Total	6,965	6,556
Other [Member]
Property, Plant and Equipment, Net, by Type [Abstract]
Total	$ 1,473	$ 1,390
Weighted Average [Member] | Transmission [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	44 years
Weighted Average [Member] | Distribution [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	31 years
Weighted Average [Member] | Other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	14 years

Regulatory Matters Regulatory A

Regulatory Matters Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Regulatory Assets And Liabilities [Line Items]
Securitized regulatory assets		$ 1,919	$ 2,373
Unrecognized equity return (1)	[1]	(329)	(393)
Unamortized loss on reacquired debt		84	93
Regulatory assets		1,793	2,211
Regulatory liabilities		530	542
Total regulatory assets and liabilities, net		1,263	1,669
Amount of allowed equity return on the true-up balance that was recognized in the period		64	49	$ 68
Pension and Other Postretirement Plans Costs [Member]
Schedule Of Regulatory Assets And Liabilities [Line Items]
Regulatory assets		34	50
Other Regulatory Assets (Liabilities) [Member]
Schedule Of Regulatory Assets And Liabilities [Line Items]
Regulatory assets	[2]	85	88
Removal Costs [Member]
Schedule Of Regulatory Assets And Liabilities [Line Items]
Regulatory liabilities		345	350
Other Regulatory Assets (Liabilities) [Member]
Schedule Of Regulatory Assets And Liabilities [Line Items]
Regulatory liabilities		$ 185	$ 192
[1]	The unrecognized allowed equity return will be recognized as it is recovered in rates through 2024. During the years ended December 31, 2016, 2015 and 2014, Houston Electric recognized approximately $64 million, $49 million and $68 million, respectively, of the allowed equity return. The timing of Houston Electric’s recognition of the allowed equity return will vary each period based on amounts actually collected during the period. The actual amounts recovered for the allowed equity return are reviewed and adjusted at least annually by the PUCT to correct any over-collections or under-collections during the preceding 12 months and to provide for the full and timely recovery of the allowed equity return.
[2]	Other regulatory assets that are not earning a return were not material as of December 31, 2016 and 2015.

Employee Benefit Plans Pension

Employee Benefit Plans Pension and Postretirement Benefits (Details) - USD ($) $ in Millions		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Percentage of eligible earnings used to determine retirement benefits		5.00%		5.00%
Recognized pension expense				$ 44	$ 35	$ 26
Non Qualified Pension Plan Expense				$ 1	1	1
Maximum Percentage Of Employee Compensation Eligible For Contribution To Savings Plan				50.00%
Description Of Company Match Under Savings Plan				100.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay				6.00%
Defined Contribution Plan, Cost Recognized				$ 15	14	$ 13
Components of net periodic costs [Abstract]
Service cost				1	1
Interest cost				$ 10	$ 13
Assumptions used to determine net periodic benefit (income) cost [Abstract]
Discount rate				4.35%	3.90%	4.75%
Expected long-term return on assets		4.75%	5.00%	5.00%	5.45%	6.00%
Change in Benefit Obligation
Accumulated benefit obligation, beginning of year				$ 283	$ 347
Service cost				1	1
Interest cost				10	13
Benefits paid				(20)	(17)
Participant contributions				3	3
Medicare drug reimbursement				1	1
Plan amendment (1)	[1]			(65)	(4)
Actuarial (gain) loss				4	(61)
Accumulated benefit obligation, end of year		$ 217	$ 283	217	283	$ 347
Change in Plan Assets
Plan assets, beginning of year				110	115
Benefits paid				(20)	(17)
Employer contributions				10	9
Participant contributions				3	3
Actual investment return				5	0
Plan amendment (2)	[2]			(20)	0
Plan assets, end of year		88	110	88	110	$ 115
Amounts Recognized in Balance Sheets
Other liabilities-benefit obligations		$ (148)	$ (192)	$ (148)	$ (192)
Actuarial Assumptions
Discount rate		4.15%	4.35%	4.15%	4.35%
Expected long-term return on assets		4.75%	5.00%	5.00%	5.45%	6.00%
Prescription drug cost trend rate assumed for the next year				10.75%	11.00%
Rate to which the cost trend rate is assumed to decline (ultimate trend rate)				4.50%	5.00%
Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract]
Effect of One Percentage Point Increase on Postretirement Benefit Obligation				$ 10
Effect of One Percentage Point Decrease on Postretirement Benefit Obligation				10
Effect of One Percentage Point Increase on Total Service and Interest Cost				1
Effect of One Percentage Point Decrease on Total Service and Interest Cost				$ 0
Annualized individual discount rates based on time period, minimum				6 months
Annualized individual discount rates based on time period, maximum				99 years
Other Postretirement Benefit Plans, Defined Benefit [Member]
Components of net periodic costs [Abstract]
Service cost				$ 1	$ 1	$ 1
Interest cost				10	13	14
Expected return on plan assets				(5)	(6)	(6)
Amortization of transition obligation				0	0	4
Amortization of prior service credit				(4)	(2)	(2)
Amortization of loss				1	3	1
Curtailment				(4)	0	0
Net postretirement benefit cost (credit)				(1)	9	12
Change in Benefit Obligation
Service cost				1	1	1
Interest cost				10	13	$ 14
Amounts Recognized in Balance Sheets
Other liabilities-benefit obligations		$ (129)	$ (173)	(129)	(173)
Net liability, end of year		$ (129)	$ (173)	$ (129)	$ (173)
Maximum [Member]
Actuarial Assumptions
Healthcare cost trend rate assumed for the next year				10.65%	5.50%
Minimum [Member]
Actuarial Assumptions
Healthcare cost trend rate assumed for the next year				5.75%	6.00%
Health Care [Member]
Actuarial Assumptions
Year that the healthcare rate reaches the ultimate trend rate		2,024	2,024	2,024	2,024
Prescription Drug [Member]
Actuarial Assumptions
Year that the healthcare rate reaches the ultimate trend rate		2,024	2,024	2,024	2,024
CenterPoint Energy [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Maximum Limit Of Account Balance In Company Stock, Percentage				25.00%
Number Of Shares In Common Stock Held By Savings Plan		14,216,986		14,216,986
Percentage of investment in common stocks		17.00%		17.00%
[1]	The Postretirement plan was amended during 2016 to change retiree medical coverage, effective January 1, 2017, as follows: (i) members of the IBEW Local Union 66 who retire on or after January 1, 2017, and their dependents, will receive any retiree medical and prescription drug coverage exclusively through the NECA/IBEW Family Medical Care Plan pursuant to the terms of the renegotiated collective bargaining agreement entered into in May 2016; and (ii) Medicare eligible post-65 retirees will receive coverage through a Medicare Advantage Program, an insured benefit, in lieu of the previous self-insured benefit. These changes resulted in a reduction in our Postretirement Plan liability of $65 million as of December 31, 2016.
[2]	In May 2016, Houston Electric entered into a renegotiated collective bargaining agreement with the IBEW Local Union 66 and amended the Houston Electric Union Postretirement Trust. The amendment resulted in a split of the trust into two segregated and restricted accounts, one holds assets for the benefit of current, retired on or before December 31, 2016, union retirees and one holds assets for the benefit of post-2016 union retirees who are now covered exclusively by the NECA/IBEW Family Medical Care Plan. Accordingly, $20 million was transferred to the account for post-2016 union retirees.

Employee Benefit Plans Plan Ass

Employee Benefit Plans Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Pension plan assets, fair value	$ 88		$ 110		$ 115
Postemployment Benefits [Abstract]
Postemployment Benefits, Period Credit			1
Postemployment Benefits, Period Expense	3				1
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Benefit expense related to deferred compensation plans	1		1		$ 1
Equity Funds [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Pension plan assets, fair value	$ 88	[1]	110	[2]
U.S. Equity [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum	13.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum	23.00%
International Equity [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum	3.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum	13.00%
Fixed Income [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum	69.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum	79.00%
Cash and Cash Equivalents [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Defined Benefit Plan, Target Plan Asset Allocations Range Minimum	0.00%
Defined Benefit Plan, Target Plan Asset Allocations Range Maximum	2.00%
Fair Value, Inputs, Level 1 [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Pension plan assets, fair value	$ 88		110
Fair Value, Inputs, Level 1 [Member] | Equity Funds [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Pension plan assets, fair value	88	[1]	110	[2]
Fair Value, Inputs, Level 2 [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Pension plan assets, fair value	0		0
Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Pension plan assets, fair value	0	[1]	0	[2]
Fair Value, Inputs, Level 3 [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Pension plan assets, fair value	0		0
Fair Value, Inputs, Level 3 [Member] | Equity Funds [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Pension plan assets, fair value	0	[1]	$ 0	[2]
Other Postretirement Benefit Plans, Defined Benefit [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Defined Benefit Plan, Estimated future contributions in the next fiscal year	9
Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
Postretirement benefit payments - 2017	11
Postretirement benefit payments - 2018	12
Postretirement benefit payments - 2019	13
Postretirement benefit payments - 2020	15
Postretirement benefit payments - 2021	16
Postretirement benefit payments - 2022-2026	$ 90
International Equity [Member] | Equity Funds [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations	8.00%		8.00%
Fixed Income Funds [Member] | Equity Funds [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations	73.00%		73.00%
U.S. Equity [Member] | Equity Funds [Member]
Schedule Of Fair Value Of Financial Assets For Pension And Postretirement Benefits [Line Items]
Defined Benefit Plan, Actual Plan Asset Allocations	19.00%		19.00%
Benefit Obligation [Member]
Postemployment Benefits [Abstract]
Postemployment benefit obligations	$ 6		$ 6
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
Other non-qualified plans benefit obligations deferred compensation	$ 11		$ 11
[1]	73% of the amount invested in mutual funds was in fixed income securities; 19% was in U.S. equities and 8% was in international equities.
[2]	73% of the amount invested in mutual funds was in fixed income securities; 19% was in U.S. equities and 8% was in international equities.

Employee Benefit Plans Other Em

Employee Benefit Plans Other Employee Matters (Details)	12 Months Ended
	Dec. 31, 2016
Concentration Risk [Line Items]
Number of full-time employees	2,738
Employees Subject To Collective Bargaining Agreements [Member] | Labor Force Concentration Risk [Member] | Number of Employees [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	51.00%

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Carrying Amount [Member]
Fair Value Assets and Liabilities Measured on Recurring Basis Disclosure Items [Line Items]
Long-term debt, including current portion	$ 4,865	$ 4,859
Fair Value [Member]
Fair Value Assets and Liabilities Measured on Recurring Basis Disclosure Items [Line Items]
Long-term debt, including current portion	5,079	5,086
Fair Value, Inputs, Level 1 [Member]
Fair Value Assets and Liabilities Measured on Recurring Basis Disclosure Items [Line Items]
Investments, including money market funds	59	32
Fair Value, Inputs, Level 2 [Member]
Fair Value Assets and Liabilities Measured on Recurring Basis Disclosure Items [Line Items]
Assets or liabilities	0	0
Fair Value, Inputs, Level 3 [Member]
Fair Value Assets and Liabilities Measured on Recurring Basis Disclosure Items [Line Items]
Assets or liabilities	$ 0	$ 0

Related Party Transactions an37

Related Party Transactions and Major Customers (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Investments in Money Pool	$ 96								$ 96
Money Pool Borrowings					$ 312					$ 312
Debt, Weighted Average Interest Rate	1.04%								1.04%
Interest Income (Expense) Net, Related Party									$ (4)	(1)	$ (1)
Cash Dividends Paid to Parent Company									135	252	0
Proceeds from Contributions from Parent									374	0	90
Revenues	$ 731	$ 909	$ 763	$ 656	$ 697	$ 827	$ 705	$ 617	3,059	2,846	2,846
Affiliates of NRG Energy, Inc. [Member]
Related Party Transaction [Line Items]
Revenues									698	741	735
Affiliates of Energy Future Holdings Corp. [Member]
Related Party Transaction [Line Items]
Revenues									220	220	189
Operation And Maintenance Expense [Member] | CenterPoint Energy [Member]
Related Party Transaction [Line Items]
Corporate service charges									179	176	159
Operation And Maintenance Expense [Member] | CERC Corp [Member]
Related Party Transaction [Line Items]
Corporate service charges									7	6	5
Related Party Transaction, Other Revenues from Transactions with Related Party									$ (15)	$ (18)	$ (17)

Long-term Debt (Details)

Long-term Debt (Details) $ in Millions		Jan. 12, 2017USD ($)	Dec. 31, 2016USD ($)	Aug. 08, 2016USD ($)	May 13, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Debt Issuance Costs, Noncurrent, Net			$ (23)			$ (23)	$ (21)
Debt Instrument, Unamortized Discount (Premium), Net			(9)			(9)	(8)
Long-term Debt, Excluding Current Maturities			4,454			4,454	4,468
Long-term Debt, Current Maturities	[1]		411			411	391
Line of Credit Facility [Abstract]
Size of Credit Facility			$ 300			$ 300	300
Debt, Weighted Average Interest Rate			1.04%			1.04%
Annual maturities of long-term debt [Abstract]
2,017			$ 0			$ 0
2,018			0			0
2,019			0			0
2,020			0			0
2,021			402			402
Bonds Pollution Control Due Range 2 [Member]
Debt Instrument [Line Items]
Retirement Of Bonds Held For Remarketing			56
Bonds General Mortgage Due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount					$ 300
Debt Instrument, Interest Rate, Stated Percentage					1.85%
Debt Instrument, Maturity Date					May 13, 2021
Bonds General Mortgage Due 2026 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 300
Debt Instrument, Interest Rate, Stated Percentage				2.40%
Debt Instrument, Maturity Date				Aug. 8, 2026
Securitization Bonds [Member]
Annual maturities of long-term debt [Abstract]
2,017			411			411
2,018			434			434
2,019			458			458
2,020			231			231
2,021			211			211
Bank Loans
Debt Instrument [Line Items]
Long-term Debt, Gross, Noncurrent			0			0	200
Long-term Debt, Gross, Current	[1]		0			0	0
First mortgage bonds 9.15% due 2021
Debt Instrument [Line Items]
Long-term Debt, Gross, Noncurrent			102			102	102
Long-term Debt, Gross, Current	[1]		$ 0			$ 0	0
Debt Instrument, Interest Rate, Stated Percentage			9.15%			9.15%
Annual maturities of long-term debt [Abstract]
Secured Debt			$ 102			$ 102
Replacement Fund Requirements			240			240
Sinking Fund Requirements			1.6			1.6
General mortgage bonds 1.85% to 6.95% due 2021 to 2044 (3)
Debt Instrument [Line Items]
Long-term Debt, Gross, Noncurrent	[2]		2,512			2,512	1,912
Long-term Debt, Gross, Current	[1],[2]		0			0	0
Annual maturities of long-term debt [Abstract]
Secured Debt			2,600			2,600
System restoration bonds 3.46% to 4.243% due 2018 to 2022
Debt Instrument [Line Items]
Long-term Debt, Gross, Noncurrent			312			312	365
Long-term Debt, Gross, Current	[1]		53			53	50
Transition bonds 0.901% to 5.302% due 2017 to 2024
Debt Instrument [Line Items]
Long-term Debt, Gross, Noncurrent			1,560			1,560	1,918
Long-term Debt, Gross, Current	[1]		358			358	341
Revolving Credit Facility [Member]
Line of Credit Facility [Abstract]
Loans Outstanding	[3]		$ 0			$ 0	$ 200
Debt, Weighted Average Interest Rate							1.64%
Line of Credit [Member]
Line of Credit Facility [Abstract]
Percentage on limitation of debt to total capitalization under covenant (in hundredths)	[4]					65.00%
Ratio of Indebtedness to Net Capital	[5]		0.474			0.474
Percentage on limitation of debt to total capitalization under covenant amended (in hundredths)						70.00%
Restoration Cost Expected Cost						$ 100
Consecutive Period for System Restoration Costs to Exceed $100 million (in months)						12
Letter of Credit [Member]
Line of Credit Facility [Abstract]
Loans Outstanding			$ 4			$ 4	$ 4
London Interbank Offered Rate (LIBOR) [Member] | Line of Credit [Member]
Line of Credit Facility [Abstract]
Line of Credit Facility, Interest Rate Description	[6]					1.125%
Subsequent Event [Member] | Bonds General Mortgage Due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount		$ 300
Debt Instrument, Interest Rate, Stated Percentage		3.00%
Debt Instrument, Maturity Date		Jan. 12, 2027
April [Member] | Treasury Lock [Member]
Debt Instrument [Line Items]
Derivative, Notional Amount			150			$ 150
June and July [Member] | Treasury Lock [Member]
Debt Instrument [Line Items]
Derivative, Notional Amount			$ 300			300
January [Member] | Treasury Lock [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Derivative, Notional Amount		$ 150
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net		$ (0.5)
Cash Flow Hedging [Member]
Debt Instrument [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net						$ 1.1
Minimum [Member] | General mortgage bonds 1.85% to 6.95% due 2021 to 2044 (3)
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			1.85%			1.85%
Minimum [Member] | System restoration bonds 3.46% to 4.243% due 2018 to 2022
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			3.46%			3.46%
Minimum [Member] | Transition bonds 0.901% to 5.302% due 2017 to 2024
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			0.901%			0.901%
Maximum [Member] | General mortgage bonds 1.85% to 6.95% due 2021 to 2044 (3)
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			6.95%			6.95%
Maximum [Member] | System restoration bonds 3.46% to 4.243% due 2018 to 2022
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			4.243%			4.243%
Maximum [Member] | Transition bonds 0.901% to 5.302% due 2017 to 2024
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			5.302%			5.302%
[1]	Includes amounts due or scheduled to be paid within one year of the date noted.
[2]	Debt issued as collateral is excluded from the financial statements because of the contingent nature of the obligation.
[3]	Weighted average interest rate was 1.64% as of December 31, 2015.
[4]	The financial covenant limit will temporarily increase from 65% to 70% if Houston Electric experiences damage from a natural disaster in its service territory and Houston Electric certifies to the administrative agent that Houston Electric has incurred system restoration costs reasonably likely to exceed $100 million in a consecutive twelve-month period, all or part of which Houston Electric intends to seek to recover through securitization financing. Such temporary increase in the financial covenant would be in effect from the date Houston Electric delivers its certification until the earliest to occur of (i) the completion of the securitization financing, (ii) the first anniversary of Houston Electric’s certification or (iii) the revocation of such certification.
[5]	As defined in the revolving credit facility agreement, excluding Securitization Bonds.
[6]	Based on current credit ratings.

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current Income Tax Expense [Abstract]
Federal	$ 165	$ 106	$ 136
State	18	21	19
Total current expense	183	127	155
Deferred Income Tax Expense (Benefit) [Abstract]
Federal	(34)	18	(24)
Total deferred expense (benefit)	(34)	18	(24)
Total income tax expense	149	145	131
Income Tax Reconciliation [Abstract]
Income before income taxes	$ 425	$ 406	$ 383
Federal statutory income tax rate	35.00%	35.00%	35.00%
Expected federal income tax expense	$ 149	$ 142	$ 134
Increase (decrease) in tax expense resulting from:
State income tax expense, net of federal income tax	12	14	12
Other, net	(12)	(11)	(15)
Total	0	3	(3)
Total income tax expense	$ 149	$ 145	$ 131
Effective tax rate	35.00%	36.00%	34.00%
Tax benefits recognized			$ (6)
Deferred tax assets:
Benefits and compensation	$ 47	$ 69
Loss and credit carryforwards	0	6
AROs	12	13
Other	4	7
Total deferred tax assets	63	95
Deferred tax liabilities:
Property, Plant and Equipment	1,541	1,447
Regulatory assets/liabilities, net	525	680
Total deferred tax liabilities	2,066	2,127
Net deferred tax liabilities	$ 2,003	$ 2,032

Commitments and Contingencies (

Commitments and Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2,017	$ 1
2,018	1
2,019	1
2,020	1
2,021	1
Operating lease rent expense	$ 1	$ 1	$ 1

Unaudited Quarterly Informati41

Unaudited Quarterly Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues	$ 731	$ 909	$ 763	$ 656	$ 697	$ 827	$ 705	$ 617	$ 3,059	$ 2,846	$ 2,846
Operating income	132	258	158	79	105	244	158	101	627	608	596
Net income	$ 52	$ 136	$ 71	$ 17	$ 37	$ 124	$ 69	$ 31	$ 276	$ 261	$ 252