Long-term Purchase Commitment [Table Text Block] Long-term Purchase Commitment [Table Text Block] Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Municipal bonds [Member] US States and Political Subdivisions Debt Securities [Member] Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Change in benefit obligation [Roll Forward] Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Commitments and Contingencies [Text Block] Commitments and Contingencies Disclosure [Text Block] Related Party [Axis] Related Party [Axis] Series A Preferred Stock [Member] Series A Preferred Units [Member] Series A Preferred Stock [Member] Interest expense and other finance charges Interest Expense Interest and Debt Expense Preferred stock convertible threshold (in days) Preferred stock convertible threshold (in days) Threshold period of specified days within which entity has option to redeem preferred stock. Change in plan assets [Rollforward] Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] 9.15% First Mortgage Bonds due 2021 9.15% First Mortgage Bonds Due 2021 [Member] 9.15% First Mortgage Bonds Due 2021 [Member] Current regulatory assets (1) Regulatory Assets, Current LIFO Inventory Amount LIFO Inventory Amount Other comprehensive loss from unconsolidated affiliates, net of tax OCI, Equity Method Investment, after Tax Unamortized Issuance Costs Debt Issuance Costs, Noncurrent, Net Increase (Decrease) in Other Accrued Unbilled Revenues Increase (Decrease) In Contract With Customer, Asset, Other Accrued Unbilled Receivables Increase (Decrease) In Contract With Customer, Asset, Other Accrued Unbilled Receivables Preferred units - unconsolidated affiliate Cost Method Investments Proceeds from sale of marketable securities Proceeds from sale and maturity of marketable securities Proceeds from Sale and Maturity of Marketable Securities State law change, net of federal income tax Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Net amount recognized in accumulated other comprehensive loss (gain) Accumulated Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Tax Range [Domain] Statistical Measurement [Domain] LIABILITIES AND SHAREHOLDERS’ EQUITY Liabilities and Equity [Abstract] 2025 Lessor, Operating Lease, Payment to be Received, Year Five Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Summarized Financial Information on Investment in Time Warner Securities and Indexed Debt Security Obligation [Table Text Block] Schedule of Indexed Debt Securities and Marketable Securities [Table Text Block] Schedule of Indexed Debt Securities and Marketable Securities [Table Text Block] Indexed Debt Securities [Abstract] Indexed Debt Securities [Abstract] Indexed Debt Securities [Abstract] U.S. Equity [Member] U.S. Equity [Member] U.S. Equity [Member] Preferred Stock [Member] Series A Preferred Units [Member] Preferred Stock [Member] Fixed Income [Member] Fixed Income [Member] Fixed Income [Member] Security Exchange Name Security Exchange Name Debt Instrument, Initial Interest Rate, Stated Percentage Debt Instrument, Initial Interest Rate, Stated Percentage Debt Instrument, Initial Interest Rate, Stated Percentage Fair value of plan assets, beginning of year Fair value of plan assets, end of year Plan assets, fair value Defined Benefit Plan, Plan Assets, Amount Change in Accounts Receivable [Roll Forward] Change in Accounts Receivable [Roll Forward] Change in Accounts Receivable [Roll Forward] Proceeds from long-term debt Proceeds from Issuance of Long-term Debt Capital expenditures Capital Expenditure, Discontinued Operations Total current liabilities Current liabilities Liabilities, Current Accounts Receivable and Allowance for Doubtful Accounts Accounts Receivable [Policy Text Block] Other Information Related To Leases [Table Text Block] Other Information Related To Leases [Table Text Block] Other Information Related To Leases [Table Text Block] Curtailment Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment Performance Awards [Member] Performance Shares [Member] Prepaid expense and other current assets Prepaid Expense and Other Assets, Current Weighted average grant date fair value, nonvested, beginning of period (in dollars per share) Weighted average grant date fair value, nonvested, end of period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Variable Rate [Domain] Variable Rate [Domain] Pension benefit payments 2024 Defined Benefit Plan, Expected Future Benefit Payment, Year Five Debt component of ZENS Debt Component Of Zens Abstract ASSETS Assets [Abstract] Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Investment, Name [Axis] Investment, Name [Axis] Accounting Policies [Abstract] Accounting Policies [Abstract] Indexed debt securities derivatives transferred out of level 3 Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers out of Level 3 Cash and Cash Equivalents and Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Issuances related to benefit and investment plans Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture Accounts payable - affiliated companies Due to Related Parties, Current Operating cash flows from operating leases included in the measurement of lease liabilities Operating Lease, Payments 2023 Long-Term Debt, Maturity, Year Three Weighted Average Useful Lives Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Enable Series A Distribution Rate Enable Series A Distribution Rate Enable Series A Distribution Rate Chicago Stock Exchange Chicago Stock Exchange [Member] Chicago Stock Exchange [Member] 2021 Lessee, Operating Lease, Liability, to be Paid, Year One Lease Income Lease Income 2024 Lessee, Operating Lease, Liability, to be Paid, Year Four Expenditures for Long-Lived Assets Capital Expenditures for Long-Lived Assets Capital Expenditures for Long-Lived Assets Natural gas expenses, including transportation and storage costs (1) Property, plant and equipment from parent (2) Related Party Transaction, Purchases from Related Party Fair Value, Assets Measured on a Recurring Basis [Table Text Block] Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] CenterPoint Energy’s basis difference (1) Equity Method Investment, Basis Difference This represents the basis difference of an equity method investment. Unrecognized compensation cost related to non-vested performance and stock awards Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount Excess deferred income tax amortization Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amortization, Amount Change in Other Accrued Unbilled Revenues [Roll Forward] Change in Other Accrued Unbilled Revenues [Roll Forward] Change in Other Accrued Unbilled Revenues [Roll Forward] Pension and Other Postretirement Plans [Member] Other Pension, Postretirement and Supplemental Plans [Member] State Current State and Local Tax Expense (Benefit) Guarantor Obligations, Maximum Exposure, Undiscounted Guarantor Obligations, Maximum Exposure, Undiscounted Deferred tax assets tax credit carryforwards Tax Credit Carryforward, Amount Other Non-Qualified Plans [Abstract] Other Nonqualified Plan Abstract Preferred Stock Preferred Stock, Value, Issued Transaction costs associated with the Merger Transaction costs associated with the Merger Costs incurred direct costs of the business combination including legal, accounting, and other costs incurred to consummate the business acquisition. Diluted earnings (loss) per common share - continuing operations Income (Loss) from Continuing Operations, Per Diluted Share Amortization of intangible assets in Non-utility cost of revenues Amortization of intangible assets, discontinued operations Amortization of intangible assets, discontinued operations Management rights ownership percentage Management Rights Ownership Percentage Represents the percentage of management rights in the general partner of Enable Regulatory liabilities Non-current regulatory liabilities Regulatory Liability, Noncurrent Diluted earnings (loss) per common share - discontinued operations Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share Common stock, $0.01 par value Common Stock, Par or Stated Value Per Share Benefit Plan Contributions [Table Text Block] Benefit Plan Contributions [Table Text Block] Benefit Plan Contributions [Table Text Block] Non-utility Investments [Member] Non-utility Investments [Member] Non-utility Investments [Member] Pension benefit payments 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Three Other Other Liabilities, Noncurrent Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Operating Activities [Axis] Operating Activities [Axis] Investment in marketable securities ZENS-Related Securities ZENS-Related Securities Marketable Securities, Current Percentage Reduction of Dividend or Distribution Amount Percentage Reduction of Dividend or Distribution Amount Percentage Reduction of Dividend or Distribution Amount Replacement fund requirements to be satisfied in 2018 Replacement Fund Requirements This element represents those amounts to be set aside for the repair and replacement of real or personal property in the foreseen future. Such amount may be satisfied by certification of property additions. Securitization Bonds [Member] Transition And System Restoration Bonds [Member] Represents the amount of transition and system restoration bonds maturing. Accrued Unbilled Revenues Unbilled Receivables, Current VCC [Member] VCC [Member] Vectren Capital Corp Fair Value, Measurement Frequency [Domain] Measurement Frequency [Domain] Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Electric Electric [Member] Electric reportable segment consists of electric transmission and distribution services in the Texas Gulf Coast area and electric transmission and distribution services primarily to southwestern Indiana and includes power generation and wholesale power operations. Unrecognized tax benefits assumed through the Merger Unrecognized Tax Benefits, Increase Resulting from Acquisition Concentration Risk, Percentage Concentration Risk, Percentage Legal, Environmental and Other Matters Loss Contingency, Information about Litigation Matters [Abstract] CenterPoint Energy Houston Electric 2019 Rate Case [Member] CenterPoint Energy Houston Electric 2019 Rate Case [Member] CenterPoint Energy Houston Electric 2019 Rate Case [Member] Current portion of other long-term debt Other Long-term Debt, Current Fair value of plan assets Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets Statement [Line Items] Statement [Line Items] Class of Stock [Domain] Class of Stock [Domain] Statement [Table] Statement [Table] Benefits and compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits Face amount of each indexed debt security notes issued by CenterPoint Energy in September 1999 Dollar Face Amount Of Individual Note The dollar denomination for each individual note Interest cost (2) Defined Benefit Plan, Interest Cost Range [Axis] Statistical Measurement [Axis] Mutual funds [Member] Equity Funds [Member] Preferred equity Equity Method Investment, Summarized Financial Information, Preferred Equity Amount of preferred equity attributable to the equity method investment of the entity. Interest Income Interest Income, Other Weighted Average [Member] Weighted Average [Member] Investments in Equity Securities (CenterPoint Energy and CERC) Marketable Securities, Policy [Policy Text Block] Entity Small Business Entity Small Business Principles of Consolidation Consolidation, Policy [Policy Text Block] Ratio of indebtedness to net capital Ratio of Indebtedness to Net Capital Variable lease income Operating Lease, Variable Lease Income Schedule of Regulatory Assets and Liabilities [Line Items] Schedule Of Regulatory Assets And Liabilities [Line Items] -- None. No documentation exists for this element. -- Short-term Borrowings and Long-term Debt [Text Block] Debt Disclosure [Text Block] Fair value of plan assets measurement [Domain] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Target Allocation of Plan Assets [Table Text Block] Target Allocation of Plan Assets [Table Text Block] Tabular presentation of the weighted average allocation targets maintained Revenues Disposal Group, Including Discontinued Operation, Revenue First Mortgage [Member] First Mortgage [Member] Cost of sales, excluding depreciation and amortization Cost of Revenue Pension and Other Postretirement Plans Costs [Member] Pension and Other Postretirement Plans Costs [Member] Estimated capital expenditure to clean ash ponds Estimated capital expenditure to clean ash ponds Estimated Capital Expenditure to Clean Ash Ponds Amendment Flag Amendment Flag Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued Shares authorized for issuance under long-term incentive plans (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Non-qualified Pension Plan [Member] Other Pension Plan [Member] Energy Products and Services [Member] Energy Products Or Services [Member] Represents revenue from energy products and services Measurement Frequency [Axis] Measurement Frequency [Axis] Non-current liabilities held for sale Total non-current liabilities held for sale Disposal Group, Including Discontinued Operation, Liabilities, Noncurrent Series B Preferred Stock [Member] Series B Preferred Stock [Member] Subsidiary of CenterPoint Energy equity holdings [Domain] Financial Instruments [Domain] Estimated Fair Value of Financial Instruments, Debt Instruments [Table Text Block] Fair Value, by Balance Sheet Grouping [Table Text Block] Expected return on plan assets (2) Defined Benefit Plan, Expected Return (Loss) on Plan Assets Equity Method and Investments Without a Readily Determinable Fair Value (CenterPoint Energy) Equity Method Investments [Policy Text Block] 2024 Purchase Obligation, to be Paid, Year Four Portion at Fair Value Measurement [Member] Fair Value Measurement [Domain] Accounting Standards Update 2018-02 Accounting Standards Update 2018-02 [Member] Natural gas expense Discontinued Operation, Intra-Entity Amounts, Discontinued Operation after Disposal, Expense Accounts payable related to capital expenditures Capital Expenditures Incurred but Not yet Paid Derivative Instruments Derivatives, Policy [Policy Text Block] Subsequent Events [Text Block] Subsequent Events [Text Block] Collective Bargaining Arrangement [Axis] Collective-Bargaining Arrangement [Axis] Regulatory liabilities Deferred Tax Assets, Regulatory Assets and Liabilities Comprehensive income (loss) ComprehensiveIncomeNetofTaxBeforePreferredStockDiv Total comprehensive income before preferred stock dividend requirements. Property, Plant and Equipment, Type [Axis] Long-Lived Tangible Asset [Axis] Revenues by Products and Services [Table Text Block] Revenue from External Customers by Products and Services [Table Text Block] Bad debt reserve Accounts Receivable, Allowance for Credit Loss, Current Interest expense on Securitization Bonds Interest on Transition and System Restoration Bonds Interest and debt related expenses associated with transition and system restoration bonds. Income Statement Location [Domain] Derivative Instruments, Gain (Loss) by Income Statement Location [Domain] Income Statement Location [Domain] 2022 Lessee, Operating Lease, Liability, to be Paid, Year Two State and Local Jurisdiction State and Local Jurisdiction [Member] VIE Securitization Bonds, net Transition And System Restoration Bonds Long Term Debt Non Current Carrying value as of the balance sheet date of transition and system restoration bond debt (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion. Unprotected excess deferred income tax Unprotected excess deferred income tax Unprotected excess deferred income tax resulting from the TCJA Preferred Stock Incremental Common Shares Attributable to Dilutive Effect of Conversion of Preferred Stock Lease, Cost [Table Text Block] Lease, Cost [Table Text Block] Make-Whole Amount Make-Whole Amount Make-Whole Amount Exchange [Domain] Exchange [Domain] 2023 Lessee, Operating Lease, Liability, to be Paid, Year Three Other Other Assets, Noncurrent CenterPoint Energy’s ownership interest in Enable partners’ equity Equity Method Investment, Underlying Equity in Net Assets Total liabilities Financial Liabilities Fair Value Disclosure Concentration Risk [Table] Concentration Risk [Table] Benefit obligations Disposal Group, Including Discontinued Operation, Pension Plan Benefit Obligation, Noncurrent Income From Continuing Operations Income (loss) from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent IGC IGC [Member] IGC Other Employee Matters [Table Text Block] Other Employee Matters [Table Text Block] Other Employee Matters [Table Text Block] Total Assets Total Assets Assets Related Party Transactions (Houston Electric and CERC) [Text Block] Related Party Transactions Disclosure [Text Block] Exercise Price Range [Domain] Exercise Price Range [Domain] International government bonds [Member] Debt Security, Government, Non-US [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in September 2021 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringinSeptember2021 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringinSeptember2021 [Member] Nonvested, beginning of period (in shares) Nonvested, end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Maximum incentive distribution right Incentive Distribution Right, Maximum Maximum additional incentive right to the general partner with quarterly distribution per unit exceeding $0.330625 Catastrophic Event [Axis] Catastrophic Event [Axis] Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Axis] Reporting Unit [Domain] Reporting Unit [Domain] Construction backlog [Member] Order or Production Backlog [Member] Amortization of prior service cost (2) Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Infrastructure Services Disposal Group [Member] Infrastructure Services Disposal Group [Member] Infrastructure Services Disposal Group Defined Benefit Plan, Estimated Future Benefit Payments [Abstract] Defined Benefit Plan, Expected Future Benefit Payment [Abstract] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Benefit expense related to deferred compensation plans Deferred Compensation Arrangement with Individual, Compensation Expense Other Disposal Group, Including Discontinued Operation, Other Liabilities, Noncurrent Cost of Sales [Member] Non-utility cost of revenues [Member] Cost of Sales [Member] Long-term debt: Long-term Debt, by Current and Noncurrent [Abstract] Maximum Number Of Times Annual Salary Included In Severance Benefits Maximum Number Of Times Annual Salary Included In Severance Benefits Maximum number of times annual base salary included in severance benefits for certain officers in a change of control (in number of times) Derivative component of ZENS Derivative Component Of Zens Abstract Weather Hedge Term Weather Hedge Term Period of time used as the basis for weather hedges entered into by the company. Environmental Remediation Site [Domain] Environmental Remediation Site [Domain] Estimated Fair Value of Financial Instruments Additional Fair Value Elements [Abstract] Other [Member] Other Intangible Assets [Member] Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Goodwill impairment and loss from reclassification to held for sale Goodwill impairment and loss from reclassification to held for sale Goodwill impairment and loss from reclassification to held for sale Additional first mortgage bonds and general mortgage bonds that could be issued Additional first mortgage bonds and general mortgage bonds that could be issued Amount of additional first mortgage bonds and general mortgage bonds that could be issued on the basis of retired bonds and 70% of property additions as of the balance sheet date. Prescription drug cost trend rate assumed for the next year - Pre-65 Defined Benefit Plan Prescription Drug Cost Trend Rate Assumed For Next Fiscal Year The assumed prescription drug cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of prescription drugs currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status. Interest crediting rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Weighted-Average Interest Crediting Rate Goodwill impairment Effective Income Tax Rate Reconciliation, Deduction, Other, Amount Retirement Plan Type [Axis] Retirement Plan Type [Axis] Electric Transmission & Distribution [Member] Electric Transmission & Distribution [Member] Segment information for the Electric Transmission & Distribution segment which engages in the electric transmission and distribution business in the Texas Gulf Coast area. Less: Interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Accumulated benefit obligation for all defined benefit pension plans Defined Benefit Plan, Accumulated Benefit Obligation Participant contributions Defined Benefit Plan, Plan Assets, Contributions by Plan Participant Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Discontinued Operations, Disposed of by Means Other than Sale, Spinoff [Member] Discontinued Operations, Disposed of by Means Other than Sale, Spinoff [Member] Number of surety bond obligations outstanding Number of surety bond obligations outstanding Represents the absolute number of surety bonds the wholly owned subsidiary has outstanding in its role as general contractor 2025 Purchase Obligation, to be Paid, Year Five Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Regulated Operations [Abstract] Regulated Operations [Abstract] Inventory Increase (Decrease) in Inventories Debt, Weighted Average Interest Rate Debt, Weighted Average Interest Rate Environmental Improvement Revenue Bonds, Mount Vernon, 0.875%, Series 2015 [Member] Environmental Improvement Revenue Bonds, Mount Vernon, 0.875%, Series 2015 [Member] Environmental Improvement Revenue Bonds, Mount Vernon, 0.875%, Series 2015 Number of states in which entity operates Number of States in which Entity Operates Preferred Units by Name [Axis] Preferred Units by Name [Axis] Preferred Units by Name [Axis] Summary of nonvested shares [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Regulatory Agency [Axis] Regulatory Agency [Axis] Depreciation and Amortization [Table Text Block] Depreciation And Amortization [Table Text Block] This element can be used to encapsulate the entire disclosure for depreciation and amortization expense for the period. Effective Income Tax Rate Reconciliation, Other Adjustments [Domain] Effective Income Tax Rate Reconciliation, Other Adjustments [Domain] [Domain] for Effective Income Tax Rate Reconciliation, Other Adjustments [Axis] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Income allocated to preferred shareholders Less: Preferred stock dividend requirement (Note 13) Preferred Stock Dividends and Other Adjustments Gains (Losses) in Other Income (Expense) [Member] Nonoperating Income (Expense) [Member] Other, net Other Operating Activities, Cash Flow Statement 2022 Purchase Obligation, to be Paid, Year Two Asset Class [Axis] Asset Class [Axis] Basic earnings (loss) per common share - continuing operations Income (Loss) from Continuing Operations, Per Basic Share Accrued unbilled revenues Disposal Group, Including Discontinued Operation, Accrued Unbilled Revenues Disposal Group, Including Discontinued Operation, Accrued Unbilled Revenues Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Common Stock, Shares, Outstanding Balance, beginning of year Balance, end of year Common Stock, Shares, Outstanding Investment in unconsolidated affiliates CenterPoint Energy’s equity method investment in Enable Equity Method Investments Deferred tax assets: Deferred Tax Assets, Net [Abstract] Income Tax Disclosure [Abstract] Income Tax Disclosure [Abstract] Loss on dilution, net of proportional basis difference recognition Dilution Loss, Equity Method Investment Dilution Loss, Equity Method Investment Revolving Credit Facility [Member] Revolving Credit Facility [Member] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Income (Loss) from Continuing Operations Before Income Taxes Income (loss) before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest ERCOT Loan, COVID-19 ERP ERCOT Loan, COVID-19 ERP ERCOT Loan, COVID-19 ERP Integration costs Business Combination, Integration Related Costs Number of days until commercial paper maturity Number of days until commercial paper maturity Number of days until commercial paper maturity. Total regulatory assets and liabilities, net Net Regulatory Assets Acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Common Stock, Shares Authorized Common Stock, Shares Authorized Record Date Distribution Made to Limited Partner, Date of Record Restricted stock (2) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Years to resolve contingency Site Contingency, Years to Resolve Contingency This represents the estimated years necessary to resolve the contingency. Property, Plant and Equipment, Gross Property, Plant and Equipment, Gross Federal Deferred Federal Income Tax Expense (Benefit) Pension benefit payments 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year Two Financial Data for Business Segments [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Funded status, end of year Defined Benefit Plan, Funded (Unfunded) Status of Plan Equity in earnings of unconsolidated affiliate, net Investments in and Advances to Affiliates, at Fair Value, Period Increase (Decrease) Statements of Consolidated Income Income Statement [Abstract] Income Statement [Abstract] AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] Asset Retirement Obligation Addition from Merger with Vectren Asset Retirement Obligation Addition from Merger with Vectren Asset Retirement Obligation Addition from Merger with Vectren Incentive distribution per unit Incentive Distribution, Distribution Per Unit Equity Method Investment's Impairment on an equity method investment Equity Method Investment's Impairment on an equity method investment Enable's Impairment on an equity method investment (Southeast Supply Header) SESH Hurricane Harvey [Member] Hurricane [Member] Schedule of Segment Reporting [Table] Schedule of Segment Reporting Information, by Segment [Table] Variable Interest Entity, Primary Beneficiary [Member] Variable Interest Entity, Primary Beneficiary [Member] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Use of Estimates Use of Estimates, Policy [Policy Text Block] Tax impact of sale of Energy Services and Infrastructure Services Disposal Groups Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation Write-down of natural gas inventory Inventory Write-down, discontinued operations Inventory Write-down, discontinued operations Operation and maintenance agreements and construction backlog [Member] Operation and maintenance agreements and construction backlog [Member] Operation and maintenance agreements and construction backlog [Member] Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Income Tax Authority [Domain] Income Tax Authority [Domain] Basis difference amortization (1) Basis Difference Accretion Gain Basis Difference Accretion Gain Postemployment Benefits, Period Expense Postemployment Benefits, Period Expense Percentage of sales that trigger right of first refusal Sale of Units, Percentage, Trigger Right of First Refusal Sale of more than this percentage of aggregated common and subordinated units owned are subject to mutual rights of first offer and first refusal. Equity Method Investment Carrying Value Per Unit Equity Method Investment Carrying Value Per Unit The carrying value per unit of an equity method investment at the balance sheet date. Schedule of Assumptions Used [Table Text Block] Defined Benefit Plan, Assumptions [Table Text Block] Consolidated Entities [Axis] Consolidated Entities [Axis] Corporate equities Fair Value Assets Measured On Recurring Basis Corporate Equities This element represents a certain statement of financial position asset caption which represents a class of assets, or which may include an individual asset, measured at fair value on a recurring basis. Net operating loss carryback Recognized tax benefit from changes in tax laws Recognized tax benefit from changes in tax laws Federal income tax rate reduction Tax Benefit From Remeasurement of Deferred Taxes Due to Tax Reform Represents the tax benefit resulting from the remeasurement of deferred taxes due to tax reform. Scenario, Unspecified [Domain] Scenario [Domain] Consolidation Items [Domain] Consolidation Items [Domain] Subordinated Debt ZENS Member ZENS due 2029 (2) Subordinated Debt ZENS Member Issued debt obligation as zero-premium exchangeable subordinated notes. Obligation is bifurcated between a debt component and an embedded derivative component. Exchangeable for cash at any time at the option of the holder, and as such are classified as a current portion of long-term debt. Goodwill and Other Intangibles (CenterPoint Energy and CERC) [Text Block] Goodwill and Intangible Assets Disclosure [Text Block] Accounts and notes receivable—affiliated companies Due from Related Parties, Current Property, Plant and Equipment, net Property, Plant and Equipment [Abstract] Property, Plant and Equipment [Abstract] Actual investment return Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Common Stock, Capital Shares Reserved for Future Issuance Common Stock, Capital Shares Reserved for Future Issuance Conversion rate per share Convertible Preferred Stock, Shares Issued upon Conversion Property, plant and equipment, net Disposal Group, Including Discontinued Operation, Property, Plant and Equipment, Noncurrent Equity in earnings (loss) of unconsolidated affiliates, net Equity in earnings of unconsolidated affiliates CenterPoint Energy’s equity in earnings (losses), net Income (Loss) from Equity Method Investments Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage Indiana Gas Service Territory [Member] Indiana Gas Service Territory [Member] Represents the areas in Indiana serviced by Indiana Gas Service Derivative Component Of ZENS [Member] Derivative Component Of ZENS [Member] Represents the bifurcated derivative component of the ZENS obligation Hedging Designation [Axis] Hedging Designation [Axis] Current liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Net Increase (Decrease) in Cash, Cash Equivalents and Restricted Cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Pension benefit payments 2025 - 2029 Defined Benefit Plan, Expected Future Benefit Payment, after Year Five for Next Five Years Receivables, net Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net Other Income (Expense) [Member] Other Income [Member] Entity [Domain] Entity [Domain] Other Assets: Noncurrent Assets, Other Than Property Plant and Equipment [Abstract] Noncurrent Assets, Other Than Property Plant and Equipment [Abstract] Enable Midstream Partners [Member] Enable Midstream Partners [Member] Enable Midstream Partners, LP Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract] Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract] Restoration Costs Restoration Costs Restoration Costs Discontinued Operation, Additional Disclosures [Abstract] Discontinued Operation, Additional Disclosures [Abstract] Loss and credit carryforwards Deferred Tax Assets, Other Tax Carryforwards Indexed Debt Securities [Line Items] Debt and Equity Securities, FV-NI [Line Items] Weighted Average Useful Lives Property, Plant and Equipment, Useful Life Goodwill [Line Items] Goodwill [Line Items] Contribution from parent Proceeds from Contributions from Parent Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Pension contributions Payment for Pension Benefits Limited Partners' Capital Account, Class [Domain] Limited Partners' Capital Account, Class [Domain] Restricted cash Restricted Cash and Cash Equivalents Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Axis] Other current assets Increase (Decrease) in Other Current Assets Retail Electric Sales [Member] Retail Electric Sales [Member] Retail Electric Sales [Member] Share-Based Compensation, Activity [Table Text Block] Share-based Payment Arrangement, Activity [Table Text Block] Other Regulatory Assets (Liabilities) [Member] Other Regulatory Assets (Liabilities) [Member] Restricted Stock [Member] Restricted Stock [Member] Remaining amounts of regulatory assets for which no return on investment during recovery period is provided Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Share-based Payment Arrangement [Abstract] Capital distribution to parent associated with the sale of CES Payments of Capital Distribution Consolidated Entities [Domain] Consolidated Entities [Domain] Current operating lease liability (2) Operating Lease, Liability, Current Dividends, Distributions, Change [Domain] Dividends, Distributions, Change [Domain] Dividends, Distributions, Change Mortgage backed securities [Member] Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Increase (Decrease) in Accounts Receivable Increase (Decrease) in Accounts Receivable on Contracts with Customers Increase (Decrease) in Accounts Receivable on Contracts with Customers Outstanding obligation related to AMAs Discontinued operation after disposal, purchase obligation Discontinued operation after disposal, purchase obligation Amount of allowed equity return on the true-up balance that was recognized in the period Amount Of Allowed Equity Return Recognized In Period Amount of allowed equity return on the true-up balance that was recognized in the period Discontinued Operation, Alternative Cash Flow Information [Abstract] Discontinued Operation, Alternative Cash Flow Information [Abstract] Income Statement Impact of Derivative Activity [Table Text Block] Derivative Instruments, Gain (Loss) [Table Text Block] Weighted average grant date fair value, forfeited or cancelled (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Other current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets Fair Value of Derivative Instruments [Table Text Block] Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Fair Value Measurements [Text Block] Fair Value Disclosures [Text Block] Regulatory assets Non-current regulatory assets Regulatory Assets, Noncurrent Total Income Tax Reconciliation Change In Tax Expense Represents the increase (decrease) in tax expense resulting from various reconciling items. Limited partner ownership interest Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Name of Major Customer [Domain] Customer [Domain] Pipeline construction and repair services capitalized Discontinued operation, Capitalized fees Discontinued operation, Capitalized fees Current assets held for sale Total current assets held for sale Disposal Group, Including Discontinued Operation, Assets, Current Defined Contribution Plan Disclosures [Table Text Block] Defined Contribution Plan Disclosures [Table Text Block] Natural Gas Distribution Natural Gas Distribution [Member] Segment information for the Natural Gas Distribution segment which consists of intrastate natural gas sales to, and natural gas transportation and distribution for, residential, commercial, industrial and institutional customers. Common Stock, $0.01 par value Common Stock, $0.01 Par Value [Member] Common Stock, $0.01 Par Value [Member] Preferred stock aggregate liquidation preference Preferred stock liquidation preference Preferred Stock, Liquidation Preference, Value Entity Registrant Name Entity Registrant Name Consecutive period for system restoration costs to exceed $100 million (in months) Consecutive Period for System Restoration Costs to Exceed $100 million (in months) Consecutive Period for System Restoration Costs to Exceed $100 million (in months) Subsequent Event Type [Domain] Subsequent Event Type [Domain] Business Acquisition [Line Items] Business Acquisition [Line Items] Weighted-average discount rate - operating leases Operating Lease, Weighted Average Discount Rate, Percent Assets Assets, Fair Value Disclosure [Abstract] Concentration Risk [Line Items] Concentration Risk [Line Items] Non-current assets Assets, Noncurrent Other Information Related to Leases [Abstract] Other Information Related to Leases [Abstract] Other Information Related to Leases [Abstract] Intersegment Eliminations [Member] Intersegment Eliminations [Member] Estimated remediation costs for the Minnesota sites Site Contingency Loss Exposure Estimate of the reasonably possible loss exposure at an individual site. Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract] Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract] Current regulatory liabilities (6) Regulatory Liability, Current Total regulatory assets Regulatory Assets Regulatory Assets Discontinued Operation, Continuing Involvement [Abstract] Discontinued Operation, Continuing Involvement [Abstract] Non-trading derivative assets Disposal Group, Including Discontinued Operation, Non-trading derivative assets Disposal Group, Including Discontinued Operation, Non-trading derivative assets Payment of dividends on Common Stock Payments of Ordinary Dividends, Common Stock Common Collective Trust Funds [Member] Common Collective Trust Funds Member Consists of common collective trust funds invested in equities and fixed income securities. Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Number of warranty obligations outstanding Number of warranty obligations outstanding Represents the number of warranties the wholly owned subsidiary has outstanding in its role as general contractor. Record Date Dividends Payable, Date of Record Income allocated to preferred shareholders Preferred Stock Dividends, Income Statement Impact Preferred stock dividends declared Dividends declared Dividends, Preferred Stock, Cash Common stock issued per share price Shares Issued, Price Per Share Contract Balances [Line Items] Contract Balances [Line Items] [Line Items] for Contract Balances [Table] Adjustments for New Accounting Pronouncements [Axis] Accounting Standards Update [Axis] Cash payments towards outstanding share-based awards Cash payments towards outstanding share-based awards Cash payments towards outstanding share-based awards as a result of the merger close. Preferred Stock, Convertible, Conversion Limit Preferred Stock, Convertible, Conversion Limit Preferred Stock, Convertible, Conversion Limit Other Tax Carryforward [Table] Tax Credit Carryforward [Table] (Increase) decrease in notes receivable–affiliated companies Increase (Decrease) in Notes Receivable, Related Parties Entity Address, Postal Zip Code Entity Address, Postal Zip Code Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Other Deferred Tax Assets Noncurrent Other The tax effect as of the balance sheet date of the amount of estimated future tax deductions arising from other temporary differences not otherwise specified in the taxonomy that are not expected to be resolved within 12 months of the balance sheet date. Percentage of investment in common stocks (in hundredths) Percentage Of Investment In Company Common Stock Percentage of investments held by the Savings Plan in the Entity's common stock. Depreciation and amortization Disposal Group, Including Discontinued Operation, Depreciation and Amortization Workforce Subject to Collective Bargaining Arrangements Expiring in May 2023 Workforce Subject to Collective Bargaining Arrangements Expiring in May 2023 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in May 2023 Goodwill Goodwill Goodwill Business Combination, Separately Recognized Transactions [Table Text Block] Business Combination, Separately Recognized Transactions [Table Text Block] Annualized fee received for retained CES obligation guarantees Annualized fee received for retained CES obligation guarantees Annualized fee received for retained CES obligation guarantees Total Net current period other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Proceeds from (payments of) commercial paper, net Proceeds from (Repayments of) Commercial Paper Taxes accrued Disposal Group, Including Discontinued Operation, Accrued Income Tax Payable, Current Common Stock, Dividends, Per Share, Declared Dividends declared per share Common Stock, Dividends, Per Share, Declared Principal amount of debt issued Debt Instrument, Face Amount VUHI [Member] VUHI [Member] VUHI [Member] Increase (decrease) in notes payable–affiliated companies Increase (Decrease) in Notes Payable, Related Parties Asset backed securities [Member] Asset-backed Securities, Securitized Loans and Receivables [Member] Goodwill by Reportable Segments [Table Text Block] Schedule of Goodwill [Table Text Block] Asset Class [Domain] Asset Class [Domain] Corporate service charges Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party Total assets Assets, Fair Value Disclosure Workforce Subject to Collective Bargaining Arrangements Expiring in March 2021 Workforce Subject to Collective Bargaining Arrangements Expiring in March 2021 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in March 2021 Divestitures (CenterPoint Energy and CERC) Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Preferred Units, Class [Domain] Preferred Units, Class [Domain] Regulatory assets Deferred Tax Liabilities, Regulatory Assets and Liabilities Electric Transmission [Member] Electric Transmission [Member] Transitional Service [Member] Transitional Service [Member] Transitional services costs, including the costs of seconded employees. Customer deposits Contract with Customer, Liability, Current Entities [Table] Entities [Table] Disposal Groups, Including Discontinued Operations Balance Sheet Disposal Groups, Including Discontinued Operations Balance Sheet [Table Text Block] Disposal Groups, Including Discontinued Operations Balance Sheet State Valuation Allowance, net of Federal Income Taxes [Member] State Valuation Allowance, net of Federal Income Taxes [Member] State Valuation Allowance, net of Federal Income Taxes [Member] Derivative Contract [Domain] Derivative, Name [Domain] Derivative Contract [Domain] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Weighted Average Common Shares Outstanding, Diluted Weighted average common shares outstanding - diluted Weighted Average Number of Shares Outstanding, Diluted Letter of Credit [Member] Letter of Credit [Member] LIFO Inventory Schedule of Inventory, Noncurrent [Table Text Block] Variable rate term loan [Member] Variable rate term loan [Member] Variable rate term loan [Member] Public Utilities General Disclosures [Table] Public Utilities General Disclosures [Table] Environmental Costs Environmental Costs, Policy [Policy Text Block] General mortgage bonds 1.85% to 6.95% due 2021 to 2048 Bonds General Mortgage Due Range 1 [Member] Bonds General Mortgage Due Range 1 [Member] Debt Disclosure [Abstract] Debt Disclosure [Abstract] Forfeited or cancelled (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Operation and maintenance Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses First Quarter 2020 [Member] First Quarter 2020 [Member] First Quarter 2020 [Member] Supplemental Income Statement Elements [Abstract] Supplemental Income Statement Elements [Abstract] Other Disposal Group, Including Discontinued Operation, Other Liabilities, Current Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Payments of long-term debt Repayments of Long-term Debt Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Revenue expected to be recognized Revenue, Remaining Performance Obligation, Amount Payment of dividends on preferred stock Payments of Ordinary Dividends, Preferred Stock and Preference Stock Balance, beginning of year Balance, end of year Unrecognized Tax Benefits Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] Common stock Common Stock, Value, Issued Pension benefit payments 2023 Defined Benefit Plan, Expected Future Benefit Payment, Year Four Obligation To Return Cash Received As Collateral From Securities Lending, Defined Benefit Plan, Fair Value, Obligation To Return Cash Received As Collateral From Securities Lending, Represents the fair value of an obligation to return cash received as collateral from securities lending. Document Fiscal Year Focus Document Fiscal Year Focus Tax benefit (expense) Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent 2022 Finite-Lived Intangible Asset, Expected Amortization, Year Two Additional collateral required to be posted if credit risk contingent features triggered (1) Additional Collateral, Aggregate Fair Value Electric Transmission and Distribution [Member] Electric Transmission and Distribution Equipment [Member] Benefit obligation, beginning of year Benefit obligation, end of year Defined Benefit Plan, Benefit Obligation Entity Current Reporting Status Entity Current Reporting Status Merger Exchange Ratio Merger Exchange Ratio Energy Transfer will acquire all of Enable's outstanding equity interest, resulting in the exchange of Enable common units owned by CenterPoint Energy with this ratio Depositary share par value (in dollars per depositary share) Sale of Stock, Price Per Share Debt, Current Debt, Current Fair value of goodwill Goodwill, Fair Value Disclosure Removal Costs [Member] Removal Costs [Member] Related Party Transaction [Axis] Related Party Transaction [Axis] Disposal Groups, Including Discontinued Operations Cash Flow Disposal Groups, Including Discontinued Operations Cash Flow [Table Text Block] Disposal Groups, Including Discontinued Operations Cash Flow Estimated Remaining Exposure Estimated Remaining Exposure Estimated Remaining Exposure Cash paid per share of Vectren common stock at closing of the Merger Business Acquisition, Share Price Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Pipeline construction and repair service charges in operations and maintenance expense Discontinued Operation, Intra-Entity Amounts, Discontinued Operation after Disposal, Pipeline construction and repair charges Discontinued Operation, Intra-Entity Amounts, Discontinued Operation after Disposal, Pipeline construction and repair charges Operation and maintenance agreements [Member] Operation and maintenance agreements [Member] Operation and maintenance agreements [Member] Total leased liabilities Operating Lease, Liability Net deferred tax liabilities Deferred Tax Liabilities, Net Total long-term debt, net Long-term Debt, Term Long-term Debt, Excluding Current Maturities Segment Reporting [Abstract] Segment Reporting [Abstract] Indiana Electric [Member] Indiana Electric [Member] Operations of SIGECO 's electric transmission and distribution services , including power generation and wholesale power operations [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Total shareholders’ equity Balance, beginning of year Balance, end of year Enable partners' equity Stockholders' Equity Attributable to Parent Maximum contractual exposure under Securities Purchase Agreement Discontinued Operation, Amounts of Material Contingent Liabilities Remaining Weighted average interest rate Money Pool Investments Weighted Average Interest Rate Weighted average interest rate of outstanding investments in money pool. Entity Address, City or Town Entity Address, City or Town Short-Term Borrowings and Long-Term Debt [Table] Short-Term Borrowings and Long-Term Debt [Table] Short-Term Borrowings and Long-Term Debt [Table] Fair value of plan assets measurement [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Other Debt Other Debt [Member] Other Debt Health care cost trend rate assumed for the next year Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year 2025 Lessee, Operating Lease, Liability, to be Paid, Year Five Securities Related to ZENS Financial Instrument [Axis] Type of Adoption [Domain] Accounting Standards Update [Domain] Labor Force Concentration Risk [Member] Labor Force Concentration Risk [Member] Return on equity Public Utilities, Requested Return on Equity, Percentage Short-term lease cost Short-term Lease, Cost Limited partner interest units held Equity Method Investment, Ownership, Shares Equity Method Investment, Ownership, Shares Assets Held for Sale and Discontinued Operations Discontinued Operations, Policy [Policy Text Block] Loss on indexed debt securities Loss (gain) on indexed debt securities Gain (loss) on Indexed Debt Securities This item represents the net total realized and unrealized gain (loss) included in earnings for the period related to indexed debt securities. Number of States in which the Entity Performs Gas Delivery Services Number of States in which the Entity Performs Gas Delivery Services Number of States in which the Entity Performs Gas Delivery Services Natural Gas and Coal Natural Gas and Coal [Member] Natural Gas and Coal Unrecognized equity return (2) Unrecognized Equity Return Represents the balance of the allowed return on equity that has been deferred and recorded on the balance sheet Accrued Unbilled Revenues, Allowance for Credit Losses, Current Accrued Unbilled Revenues, Allowance for Credit Losses, Current Allowance for credit losses on accrued unbilled revenues Dividend to parent Cash dividends paid to parent Payments of Dividends Valuation allowance Deferred tax assets, valuation allowance Deferred Tax Assets, Valuation Allowance Other assets Increase (Decrease) in Other Noncurrent Assets Money pool investments (borrowings) (1) MoneyPoolInvestments Represents investments in the parent company's money pool. 2023 Finite-Lived Intangible Asset, Expected Amortization, Year Three Total assets held for sale Disposal Group, Including Discontinued Operation, Assets Percentage of property additions Percentage of property additions Percentage of property additions Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Debt capital structure Public Utilities, Requested Debt Capital Structure, Percentage Retail Gas Sales [Member] Retail Gas Sales [Member] Represents revenue from retail gas sales Other Other Liabilities, Current Investment, Name [Domain] Investment, Name [Domain] Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Regulatory Asset [Axis] Regulatory Asset [Axis] Leases [Abstract] Leases [Abstract] Accounts payable for natural gas purchases from Enable Accounts Payable, Related Parties, Current Taxes other than income taxes Taxes, Miscellaneous Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Total current assets Current assets Assets, Current Corporate and Other [Member] Corporate and Other [Member] Earnings Per Share [Abstract] Earnings Per Share [Abstract] Operating loss carryforwards Operating Loss Carryforwards Tax Assets and Liabilities [Table Text Block] Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Long-term Debt: Long-term Debt, Excluding Current Maturities [Abstract] Wholesale Electric Sales [Member] Wholesale Electric Sales [Member] Wholesale Electric Sales [Member] Percentage of work yet to be completed on projects with open surety bonds Percentage of work yet to be completed on projects with open surety bonds Percentage of work yet to be completed by wholly owned subsidiary on projects with open surety bonds. Prior service cost (2) Prior service cost (2) Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Change in Contract Liability [Roll Forward] Change in Contract Liability [Roll Forward] Change in Contract Liability [Roll Forward] Workforce Subject to Collective Bargaining Arrangements Expiring in April 2025 Workforce Subject to Collective Bargaining Arrangements Expiring in April 2025 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in April 2025 Disposal Group Name [Domain] Disposal Group Name [Domain] Accounts receivable/payable–affiliated companies Increase decrease in Accounts receivable payable affiliates The increase (decrease) in net accounts receivables and payables due to/from affiliates. Accounts payable related to capital expenditures Accounts payable related to capital expenditures, discontinued operations Accounts payable related to capital expenditures, discontinued operations Net deferred tax liabilities on sale recognized as deferred income tax benefit by CenterPoint Energy Disposal Group, Including Discontinued Operation, Deferred Tax Liabilities Transition bonds 2.161% to 3.028% due 2020 to 2024 Bonds Transition Due Range 3 [Member] Bonds Transition Due Range 3 [Member] Energy Related Derivative [Member] Energy Related Derivative [Member] 2025 Finite-Lived Intangible Asset, Expected Amortization, Year Five Document Fiscal Period Focus Document Fiscal Period Focus Enable Units [Abstract] Enable common units and Series A Preferred Units Held [Abstract] Enable common units and Series A Preferred Units Held [Abstract] Non-trading derivative assets Disposal Group, Including Discontinued Operation, Non-trading derivative assets, non-current Disposal Group, Including Discontinued Operation, Non-trading derivative assets, non-current Decrease in short-term borrowings, net Proceeds from (Repayments of) Other Debt Less: Undistributed earnings allocated to preferred shareholders (1) Net Income (Loss) Available to Common Stockholders, Diluted Employer contributions Total contributions to the plans during the period Defined Benefit Plan, Plan Assets, Contributions by Employer Environmental Improvement Revenue Bonds, Warrick County, 0.875%, Series 2015 [Member] Environmental Improvement Revenue Bonds, Warrick County, 0.875%, Series 2015 [Member] Environmental Improvement Revenue Bonds, Warrick County, 0.875%, Series 2015 Collective Bargaining Arrangement [Domain] Collective-Bargaining Arrangement [Domain] Debt Instrument, Redemption Price, Percentage Debt Instrument, Redemption Price, Percentage Entity Filer Category Entity Filer Category Houston electric stipulation and settlement agreement [Member] Houston electric stipulation and settlement agreement [Member] Houston electric stipulation and settlement agreement [Member] Common Stock [Member] Common Units [Member] Common Stock [Member] Product and Service [Domain] Product and Service [Domain] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Distributions from unconsolidated affiliates in excess of cumulative earnings Proceeds from Equity Method Investment, Distribution, Return of Capital Defined Contribution Plan, Cost Defined Contribution Plan, Cost 2021 Lessor, Operating Lease, Payment to be Received, Year One International Developed Market Equity [Member] International Developed Market Equity [Member] International Developed Market Equity [Member] Amounts recognized in balance sheets Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract] Net regulatory assets and liabilities Increase (Decrease) in Regulatory Assets and Liabilities Other Nonoperating Income (Expense) [Member] Other, net [Member] Other Nonoperating Income (Expense) [Member] Total other assets AssetsNoncurrentOtherThanPropertyPlantAndEquipment Sum of the carrying amounts as of the balance sheet date of assets that are expected to be realized in cash, sold or consumed after one year or beyond the normal operating cycle, if longer, excluding property, plant and equipment. ZENS annual interest rate Debt instrument interest rate Debt Instrument, Interest Rate, Stated Percentage Dividends accrued Dividends Payable, Current Declaration Date Distribution Made to Limited Partner, Declaration Date Expected timing of satisfaction, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block] Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Table Text Block] Schedule of Related Party Transactions [Table Text Block] Schedule of Related Party Transactions [Table Text Block] Defined Contribution Plan, Maximum Limit Of Account Balance In Company Stock, Percentage Defined Contribution Plan, Maximum Limit Of Account Balance In Company Stock, Percentage Represents the maximum percentage allowed of total account balance invested in company stock. Earnings Per Share, Diluted [Abstract] Earnings Per Share, Diluted [Abstract] Total distributions received from Enable Total distributions received from Enable Represents the total amount of distributions received related to both equity method investments and cost method investments from Enable. Total Nonoperating Income (Expense) Lease Disclosure [Line Items] Lease Disclosure [Line Items] [Line Items] for Lease Disclosure [Table] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Distributions Declared, Per Unit Distribution Made to Limited Partner, Distributions Declared, Per Unit Subsequent Events [Abstract] Subsequent Events [Abstract] Gross Amounts Recognized Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement Subsegments Consolidation Items [Domain] Subsegments Consolidation Items [Domain] Adoption of ASU 2018-02 Effect Of Adoption Of New Accounting Standard Effect Of Adoption Of New Accounting Standard Indexed Debt Securities (ZENS) and Securities Related to ZENS (CenterPoint Energy) [Text Block] Indexed Debt Securities [Text Block] This item represents the entire disclosure related to Indexed Debt Securities (ZENS) and Time Warner Securities. State Deferred State and Local Income Tax Expense (Benefit) CenterPoint Energy’s interest Equity Method Investment, Gross Equity In Earnings (Losses) This represents the gross equity in earnings (losses) of equity method investment, excluding any basis difference. 2025 Long-Term Debt, Maturity, Year Five Expected return on plan assets Expected return on plan assets (3) Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets Interest, net of capitalized interest Interest Paid, Excluding Capitalized Interest, Operating Activities Annual maturities of long term debt, capital leases, and sinking fund requirements, excluding ZENS obligations [Abstract] Long-term Debt, Fiscal Year Maturity [Abstract] 3.75% Senior notes [Member] 3.75% Senior notes [Member] 3.75% Senior notes Background [Text Block] Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Rate case expense [Member] Rate case expense [Member] Rate case expense [Member] Natural Gas Distribution [Member] Gas Distribution Equipment [Member] Additional paid-in capital Additional Paid in Capital 2021 Finite-Lived Intangible Asset, Expected Amortization, Year One Total Total revenues Operating revenues Revenues Class of Stock [Axis] Class of Stock [Axis] Income taxes (refunds), net Income Taxes Paid, Net Proceeds from divestitures (Note 4) Cash proceeds from sale Proceeds from Divestiture of Businesses Loss on classification to held for sale, net (2) Gain (Loss) on Sale of Assets and Asset Impairment Charges Utility pipeline construction company [Member] Utility pipeline construction company [Member] Utility pipeline construction company [Member] Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Other comprehensive loss from unconsolidated affiliates OCI, Equity Method Investment, before Tax Proceeds from Issuance of Preferred Stock and Preference Stock Proceeds from the issuance of Series A Preferred Stock, net Proceeds from Issuance of Preferred Stock and Preference Stock Diluted Earnings (Loss) Per Common Share Earnings Per Share, Diluted Reclassification of net deferred losses from cash flow hedges Other Comprehensive Income (Loss), Cash Flow Hedge Gain (Loss) Reclassification To Regulatory Asset After Tax Reclassification of net deferred loss from cash flow hedges net of tax to regulatory assets or regulatory liabilities Fair Value Of Disposal Group Fair Value Of Disposal Group Fair Value Of Disposal Group Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Operation and maintenance Disposal Group, Including Discontinued Operation, Operation and Maintenance Expense The amount of operating expenses for the period that are associated with the discontinued operation's normal revenue producing operation; including selling, general, and administrative expenses, costs incurred for routine plant repairs and maintenance, and operations. Gain (loss) on marketable securities Gain (loss) on ZENS-Related Securities Marketable Securities, Gain (Loss) Depreciation Depreciation Entity Address, Address Line One Entity Address, Address Line One Entity Emerging Growth Company Entity Emerging Growth Company Workforce Subject to Collective Bargaining Arrangements Expiring in May 2021 Workforce Subject to Collective Bargaining Arrangements Expiring in May 2021 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in May 2021 Operating Revenue Business Acquisition, Pro Forma Revenue Deferred income taxes Total deferred expense (benefit) Deferred Income Tax Expense (Benefit) Depositary shares, each representing a 1/20th interest in a share of 7.00% Series B Mandatory Convertible Preferred Stock, $0.01 par value Depositary Shares [Member] Depositary Shares [Member] Related Party Transaction, Other Revenues from Transactions with Related Party Related Party Transaction, Other Revenues from Transactions with Related Party Derivative Liabilities Fair Value Derivative Liability, Fair Value, Gross Liability Target Annual Yield On Reference Shares Target Annual Yield On Reference Shares The target annual yield from interest and cash dividends on reference shares, before any adjustment to increase or decrease principal amount of subordinated note is made. COVID-19 ERP Regulatory Liability COVID-19 ERP Regulatory Liability COVID-19 ERP Regulatory Liability Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Maximum [Member] Maximum [Member] Regulatory Assets and Liabilities Public Utilities, Policy [Policy Text Block] Preferred Stock, Shares Authorized Preferred Stock, Shares Authorized SIGECO 2020 First Mortgage Bonds Remarketing, 0.875%, Series 2015 [Member] SIGECO 2020 First Mortgage Bonds Remarketing, 0.875%, Series 2015 [Member] SIGECO 2020 First Mortgage Bonds Remarketing, 0.875%, Series 2015 Dividends declared Dividends, Common Stock, Cash Current tax expense (benefit) of cash taxes payable upon sale Current tax expense of cash taxes payable upon sale Current tax expense of cash taxes payable upon sale Effective tax rate (in hundredths) Effective Income Tax Rate Reconciliation, Percent Fair Value, assets and liabilities measured on recurring basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] 2023 Lessor, Operating Lease, Payment to be Received, Year Three Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Taxes receivable Increase (Decrease) in Income Taxes Receivable Investments [Domain] Investments [Domain] Postretirement Benefits [Member] Other Postretirement Benefits Plan [Member] Other Postretirement Benefits Plan [Member] Trading Symbol Trading Symbol Summary of Accounting Policies [Table] Summary of Accounting Policies [Table] Summary of Accounting Policies [Table] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Regulatory Liability [Axis] Regulatory Liability [Axis] Remaining average contractual life of nonvested shares outstanding (in years) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms Public unitholders [Member] Public unitholders [Member] Public unitholders [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Payment of debt issuance costs Payment of Financing and Stock Issuance Costs Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization, Consolidation and Presentation of Financial Statements [Abstract] Credit facility swing line sublimit Credit facility swing line sublimit Credit facility swing line sublimit. Other property [Member] Other Capitalized Property Plant and Equipment [Member] Incentive distribution right Incentive Distribution Right, Percentage Entity's interest in incentive distribution rights held by the general partner. Entity Shell Company Entity Shell Company Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Fair Value, Measurements, Recurring [Member] Fair Value, Recurring [Member] 120 Days After Conclusion of Review or Appeal [Member] 120 Days After Conclusion of Review or Appeal [Member] 120 Days After Conclusion of Review or Appeal [Member] Other, net Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount Entity Public Float Entity Public Float Regulatory Agency [Domain] Regulatory Agency [Domain] Unamortized Debt Unamortized Debt Issuance Costs [Member] Unamortized Debt Issuance Costs Document Type Document Type Defined Benefit Plan, Contribution by Employer, Qualified Plan Defined Benefit Plan, Contribution by Employer, Qualified Plan Amount of contributions by the employer to qualified pension plan during the period. ICFR Auditor Attestation Flag ICFR Auditor Attestation Flag Other income, net Other Nonoperating Income (Expense) Cost to sell Disposal Group, Including Discontinued Operation, Other Expense Reporting Unit [Axis] Reporting Unit [Axis] Proliance Holdings LLC [Member] Proliance Holdings LLC [Member] Proliance Holdings LLC [Member] Transportation revenue Discontinued Operation, Intra-Entity Amounts, Discontinued Operation after Disposal, Revenue CenterPoint Energy senior notes 2.50% to 4.25% due 2021 to 2049 (3) Senior Notes Senior Notes Due Range 1 [Member] Senior Notes Due Range 1 [Member] Current tax expense (benefit) of cash taxes payable upon sale Current tax expense (benefit) of cash taxes payable upon sale Current tax expense (benefit) recognized as a result of the cash taxes payable upon sale of business Segments [Axis] Segments [Axis] Net deferred gain (loss) from cash flow hedges Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Weighted average grant date fair value, vested and released to participants (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Write-down of natural gas inventory Inventory Write-down Lessee, Leases [Policy Text Block] Lessee, Leases [Policy Text Block] Amounts related to TCJA [Member] Amounts related to TCJA [Member] Amounts related to TCJA [Member] Long-term Purchase Commitment, Category of Item Purchased [Domain] Long-term Purchase Commitment, Category of Item Purchased [Domain] Long-Term Long-Term Long-term Debt, Gross, Noncurrent Amount of long-term debt, noncurrent portion, before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer. Benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Sales price of outstanding equity interests Sales price of outstanding equity interests Sales price of outstanding equity interests Line of Credit [Member] Line of Credit [Member] 2026 and beyond Lessor, Operating Lease, Payment to be Received, after Year Five Other liabilities Increase (Decrease) in Other Noncurrent Liabilities Deferred income taxes, net Deferred Income Tax Liabilities, Net Derivative Instruments [Text Block] Derivative Instruments and Hedging Activities Disclosure [Text Block] Fuel cost recovery Increase (Decrease) in over (under) Energy Recovery Interest and AFUDC debt (1) Interest Costs Capitalized Adjustment Depreciation and Amortization [Abstract] Depreciation, Depletion and Amortization [Abstract] Accounts receivable and unbilled revenues, net Increase (Decrease) in Accounts and Other Receivables Operating Income Operating Income (Loss) Debt issuance costs Payments of Debt Issuance Costs Postemployment Benefits [Abstract] Postemployment Benefits [Abstract] Environmental remediation number of sites with potential remedial responsibility Environmental remediation number of sites with potential remedial responsibility Number of sites identified where the entity may potentially have some remedial responsibility Other long-term debt, net Other Long-term Debt, Noncurrent Cumulative Preferred Stock [Member] Cumulative Preferred Stock [Member] Severance expense related to the Merger Severance Costs Long-lived Assets, Goodwill and Intangibles Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block] Contract with Customer, Asset and Liability [Table Text Block] Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] 2026 and beyond Purchase Obligation, to be Paid, after Year Five Variable Rate [Axis] Variable Rate [Axis] Indexed debt securities derivative Derivative Component of ZENS Derivative Component of ZENS Indexed debt securities derivative Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Commitments and Contingencies Commitments and Contingencies Guarantees Guarantees, Indemnifications and Warranties Policies [Policy Text Block] 2026 and beyond Lessee, Operating Lease, Liability, to be Paid, after Year Five Equity Method Investment, Difference Between Carrying Amount and Underlying Equity [Abstract] Equity Method Investment, Difference Between Carrying Amount and Underlying Equity [Abstract] Cumulative preferred stock, $0.01 par value, 20,000,000 shares authorized Cumulative Preferred Stock Represents the caption on the face of the balance sheet represent total cumulative preferred stock presented in detail within the Shareholder's Equity section. Taxes accrued Taxes Payable, Current Entity Address, State or Province Entity Address, State or Province Vested and released to participants (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Schedule of Net Pension and Post-retirement Benefit Costs [Table Text Block] Schedule of Defined Benefit Plans Disclosures [Table Text Block] Expected federal income tax expense (benefit) Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Accounts payable Accounts Payable, Current Amount of debt secured by general mortgage bonds Secured debt amount with asset liens Secured Debt System restoration bonds 4.243% due 2022 Bonds System Restoration Due Range 1 [Member] Bonds System Restoration Due Range 1 [Member] Retained earnings (accumulated deficit) Retained Earnings (Accumulated Deficit) Materials and supplies Public Utilities, Inventory Operating ROU assets (1) Operating Lease, Right-of-Use Asset Repayments of Lines of Credit Repayments of Lines of Credit Amortization of securitized regulatory assets Amortization of Regulatory Asset Loss on early extinguishment of debt Gain (Loss) on Extinguishment of Debt Property, plant, and equipment Deferred Tax Liabilities, Property, Plant and Equipment Disclosure of Stock-Based Incentive Compensation Plans and Employee Benefit Plans [Abstract] Disclosure of Stock-Based Incentive Compensation Plans and Employee Benefit Plans [Abstract] Disclosure of Stock-Based Incentive Compensation Plans and Employee Benefit Plans [Abstract] Electric Delivery [Member] Electric Delivery [Member] Represents revenues from electric transmission and distribution sales Period [Domain] Period [Domain] Period SIGECO's share of cost of Warrick Unit 4 Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service Convertible Debt [Table Text Block] Convertible Debt [Table Text Block] Effective Income Tax Rate Reconciliation, Other Adjustments [Axis] Effective Income Tax Rate Reconciliation, Other Adjustments [Axis] Effective Income Tax Rate Reconciliation, Other Adjustments [Axis] Property, plant and equipment, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Shareholders’ Equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Derivative Liability, Notional Amount Derivative Liability, Notional Amount Asset Retirement Obligation [Table Text Block] Schedule of Change in Asset Retirement Obligation [Table Text Block] Major Customers [Axis] Customer [Axis] Gain (loss) on derivative instruments not designated as hedging instruments Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Income Taxes Income Tax, Policy [Policy Text Block] Hedging Designation [Domain] Hedging Designation [Domain] Total lease cost Lease, Cost Fair value of collateral already posted Collateral Already Posted, Aggregate Fair Value Other, net Payments for (Proceeds from) Other Investing Activities Natural gas and coal inventory Energy Related Inventory, Natural Gas in Storage CenterPoint Energy Houston Electric, LLC Houston Electric [Member] Houston Electric [Member] Houston Electric [Member] Current Liabilities [Member] Current Liabilities [Member] Line item in the statement of financial position in which the fair value amounts of the derivative instruments are included. Capitalization of Interest and AFUDC Allowance for Funds Used During Construction, Policy [Policy Text Block] Beginning balance Ending balance Asset Retirement Obligation Asset Retirement Obligation Warranty obligations outstanding face amount Warranty obligations outstanding face amount Warranty obligations outstanding face amount Performance guarantee obligations outstanding face amount Performance guarantee obligations outstanding face amount Face amount of individual surety bonds the wholly-owned subsidiary has outstanding Revenue from contracts Revenue from Contract with Customer, Excluding Assessed Tax Share Price Share Price Regulatory Liability [Domain] Regulatory Liability [Domain] Business Acquisition [Axis] Business Acquisition [Axis] Settlement cost (2) (3) Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] 6.625% Senior Notes due 2037 6.625% Senior Notes Due 2037 [Member] 6.625% Senior Notes Due 2037 [Member] Equity Method Investments, Fair Value Disclosure Equity Method Investments, Fair Value Disclosure Common Units [Member] Common Units [Member] Common Units [Member] Debt Component Of ZENS [Member] Debt Component Of ZENS [Member] Represents the bifurcated fixed rate debt component of the ZENS obligation Fixed Income Funds [Member] Fixed Income Funds [Member] Numerator: Earnings Per Share, Basic and Diluted [Abstract] Regulatory liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities Interest accrued Interest Payable, Current Entity Voluntary Filers Entity Voluntary Filers Opening balance as of December 31, 2019 Closing balance as of December 31, 2020 Accounts Receivable for Contracts with Customers Accounts Receivable for Contracts with Customers Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Public Utilities, General Disclosures [Line Items] Public Utilities, General Disclosures [Line Items] Quarterly increase of fee received for retained CES guarantee exposure Quarterly increase of fee received for retained CES guarantee exposure Quarterly increase of fee received for retained CES guarantee exposure Credit Facility [Axis] Credit Facility [Axis] Preferred Stock, Shares Issued Preferred Stock, Shares Issued Number of shares referenced in exchangeable subordinated note Number Of Shares Referenced In Exchangeable Subordinated Note Number of shares attributable to each note and referenced in determining the fair value of the cash to be exchange at behest of note holder. Total lease payments to be received Lessor, Operating Lease, Payments to be Received Non-trading derivative liabilities Derivative Liability, Noncurrent Accumulated Other Comprehensive Income (Loss) [Roll Forward] Accumulated Other Comprehensive Income (Loss) [Roll Forward] Accumulated Other Comprehensive Income (Loss) [Roll Forward] Operating Lease Liabilities, Payments Due [Abstract] Lessee, Operating Lease, Liability, Payment, Due [Abstract] SIGECO [Member] SIGECO [Member] SIGECO [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Gas Transportation and Processing [Member] Gas Transportation and Processing [Member] Represents revenues from gas transportation and processing Public Utilities General Disclosures [Table Text Block] Public Utilities General Disclosures [Table Text Block] Benefit obligations related to split-dollar life insurance arrangements Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent Split Dollar Life Insurance This represents the noncurrent liability related to split-dollar life insurance arrangements within other non-qualified plans. Total leased assets Lease Right-Of-Use Asset Total Leased Right-Of-Use-Assets Preferred stock threshold consecutive calendar days Preferred Stock, Convertible, Threshold Consecutive Calendar Days Threshold period of consecutive calendar days for fundamental change conversion. AT&T Common [Member] AT&T Common [Member] Common stock of AT&T Inc. Postemployment benefit obligations Postemployment Benefits Liability, Noncurrent Proceeds from issuance of Common Stock, net Proceeds from issuance of common stock Proceeds from Issuance of Common Stock Operating Lease, Lease Income [Table Text Block] Operating Lease, Lease Income [Table Text Block] Property, Plant and Equipment, Net, by Type [Abstract] Property, Plant and Equipment, Net, by Type [Abstract] Basic and Diluted Earnings Per Share [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Current Long-term Debt, Gross, Current Amount of long-term debt scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. CERC Senior notes 4.50% due 2021 [Member] CERC Senior notes 4.50% due 2021 [Member] CERC Senior notes 4.50% due 2021 Asset retirement obligations Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Asset Retirement Obligations Non-utility cost of revenues Disposal Group, Including Discontinued Operation, Costs of Goods Sold Long-term Line of Credit Long-term Line of Credit Accounts and notes receivable (payable) - affiliate companies [Member] Accounts and notes receivable (payable) - affiliate companies [Member] Accounts and notes receivable (payable) - affiliate companies [Member] Repayments of Debt Repayments of Debt Total other liabilities Liabilities, Other than Long-term Debt, Noncurrent Equity Method Investments [Table Text Block] Equity Method Investments [Table Text Block] Funded status of plan Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Total grant date fair values of performance and stock awards which vested during the period Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested In Period Total Grant Date Fair Value The total fair values as of grant dates pertaining to share-based award plans other than stock option plans for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares, other instruments, or cash in accordance with the terms of the arrangement. Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Entity Central Index Key Entity Central Index Key Related Party [Domain] Related Party [Domain] Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Dividends, Distributions, Change [Axis] Dividends, Distributions, Change [Axis] Dividends, Distributions, Change [Axis] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Derivative Instrument [Axis] Derivative, by Nature [Axis] Derivative Instrument [Axis] Non-trading derivative liabilities Disposal Group, Discontinued Operation, Non-trading derivative liabilities Disposal Group, Discontinued Operation, Non-trading derivative liabilities Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Other Noncurrent Liabilities [Member] Other Noncurrent Liabilities [Member] Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table Text Block] Contract Balances [Table] Contract Balances [Table] Contract Balances [Table] Total liabilities held for sale Disposal Group, Including Discontinued Operation, Liabilities Senior Notes [Member] Senior Notes [Member] Supplemental Disclosure of Cash Flow Information [Text Block] Cash Flow, Supplemental Disclosures [Text Block] Net liability, end of year Liability, Defined Benefit Plan Utility natural gas, fuel and purchased power Utilities Operating Expense, Gas and Petroleum Purchased Purchase Accounting Business Combinations and Other Purchase of Business Transactions, Policy [Policy Text Block] Taxes receivable Income Taxes Receivable, Current Undistributed earnings from equity method investments included in retained earnings Retained Earnings, Undistributed Earnings from Equity Method Investees Energy savings commitments not guaranteed Energy savings commitments not guaranteed Energy savings commitments not guaranteed Assets and Liabilities, Lessee [Abstract] Assets and Liabilities, Lessee [Abstract] Reporting Segment [Domain] Segments [Domain] Deferred Tax Assets, Derivative Instruments Deferred Tax Assets, Derivative Instruments ZENS-Related Securities [Member] TW Securities [Member] Represents collectively TW Common, TWC Common, AOL Common and Time Common securities related to ZENS. Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Line of Credit Facility [Abstract] Line of Credit Facility [Abstract] Conversion of Stock, Amount Converted Conversion of Stock, Amount Converted Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Attributable to Parent Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Attributable to Parent Net Income (1) Business Acquisition, Pro Forma Net Income (Loss) 2024 Long-Term Debt, Maturity, Year Four Schedule of Revolving Credit Facilities and Utilization of Such Facilities [Table Text Block] Schedule of Line of Credit Facilities [Table Text Block] Income Statement Location [Axis] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs, by Report Line [Axis] Income Statement Location [Axis] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding International Equity [Member] International Equity [Member] International Equity [Member] Federal Current Federal Tax Expense (Benefit) Stockholders' Equity Note [Abstract] Stockholders' Equity Note [Abstract] Amortization of intangible assets in Non-utility cost of revenues Amortization of Intangible Assets Investments [Member] Investments [Member] Distribution per share of Series A preferred units Distribution per share of Series A preferred units Per share or per unit amount of distributions received from Enable Series A preferred units cost method investment. Unconsolidated Affiliate (CenterPoint Energy and CERC) [Text Block] Equity Method Investments and Joint Ventures Disclosure [Text Block] Reportable Segments [Text Block] Segment Reporting Disclosure [Text Block] ZENS-Related Securities Tw Securities [ Abstract] Issuances of stock Stock Issued During Period, Value, New Issues Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Statement, Scenario [Axis] Scenario [Axis] Payment Date Distribution Made to Limited Partner, Distribution Date SIGECO first mortgage bonds 0.875% to 6.72% due 2022 to 2055 SIGECO first mortgage bonds 0.875% to 6.72% due 2022 to 2055 [Member] SIGECO first mortgage bonds 0.875% to 6.72% due 2022 to 2055 Schedule of Environmental Loss Contingencies by Site [Table Text Block] Schedule of Environmental Loss Contingencies by Site [Table Text Block] Non-trading derivative liabilities Derivative Liability, Current Changes in plan assets and benefit obligations recognized in other comprehensive income Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Title of 12(b) Security Title of 12(b) Security Disposal Group Classification [Axis] Disposal Group Classification [Axis] Investment in marketable securities and indexed debt Deferred Tax Liabilities, Investments Income (loss) from Discontinued Operations before income taxes Income (loss) before income taxes Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax Net Balance Finite-Lived Intangible Assets, Net Transition bonds 5.234% due 2020 Bonds Transition Due Range 1 Member [Member] Bonds Transition Due Range 1 Member [Member] The cash exchange amount from referenced shares per $1,000 face amount of individual notes Subordinated Note Cash Exchange Amount Per Each $1,000 Of Original Note The amount of cash each $1,000 original principal amount of ZENS can be exchanged for a the behest of the note holder. Affiliates of Vistra Energy Corp. [Member] Affiliates of Vistra Energy Corp. [Member] Affiliates of Vistra Energy Corp. [Member] 2022 Lessor, Operating Lease, Payment to be Received, Year Two Enable Distributions [Abstract] Enable Distributions [Abstract] Enable Distributions [Abstract] Reconciliation of Unrecognized Tax Benefits, excluding interest and penalties: Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Depreciation and amortization Total Depreciation and Amortization Depreciation, Depletion and Amortization Income Tax Expense [Table Text Block] Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Preferred stock liquidation preference (per share) Preferred Stock, Liquidation Preference Per Share Discontinued Operations [Member] Discontinued Operations [Member] Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Accounting Standards Update and Change in Accounting Principle [Table Text Block] Environmental Remediation Site [Axis] Environmental Remediation Site [Axis] Product and Service [Axis] Product and Service [Axis] Hurricane Laura Hurricane Laura [Member] Restoration costs related to Hurricane Laura Investment Type [Axis] Investment Type [Axis] Operation And Maintenance Expense [Member] Operation And Maintenance Expense Member Amount of share-based compensation cost reported in the period, allocated to operations and maintenance expense. Operations and maintenance expense are the costs associated with normal operations, including general and administrative expenses, and routine plant maintenance and repairs. Weighted average period of recognition (in years) Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition Supplemental Cash Flow Elements [Abstract] Supplemental Cash Flow Elements [Abstract] 2022 Long-Term Debt, Maturity, Year Two Asset Retirement Obligation Costs [Member] Asset Retirement Obligation Costs [Member] New York Stock Exchange New York Stock Exchange [Member] New York Stock Exchange [Member] Sinking fund requirements to be satisfied in 2018 Sinking Fund Requirements Amount to be paid in following year into the sinking fund. Such amount may be satisfied by certification of property additions. Contract with Customer, Liability, Revenue Recognized Contract with Customer, Liability, Revenue Recognized Income (Loss) Available to Common Shareholders Net income (loss) attributable to Enable common units Income (loss) available to common shareholders from continuing operations - basic and diluted Net Income (Loss) Available to Common Stockholders, Basic Other Deferred Tax Liabilities Noncurrent Other The cumulative amount of the estimated future tax effects attributable to other temporary differences not otherwise specified in this taxonomy that are expected to reverse more than 12 months after the balance sheet date. Fair Value Assets And Liabilities Measured On Recurring Basis [Table] Fair Value, Recurring and Nonrecurring [Table] Accounts payable Increase (Decrease) in Accounts Payable Employees Subject To Collective Bargaining Agreements [Member] Employees Subject To Collective Bargaining Agreements [Member] Represents the employees subject to collective bargaining agreements. Basic earnings (loss) per common share - discontinued operations Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share Stock Awards [Member] Stock Awards Member Stock awards within the entity's long-term stock incentive plan. Depreciation and amortization expense [Member] Depreciation and amortization expense [Member] Depreciation and amortization expense [Member] Lessee Operating Lease Not Yet Commenced Lessee Operating Lease Not Yet Commenced Lessee, Undiscounted minimum lease payments for operating leases signed but not yet commenced Debt Instrument [Axis] Debt Instrument [Axis] Benefit Obligation [Member] Benefit Obligation [Member] Represents the benefit obligation on the balance sheet. CenterPoint Energy [Member] CenterPoint Energy [Member] Another company which is controlled, directly or indirectly, by its parent. The usual condition for control is ownership of a majority (over 50%) of the outstanding voting stock. The power to control may also exist with a lesser percentage of ownership, for example, by contract, lease, agreement with other stockholders or by court decree. Change in Contract Asset [Roll Forward] Change in Contract Asset [Roll Forward] Change in Contract Asset [Roll Forward] Schedule of Business Acquisitions, by Acquisition [Table Text Block] Schedule of Business Acquisitions, by Acquisition [Table Text Block] Partner Type [Axis] Partner Type [Axis] Second Quarter 2020 [Member] Second Quarter 2020 [Member] Second Quarter 2020 [Member] Operating Segments [Member] Operating Segments [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Reclassified to earnings Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Unamortized loss on reacquired debt (3) Unamortized Loss Reacquired Debt, Noncurrent Derivative Liability Derivative Liability Opening balance as of December 31, 2019 Closing balance as of December 31, 2020 Unbilled Contracts Receivable Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Revenue from Contract with Customer [Abstract] Revenue from Contract with Customer [Abstract] Depreciation and amortization on assets held for sale Depreciation and Amortization, Discontinued Operations Regulatory assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets Operating Activities [Domain] Operating Activities [Domain] Entity Information [Line Items] Entity Information [Line Items] Margin deposits, net Increase (Decrease) in Margin Deposits Outstanding State income tax expense, net of federal income tax Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Utility revenues Regulated Operating Revenue Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract] Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract] Projected benefit obligation Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation Subsequent Event [Member] Subsequent Event [Member] Total Disposal Group, Including Discontinued Operation, Operating Expense Electric Distribution [Member] Electric Distribution [Member] Domestic Tax Authority Domestic Tax Authority [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Current portion of VIE Securitization Bonds long-term debt Transition And System Restoration Bonds Long Term Debt Current Long-term transition and system restoration bonds are securitization bonds issued to recover qualified stranded costs and qualified storm recovery costs. This represents the current portion. Proceeds from the issuance of Series B Preferred Stock, net Proceeds from Issuance of Convertible Preferred Stock Revenues Revenue [Policy Text Block] Affiliates of NRG Energy, Inc. [Member] Affiliates of NRG Energy, Inc. [Member] Affiliates of NRG Energy, Inc. [Member] Fair value [Member] Estimate of Fair Value Measurement [Member] Conversion of Stock, Amount Issued Conversion of Stock, Amount Issued Non-current operating lease liability (3) Operating Lease, Liability, Noncurrent 2024 Finite-Lived Intangible Asset, Expected Amortization, Year Four PreferredStockSharesToBeConvertedToCommon PreferredStockSharesToBeConvertedToCommon PreferredStockSharesToBeConvertedToCommon Workforce Subject to Collective Bargaining Arrangements Expiring June 2022, Additional Workforce Subject to Collective Bargaining Arrangements Expiring June 2022, Additional [Member] Workforce Subject to Collective Bargaining Arrangements Expiring June 2022, Additional Technology Hardware and Software Technology Hardware and Software [Member] Technology Hardware and Software Depreciation and Amortization Expense Depreciation, Depletion, and Amortization [Policy Text Block] Other Tax Carryforward [Line Items] Tax Credit Carryforward [Line Items] Current Assets: Assets, Current [Abstract] Series B [Member] Series B [Member] Other amortization Amortization Cash Flows from Investing Activities: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Investments, including money market funds (1) Investments, Fair Value Disclosure Depositary Share [Member] Depositary Share [Member] Each depositary Share represents 1/20th share of Series B Preferred Stock. Energy Services Disposal Group [Member] Energy Services Disposal Group [Member] Energy Services Disposal Group Financing Commitments Financing Commitments Financing Commitments Comprehensive income (loss) available to common shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Preferred Stock, Convertible, Conversion Price Preferred Stock, Convertible, Conversion Price The price per share of the conversion feature embedded in the preferred stock. Preferred Stock, $0.01 par value Preferred stock par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Not Designated as Hedging Instrument, Economic Hedge [Member] Not Designated as Hedging Instrument, Economic Hedge [Member] Reconciliation of Expected Federal Income Tax Expense to Actual [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] 2021 Long-Term Debt, Maturity, Year One Indexed debt, net Debt Component of ZENS Debt Component of ZENS Indexed Debt Current Rate of increase in compensation levels Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Electric Generation Equipment [Member] Electric Generation Equipment [Member] Natural Gas [Member] Natural Gas [Member] Segment information for the Natural Gas segment which consists of intrastate natural gas sales to, and natural gas transportation and distribution for, residential, commercial, industrial and institutional customers. City Area Code City Area Code Legal Entity [Axis] Legal entity [Axis] Legal Entity [Axis] Income Tax Authority [Axis] Income Tax Authority [Axis] Document Period End Date Document Period End Date Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Pension benefits that have accumulated benefit obligations in excess of plan assets Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract] Supplemental Balance Sheet Information Related To Leases [Table Text Block] Supplemental Balance Sheet Information Related To Leases [Table Text Block] Supplemental Balance Sheet Information Related To Leases [Table Text Block] Preferred stock redemption price (per share) Preferred Stock, Redemption Price Per Share Dividends Declared [Table Text Block] Dividends Declared [Table Text Block] Disaggregation of Revenue [Table Text Block] Disaggregation of Revenue [Table Text Block] Cash received as collateral from securities [Member] Cash Received As Collateral Member The fair value of cash collateral received against securities loaned to borrowers. Preferred Stock Dividends Stockholders' Equity Note, Redeemable Preferred Stock, Issue, Policy [Policy Text Block] Minnesota and Indiana Gas Service Territories [Member] Minnesota and Indiana Gas Service Territory [Member] Minnesota and Indiana Gas Service Territory [Member] Remeasurement of pension and other postretirement plans Deferred loss from interest rate derivatives (1) Other Comprehensive Income (Loss), before Reclassifications, before Tax Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Share-based Payment Arrangement, Cost by Plan [Table Text Block] Capital expenditures Payments to Acquire Productive Assets Nature of Expense [Axis] Nature of Expense [Axis] Other comprehensive loss from unconsolidated affiliates, tax OCI, Equity Method Investment, Tax Other, net Proceeds from (Payments for) Other Financing Activities Stub period [Member] Stub period [Member] Stub period [Member] Period [Axis] Period [Axis] Period of the transaction occurred [Axis] Preferred Stock, Redemption, Period [Domain] Preferred Stock, Redemption, Period [Domain] [Domain] for Preferred Stock, Redemption, Period [Axis] Cover [Abstract] Cover [Abstract] Regulatory Asset [Domain] Regulatory Asset [Domain] Loss from reclassification to held for sale Loss from reclassification to held for sale Loss from reclassification to held for sale Distributions from unconsolidated affiliates Expected cash distribution on Enable Common Units Proceeds from Equity Method Investment, Distribution System restoration costs threshold for increase in permitted debt to EBITDA covenant ratio Restoration Cost Expected Cost The minimum amount of estimated restoration cost in a calendar year in order for a temporary increase in debt to EBITDA covenant Income Statement Impact of Derivative Activity [Abstract] Income Statement Impact of Derivative Activity [Abstract] Income Statement Impact of Derivative Activity [Abstract] Long-term Debt Long-term Debt Hurricane Harvey Hurricane Harvey [Member] Restoration costs related to Hurricane Harvey Increase (Decrease) in Contract with Customer, Liability Increase (Decrease) in Contract with Customer, Liability Pre-tax gain on sale Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax Leases [Text Block] Lessee, Operating Leases [Text Block] First mortgage bonds 9.15% due 2021 Bonds First Mortgage Due2021 Member A loan secured by real property that has a first (highest) lien on such property in the event of default by the borrower. OGE [Member] OGE [Member] OGE [Member] Participant contributions Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant Service cost (1) Defined Benefit Plan, Service Cost Interest Income on Securitization Bonds Interest Income on Transition and System Restoration Bonds Interest Income on Transition and System Restoration Bonds Money Pool Borrowings MoneyPoolBorrowings Represents borrowings from the parent company's money pool. Concentration Risk by Benchmark [Axis] Concentration Risk Benchmark [Axis] Customer Relationships [Member] Customer Relationships [Member] Non-utility cost of revenues, including natural gas Cost of Goods and Services Sold Lease, Cost [Abstract] Lease, Cost [Abstract] Capital distribution to parent associated with Internal Spin Capital distribution to parent associated with Internal Spin Capital distribution to parent associated with Internal Spin Income (Loss) from Discontinued Operations Net income (loss) from Discontinued Operations Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Total Costs and Expenses Equity Components [Axis] Equity Components [Axis] Contingent principal amount of indexed debt securities issued by CenterPoint Energy in September 1999 and outstanding and exchangeable Debt Instrument Contingent Principal Amount Outstanding Amount of outstanding contingent principal under the zero premium exchangeable subordinated notes contract contingent principal clause. 2 % interest paid Interest Paid Debt Component Indexed Debt Securities The amount of stated interest paid during the current period for interest owed on debt component of ZENS. Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Minimum [Member] Minimum [Member] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Total assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Equity Method Investment, Other than Temporary Impairment Impairment of CenterPoint Energy’s equity method investment in Enable Equity Method Investment, Other than Temporary Impairment Long-term debt Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract] Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract] Non-utility revenues Unregulated Operating Revenue Accumulated benefit obligation Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] Remaining weighted average period for which no return on investment during recovery period is provided Remaining Recovery Period of Regulatory Assets for which No Return on Investment During Recovery Period is Provided Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments and Joint Ventures [Abstract] Amortization of net loss (2) Defined Benefit Plan, Amortization of Gain (Loss) Relief Program Incremental Costs (COVID-19) Relief Program Incremental Costs (COVID-19) [Member] Relief Program Incremental Costs (COVID-19) Entity Interactive Data Current Entity Interactive Data Current Net periodic cost (credit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Schedule of Allocation of Plan Assets [Table Text Block] Schedule of Allocation of Plan Assets [Table Text Block] Revenues: Revenues [Abstract] Workforce Subject to Collective Bargaining Arrangements [Member] Workforce Subject to Collective Bargaining Arrangements [Member] Equity (CenterPoint Energy) [Text Block] Stockholders' Equity Note Disclosure [Text Block] SharesIssuedUponConversion SharesIssuedUponConversion SharesIssuedUponConversion Preferred units held Preferred Units Held Represents the number of Series A Preferred Units held as of the balance sheet date. Distributions received from Enable cost method investment Expected cash distribution on Enable's Series A Preferred Units Cost Method Investment, Dividends Or Distributions This item represents disclosure of the amount of dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporation; these investments are accounted for under the cost method of accounting. This element excludes distributions that constitute a return of investment, which are classified as investing activities. Other Disposal Group, Including Discontinued Operation, Other Assets, Current 2023 Purchase Obligation, to be Paid, Year Three Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Total deferred tax liabilities Deferred Tax Liabilities, Gross Pension benefit payments 2020 Defined Benefit Plan, Expected Future Benefit Payment, Year One Receivable from sale of disposal group Receivable from sale of disposal group Receivable from sale of disposal group Proceeds from sale of assets Proceeds from Sale of Property, Plant, and Equipment Entity Listings, Exchange [Axis] Entity Listings, Exchange [Axis] Preferred Stock, Redemption, Period [Axis] Preferred Stock, Redemption, Period [Axis] Preferred Stock, Redemption, Period [Axis] Enable Partnership Interest [Abstract] Limited Partner Interest in Enable [Abstract] Limited Partner Interest in Enable [Abstract] Employee Service Share-based Compensation, Aggregate Disclosures [Abstract] Share-based Payment Arrangement, Additional Disclosure [Abstract] Bonds Pollution Control Due Range 1 [Member] Bonds Pollution Control Due Range 1 [Member] Bonds Pollution Control Due Range 1 [Member] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Exercise Price Range [Axis] Exercise Price Range [Axis] Denominator: Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Consolidation Items [Axis] Consolidation Items [Axis] Net loss (gain) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Accounts receivable Accounts Receivable, after Allowance for Credit Loss, Current Goodwill impairment Goodwill, Impairment Loss Goodwill, Impairment Loss Beginning Balance Ending Balance Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax Total lease payments Lessee, Operating Lease, Liability, to be Paid Regulatory Accounting [Text Block] Public Utilities Disclosure [Text Block] Transaction with Enable [Abstract] Transaction with Enable [Abstract] Transaction with Enable [Abstract] Other Adjustments to Additional Paid in Capital, Other Total lease income Operating Lease, Lease Income Operating Leases, Lease Income [Abstract] Operating Lease, Lease Income [Abstract] Beneficial Conversion Feature Non-cash transaction beneficial conversion feature Non-cash transaction beneficial conversion feature Plan obligations assumed in Merger Defined Benefit Plan, Benefit Obligation, Business Combination Operating lease income Operating Lease, Lease Income, Lease Payments Payment Date Dividends Payable, Date to be Paid Declaration Date Dividends Payable, Date Declared Accounts and notes receivable, net Accounts and Financing Receivable, after Allowance for Credit Loss Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block] Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block] Gain (loss) reclassified from accumulated OCI into income Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Document Transition Report Document Transition Report Bond Companies [Member] Bond Companies [Member] Bond Companies [Member] Deferred income tax expense (benefit): Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Actual tax benefit realized for tax deductions Share-based Payment Arrangement, Exercise of Option, Tax Benefit Other liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Derivative Assets Fair Value Derivative Asset, Fair Value, Gross Asset Interest income (expense), net (1) Interest Income (Expense) Net, Related Party Net interest income (expense) related to affiliate investments or borrowings SIGECO's share of accumulated depreciation of Warrick Unit 4 Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation Other Income (Expense): Nonoperating Income (Expense) [Abstract] Additional Debt Issueable Additional Debt Issueable Additional Debt Issueable Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Excess of Replacement or Current Costs over Stated LIFO Value Excess of Replacement or Current Costs over Stated LIFO Value Schedule of Regulatory Assets and Liabilities [Table] Schedule Of Regulatory Assets And Liabilities [Table] A table of assets and liabilities that are created when regulatory agencies permit public utilities to defer certain costs and the recognition of certain revenues that are included in rate-setting to the balance sheet. Liabilities Liabilities, Fair Value Disclosure [Abstract] Current income tax expense (benefit): Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Accounts Receivable, Related Parties Accounts Receivable, Related Parties Components of net periodic costs [Abstract] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Number of depositary shares eligible for conversion (in shares) Conversion of Stock, Shares Converted Other Benefit Plans [Table Text Block] Other Benefit Plans [Table Text Block] Other Benefit Plans [Table Text Block] Accounting Standards Update 2016-13 [Member] Accounting Standards Update 2016-13 [Member] Accumulated other comprehensive loss Equity Method Investment Summarized Financial Information Accumulated Other Comprehensive Income Loss EquityMethodInvestmentSummarizedFinancialInformationAccumulatedOtherComprehensiveIncomeLoss Subsequent Event [Line Items] Subsequent Event [Line Items] Enable GP, LLC [Member] Enable GP, LLC [Member] Enable GP, LLC [Member] Other Liabilities Other Liabilities [Member] Credit Facility [Domain] Credit Facility [Domain] Unamortized Discount (Premium), Net Debt Instrument, Unamortized Discount (Premium), Net Earnings Per Share, Basic Earnings Per Share, Basic Earnings Per Share, Basic Entity File Number Entity File Number Curtailment gain (2) (4) Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment Other Current Liabilities [Member] Other Current Liabilities [Member] Benefit obligations Other liabilities-benefit obligations Liability, Defined Benefit Plan, Noncurrent Weighted-average remaining lease term (in years) - operating leases Operating Lease, Weighted Average Remaining Lease Term Rate of increase in compensation levels Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Workforce Subject to Collective Bargaining Arrangements Expiring in December 2025 Workforce Subject to Collective Bargaining Arrangements Expiring in December 2025 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in December 2025 Estimated Fair Value Finite-lived Intangible Assets Acquired Schedule of Regulatory Assets and Liabilities [Table Text Block] Schedule of Regulatory Assets and Liabilities [Table Text Block] Schedule of Regulatory Assets and Liabilities [Table Text Block] Purchase Obligations Long-term Purchase Commitment [Line Items] Cash Flows from Operating Activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] 2024 Lessor, Operating Lease, Payment to be Received, Year Four Disposal Groups, Including Discontinued Operations [Table Text Block] Disposal Groups, Including Discontinued Operations [Table Text Block] Common Stock dividends declared (see Note 13) Dividends, Common Stock Charter Common [Member] Charter Common [Member] Charter Common [Member] Unrecognized prior service cost Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax Goodwill Disposal Group, Including Discontinued Operation, Goodwill, Noncurrent LTIP compensation expense Share-based Payment Arrangement, Expense Balance Sheet Location [Axis] Balance Sheet Location [Axis] Contribution From Parent Contribution From Parent Contribution From Parent Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Disclosure [Abstract] Disposal Group Name [Axis] Disposal Group Name [Axis] Indiana Electric Integrated [Member] Indiana Electric Integrated [Member] Segment information for the Indiana Electric Integrated reportable segment which consists of electric transmission and distribution services primarily to southwestern Indiana and includes power generation and wholesale power operations MISO Transactions MISO Transactions [Policy Text Block] With the IURC's approval, the Company is a member of the MISO, a FERC approved regional transmission organization. The MISO serves the electrical transmission needs of much of the Midwest and maintains operational control over the Company's electric transmission facilities as well as that of other Midwest utilities. MISO-related purchase and sale transactions are accounted for on a net hourly position. Net Purchases are recorded in Cost of Fuel and Purchased Power, and net sales are recorded in Electric Utility Revenues. Any revenues received from MISO for transactions not specifically assigned to a unit of power, such as use of the transmission system or other administrative amounts, are reflected in Electric Utility revenues. Any expenses incurred within the MISO market by the Company that are not specifically identified with a unit of power purchased, such as socialized administrative costs, are treated as Other Operating expense. Document Annual Report Document Annual Report Commercial paper (4) Commercial Paper [Member] Income tax benefit recognized related to LTIPs Share-based Payment Arrangement, Expense, Tax Benefit Category of Item Purchased [Axis] Category of Item Purchased [Axis] IDS Derivative [Member] IDS Derivative [Member] Derivative instrument related to indexed debt securities Natural gas inventory Disposal Group, Including Discontinued Operation, Inventory, Current Accretion of debt component of ZENS Accretion Of Debt Component Indexed Debt Securities The amount of annual balance buildup of the debt portion of indexed debt securities up to the contingent principal amount on debt component of ZENS. Vectren acquisition [Member] Vectren acquisition [Member] Vectren acquisition [Member] Proceeds from Merger - Interest Proceeds from Merger - Interest Cash Received in exchange for its interest in Enable GP Subsequent Event [Table] Subsequent Event [Table] Other Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent Issuances related to benefit and investment plans Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture Summary of Income Tax Contingencies [Table Text Block] Summary of Income Tax Contingencies [Table Text Block] Non-controlling interest Stockholders' Equity Attributable to Noncontrolling Interest Increase (Decrease) in Contract with Customer, Asset Increase (Decrease) in Contract with Customer, Asset Weighted average grant date fair values of awards granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Investment in unconsolidated affiliates Deferred Tax Liabilities, Investment in Noncontrolled Affiliates Derivative, Credit Risk Related Contingent Features [Abstract] Derivative, Credit Risk Related Contingent Features [Abstract] Short-term borrowings Short-term Debt Workforce Subject to Collective Bargaining Arrangements Expiring December 2023 Workforce Subject to Collective Bargaining Arrangements Expiring December 2023 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring December 2023 Public Utility Commission of Texas [Member] Public Utility Commission of Texas [Member] Public Utility Commission of Texas [Member] Customer relationships and trade names [Member] Customer relationships and trade names [Member] Customer relationships and trade names [Member] Balance of investment owned (in shares) Investment Owned, Balance, Shares Securitized regulatory assets Securitized Regulatory Transition Assets, Noncurrent Public Utilities, Regulatory Proceeding [Domain] Public Utilities, Regulatory Proceeding [Domain] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Debt, Capital Ratio Debt, Capital Ratio Debt, Capital Ratio Defined Benefits Plan, Fair Value Of Plan Assets, Excluding Investments Measured at Net Asset Value Defined Benefits Plan, Fair Value Of Plan Assets, Excluding Investments Measured at Net Asset Value Fair value of assets that have been segregated and restricted to provide pension or postretirement benefits, excluding investments measured at net asset value per share or its equivalent. Total regulatory liabilities Regulatory Liabilities Interest Expense [Member] Interest Expense [Member] Amortization of Beneficial Conversion Feature Amortization of Beneficial Conversion Feature Less: Amortization of Beneficial Conversion Feature Amortization of Beneficial Conversion Feature Amortization of Beneficial Conversion feature of Series C Preferred Stock Current liabilities held for sale Total current liabilities held for sale Disposal Group, Including Discontinued Operation, Liabilities, Current 6.95% General Mortgage Bonds due 2033 6.95% General Mortgage Bonds Due 2033 [Member] 6.95% General Mortgage Bonds Due 2033 [Member] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Plan amendment Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment Total Liabilities and Shareholders’ Equity Liabilities and Equity Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Income Taxes [Text Block] Income Tax Disclosure [Text Block] Non-current liabilities Liabilities, Noncurrent Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in July 2022 Workforce Subject to Collective Bargaining Arrangements Expiring in July 2022 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in July 2022 Accounts payable Disposal Group, Including Discontinued Operation, Accounts Payable Operating lease cost Operating Lease, Cost Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Net assets acquired Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Total liabilities assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Hedging Relationship [Axis] Hedging Relationship [Axis] Deferred tax liabilities: Deferred Tax Liabilities, Gross [Abstract] Catastrophic Event [Domain] Catastrophic Event [Domain] Series C Preferred Stock [Member] Series C Preferred Stock [Member] Amount of antidilutive securities excluded from computation of earnings per share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Total current expense (benefit) Current Income Tax Expense (Benefit) CERC Senior notes 1.75% due 2030 [Member] CERC Senior notes 1.75% due 2030 [Member] Issued October 2020, CERC Senior notes 1.75% due 2030 Midstream Investments [Member] Midstream Investments [Member] Midstream Investments [Member] Equity capital structure Public Utilities, Requested Equity Capital Structure, Percentage Increases related to tax positions of prior years Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Unrealized loss (gain) on marketable securities Marketable Securities, Unrealized Gain (Loss), Excluding Other-than-temporary Impairment Loss Equity Component [Domain] Equity Component [Domain] Equity Method Investment, Summarized Financial Information [Abstract] Equity Method Investment, Summarized Financial Information [Abstract] Schedule of Expected Benefit Payments [Table Text Block] Schedule of Expected Benefit Payments [Table Text Block] Property, Plant and Equipment, Net, Total Property, Plant and Equipment, Net Property, Plant and Equipment, Net Schedule of Money Pool Investment and Borrowing [Table Text Block] Schedule of Money Pool Investment and Borrowing [Table Text Block] [Table Text Block] for Tabular disclosure the investments and borrowing within the money pool activities. Entity Tax Identification Number Entity Tax Identification Number Charitable Contribution [Member] Charitable Contribution [Member] Charitable Contribution [Member] Other non-qualified plans benefit obligations deferred compensation Deferred Compensation Liability, Classified, Noncurrent Cumulative Effect on Retained Earnings Cumulative Effect on Retained Earnings Cumulative effect on beginning retained earnings for the adoption of a new accounting standard Interest Rate Contract [Member] Interest Rate Contract [Member] Net Income (Loss) Net Income (Loss) Net income (loss) Net Income (Loss) Attributable to Parent Changes in other assets and liabilities, excluding acquisitions: Increase (Decrease) in Operating Capital [Abstract] Savings Plan [Abstract] Savings Plan Abstract Plan assets assumed in Merger Defined Benefit Plan, Plan Assets, Business Combination Pro Forma [Member] Pro Forma [Member] London Interbank Offered Rate (LIBOR) [Member] London Interbank Offered Rate (LIBOR) [Member] Securities Related to ZENS Debt Securities, Trading, and Equity Securities, FV-NI [Table] Trade Names [Member] Trade Names [Member] Non-trading derivatives, net Increase (Decrease) in Derivative Assets and Liabilities Incremental Uncollectible Receivables, Regulatory Asset Incremental Uncollectible Receivables, Regulatory Asset Incremental Uncollectible Receivables, Regulatory Asset Current Fiscal Year End Date Current Fiscal Year End Date Minnehaha Academy Gas Explosion [Member] Damage from Fire, Explosion or Other Hazard [Member] Expenses: Operating Expenses [Abstract] Enable Equity Summary [Abstract] Enable Equity Summary [Abstract] Enable Equity Summary [Abstract] Revised Dividend or Distribution [Member] Revised Dividend or Distribution [Member] Revised Dividend or Distribution [Member] Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Weighted average recovery period Regulatory Assets, Weighted Average Recovery Period Regulatory Assets, Weighted Average Recovery Period Taxes other than income taxes Disposal Group, Including Discontinued Operation, Taxes Other than Income Taxes Disposal Group, Including Discontinued Operation, Taxes Other than Income Taxes Provision for doubtful accounts [Table Text Block] Provision for doubtful accounts [Table Text Block] Management reviews the outstanding accounts receivable, as well as the bad debt write-offs experienced in the past, and establishes 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. Preferred Stock, Dividend Payment Rate, Variable Preferred Stock, Dividend Payment Rate, Variable Total recognized in comprehensive income Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent Identifiable intangibles Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Series A Preferred Units [Member] Series A Preferred Units [Member] Series A Preferred Units [Member] Series A Preferred Units [Member] Summary of changes in shares outstanding under all long-term incentive plans [Rollforward] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Parent Company [Member] Parent Company [Member] Materials and supplies Disposal group, Including Discontinued Operation, Materials and Supplies Disposal group, Including Discontinued Operation, Materials and Supplies Adjustment to pension and other postretirement plans Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent Long term Debt Excluding ZENS [Member] Long term Debt Excluding ZENS [Member] Represents balances related to long-term debt excluding ZENS Total intrinsic value of awards received by participants Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Vested Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] ROU Asset Obtained In Exchange for Operating Lease Liability, Including Transition Impact of ASC 842 Adoption ROU Asset Obtained In Exchange for Operating Lease Liability, Including Transition Impact of ASC 842 Adoption ROU Asset Obtained In Exchange for Operating Lease Liability, Including Transition Impact of ASC 842 Adoption Stock-Based Incentive Compensation Plans and Employee Benefit Plans [Text Block] Pension And Postretirement Benefits And Share Based Payments Disclosure Text Block Description containing the entire pension and other postretirement benefits and share-based compensation disclosures as a single block of text. Energy Services [Member] Energy Services [Member] Segment information for the Energy Services segment which offers variable and fixed price physical natural gas supplies primarily to commercial and industrial customers and electric and gas utilities. Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property, Plant and Equipment, Type [Domain] Long-Lived Tangible Asset [Domain] Lease Disclosure [Table] Lease Disclosure [Table] Lease Disclosure [Table] Letters of credit swing line sublimit Letters of credit swing line sublimit Letters of credit swing line sublimit General Mortgage Bonds Due 2050 [Member] General Mortgage Bonds Due 2050 [Member] General Mortgage Bonds Due 2050 [Member] Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Construction backlog [Member] Customer Contracts [Member] Dividend to parent Dividends, Cash Preferred stock redemption percentage liquidation value Preferred Stock Redemption Percentage of Liquidation Value The percentage of the liquidation value per share of preferred stock of an entity that has priority over common stock in the distribution of dividends and in the event of liquidation of the entity is redeemed or may be called at. Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Schedule of Defined Benefit Plan Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block] Schedule of Property, Plant and Equipment [Table Text Block] Property, Plant and Equipment [Table Text Block] Preferred Stock, Convertible, Percent Outstanding Shares To Amend Preferred Stock, Convertible, Percent Outstanding Shares To Amend Preferred Stock, Convertible, Percent Outstanding Shares To Amend Total expense recognized in net periodic cost and other comprehensive income Defined Benefit Plan, Amount Recognized in Net Periodic Benefit Cost (Credit) and Other Comprehensive (Income) Loss, before Tax Proceeds from Merger - Preferred Units Proceeds from Merger - Preferred Units Energy Transfer Series G Preferred Units in Exchange for all of its Enable Series A Preferred Units Preferred stock dividend rate Preferred Stock, Dividend Rate, Percentage U.S. treasuries [Member] US Treasury Securities [Member] Issuances of stock Stock issued (in shares) Stock Issued During Period, Shares, New Issues Gross Carrying Amount Finite-Lived Intangible Assets, Gross Unrecognized Tax benefit, impacting ETR if recognized Unrecognized Tax benefit, impacting ETR if recognized Unrecognized Tax benefit, impacting ETR if recognized Finite-Lived Intangible Assets, Net [Abstract] Finite-Lived Intangible Assets, Net [Abstract] Bad debt expense Accounts Receivable, Credit Loss Expense (Reversal) Preferred Stock, Dividends, Per Share, Cash Paid Preferred Stock, Dividends, Per Share, Cash Paid Accumulated Depreciation, and Amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Opening balance as of December 31, 2019 Closing balance as of December 31, 2020 Contract with Customer, Asset, after Allowance for Credit Loss, Current Unrecognized actuarial loss (gain) Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax Amounts recognized in accumulated other comprehensive loss Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract] CenterPoint Energy Resources Corp. CERC Corp [Member] CERC Corp [Member] Another company which is controlled, directly or indirectly, by its parent. The usual condition for control is ownership of a majority (over 50%) of the outstanding voting stock. The power to control may also exist with a lesser percentage of ownership, for example, by contract, lease, agreement with other stockholders or by court decree. Related Party Transactions [Abstract] Related Party Transactions [Abstract] Hedging Relationship [Domain] Hedging Relationship [Domain] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Lessee, Operating Lease, Liability, Maturity [Table Text Block] Lessee, Operating Lease, Liability, Maturity [Table Text Block] Real Estate Funds [Member] Real Estate Funds [Member] Income tax reconciliation [Abstract] Effective Income Tax Rate Reconciliation, Amount [Abstract] State valuation allowance, net of federal income tax Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Workforce Subject to Collective Bargaining Arrangements Expiring in October 2021 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringinOctober2021 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringinOctober2021 [Member] Weighted Average Common Shares Outstanding, Basic Weighted average common shares outstanding - basic Weighted Average Number of Shares Outstanding, Basic Basis spread on LIBOR Debt Instrument, Basis Spread on Variable Rate Capital distribution to parent associated with the sale of CES Other Significant Noncash Transaction, Value of Consideration Given Merger with Vectren [Abstract] Merger with Vectren [Abstract] Merger with Vectren [Abstract] Cash and Cash Equivalents [Member] Cash and Cash Equivalents [Member] Other (1) Other Revenue Excluding Assessed Tax Amount, excluding tax collected from customer, of alternative revenue programs and leases revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise. Contested amount of fines imposed ContestedAmountOfFinesImposed Contested amount of fines imposed by the Minnesota Office of Pipeline Safety. Number of Common stock held by the savings plan (in shares) Number Of Shares In Common Stock Held By Savings Plan The number of shares of the entity's common stock held by the savings plan Non-current assets held for sale Total non-current assets held for sale Disposal Group, Including Discontinued Operation, Assets, Noncurrent Cash Flow Hedging [Member] Cash Flow Hedging [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in June 2022 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringinJune2022 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in June 2022 Carrying amount [Member] Reported Value Measurement [Member] Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Revenue Recognition [Text Block] Revenue from Contract with Customer [Text Block] Ownership percentage of equity method investment Limited partner ownership interest Equity Method Investment, Ownership Percentage Third Quarter 2020 [Member] Third Quarter 2020 [Member] Third Quarter 2020 Other current liabilities Increase (Decrease) in Other Current Liabilities Non-trading derivative liabilities Disposal Group, Including Discontinued Operation, Non-trading derivative liabilities, non-current Disposal Group, Including Discontinued Operation, Non-trading derivative liabilities, non-current Dividends declared per share Preferred stock dividends declared per share Preferred Stock, Dividends Per Share, Declared Amortization of net loss Actuarial losses (2) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Partner Type of Partners' Capital Account, Name [Domain] Partner Type of Partners' Capital Account, Name [Domain] Actuarial (gain) loss (1) Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Increase (decrease) in tax expense resulting from: Change In Tax Expense Abstract Long-term Debt, Fair Value Long-term Debt, Fair Value Limited Partners' Capital Account by Class [Axis] Limited Partners' Capital Account by Class [Axis] Inventory Inventory, Policy [Policy Text Block] Income tax expense (benefit) Total income tax expense (benefit) Income Tax Expense (Benefit) Income Tax Expense (Benefit) Year that the cost trend rates reach the ultimate trend rate Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate Percentage on limitation of debt to total capitalization under covenant (in hundredths) Percentage on limitation of debt to total capitalization under covenant (in hundredths) Percentage on limitation of debt to total capitalization under covenant. Cash, Cash Equivalents and Restricted Cash at Beginning of Year Cash, Cash Equivalents and Restricted Cash at End of Year Total cash, cash equivalents and restricted cash shown in Statements of Consolidated Cash Flows Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Goodwill impairment Disposal Group, Including Discontinued Operation, Goodwill Impairment Loss Disposal Group, Including Discontinued Operation, Goodwill Impairment Loss Schedule of Maturities of Long-term Debt [Table Text Block] Schedule of Maturities of Long-term Debt [Table Text Block] Revenue increase Public Utilities, Requested Rate Increase (Decrease), Amount Long-term Purchase Commitment [Table] Long-term Purchase Commitment [Table] Local Phone Number Local Phone Number Business Acquisition, Pro Forma Information [Table Text Block] Business Acquisition, Pro Forma Information [Table Text Block] Cash paid to acquire Vectren Payments to Acquire Businesses, Gross Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Depreciation and amortization Equity Method Investment Summarized Financial Information Depreciation And Amortization The amount of the depreciation and amortization reported by an equity method investment of the entity. Finite-lived Intangible Assets Amortization Expense [Table Text Block] Finite-lived Intangible Assets Amortization Expense [Table Text Block] Limited partner interest units held Variable Interest Entity, Ownership, Shares Represents the number of shares owned of the variable interest entity as of the balance sheet date Incremental share-based awards expense recorded Share-based Payment Arrangement, Accelerated Cost Income tax expense (benefit) from discontinued operations Income tax expense (benefit) Discontinued Operation, Tax Effect of Discontinued Operation Derivative [Line Items] Derivative [Line Items] Liability recorded for remediation of Minnesota sites Accrual for Environmental Loss Contingencies Interim Period, Costs Not Allocable [Domain] Interim Period, Costs Not Allocable [Domain] Schedule of Subsequent Events [Table Text Block] Schedule of Subsequent Events [Table Text Block] Investment grade or above [Member] Corporate Debt Securities Investment Grade Or Above Member This category includes information about debt securities with an investment grade or higher rating issued by a corporate entity with a promise of repayment. Vectren [Member] Vectren [Member] Vectren [Member] Outstanding debt balance Long-term Debt, Gross Long-term Debt, Gross Decreases related to tax positions of prior years Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Previous Dividend or Distribution [Member] Previous Dividend or Distribution [Member] Previous Dividend or Distribution [Member] Opening balance as of December 31, 2019 Closing balance as of December 31, 2020 Contract with Customer, Liability Related Party Transaction [Domain] Related Party Transaction [Domain] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Senior notes 3.55% to 6.625% due 2021 to 2047 Senior Notes Due Range 2 [Member] Senior Notes Due Range 2 [Member] Loss (gain) on indexed debt securities Indexed Debt Securities, Gain (Loss) This item represents the net total realized and unrealized gain (loss) included in earnings for the period related to indexed debt securities. Size of credit facility Line of Credit Facility, Maximum Borrowing Capacity Reclassification of net deferred loss from cash flow hedges (3) Reclassification of net deferred loss from cash flow hedges (3) Reclassification of net deferred losses from cash flow hedges to regulatory asset and regulatory liability, before tax Assumptions used to determine net periodic benefit (income) cost Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis] Award Type [Axis] Award Type [Axis] Guarantees & Product Warranties [Abstract] Performance Guarantees & Product Warranties [Abstract] Performance Guarantees & Product Warranties [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Prepaid Expenses and Other Current Assets [Member] Prepaid Expenses and Other Current Assets [Member] Subordinated note cash exchangeable percentage of fair value Subordinated Note Cash Exchangeable Percentage Of Fair Value The percentage of the fair value of the referenced TW Common shares attributable to each note and the percentage of composite fair value each note can be exchanged for cash. Amortization of deferred financing costs Amortization of Debt Issuance Costs Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Nonvested Distribution to ZENS holders Distribution To ZENS Holders This represents a distribution of cash to ZENS holders during the period in accordance with the terms of the ZENS. 2021 Purchase Obligation, to be Paid, Year One Materials and supplies Inventory, Raw Materials and Supplies, Gross Retained Earnings [Member] Retained Earnings [Member] Preferred stock outstanding (in shares) Balance, beginning of year Balance, end of year Preferred Stock, Shares Outstanding Net affiliate service charges (billings) Net affiliate service charges (billings) Amount of net service charges from (billings to) related party during the period, excluding transactions that are eliminated in consolidated or combined financial statements. Measurement Basis [Axis] Measurement Basis [Axis] Revisions in estimates (2) Asset Retirement Obligation, Revision of Estimate Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Schedule of Net Benefit Costs [Table Text Block] Schedule of Net Benefit Costs [Table Text Block] Summary of Significant Accounting Policies [Text Block] Significant Accounting Policies [Text Block] Net Cash Provided by (Used in) Investing Activities Net Cash Provided by (Used in) Investing Activities Purchase of investments Payments to Acquire Investments Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block] Lessor, Operating Lease, Payment to be Received, Fiscal Year Maturity [Table Text Block] Award Type [Domain] Award Type [Domain] Current liabilities-other Liability, Defined Benefit Plan, Current Other Liabilities: Liabilities, Noncurrent [Abstract] Distribution per share of common units Distribution per share of common units Per share or per unit amount of distributions received from an equity method investment. Aggregate fair value of derivatives with credit-risk-related contingent features in a liability position Derivative, Net Liability Position, Aggregate Fair Value Performance and Stock Awards [Member] Performance and Stock Awards [Member] Performance and Stock Awards [Member] Discontinued Operations and Disposal Groups [Abstract] Property, Plant and Equipment [Text Block] Property, Plant and Equipment Disclosure [Text Block] Preferred Stock, Convertible, Stock Price Trigger Preferred Stock, Convertible, Stock Price Trigger Price of the entity's common stock which would be required to be attained for the conversion feature embedded in the preferred stock to become effective. Continuing Operations [Member] Continuing Operations [Member] Reportable Subsegments [Member] Reportable Subsegments [Member] AFUDC equity (2) Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Interest and taxes accrued Increase Decrease Interest and taxes accrued Increase (decrease) in interest and taxes accrued. Earnings Per Share (CenterPoint Energy) [Text Block] Earnings Per Share [Text Block] Pension Plan [Member] Pension Plan [Member] Discount rate (2) Discount Rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Operating income Equity Method Investment, Summarized Financial Information, Operating Income (Loss) The amount of operating income (loss) reported by an equity method investment of the entity. Natural Gas Expenses [Member] Natural Gas Expenses [Member] Represents natural gas expenses, including transportation and storage costs. Current Liabilities: Liabilities, Current [Abstract] Federal statutory income tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Cash Flows from Financing Activities: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Accretion expense (1) Asset Retirement Obligation, Accretion Expense New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Proceeds from Lines of Credit Proceeds from Lines of Credit Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Earnings Per Share, Basic [Abstract] Earnings Per Share, Basic [Abstract] Short-term Investments Short-term Investments Percentage on limitation of debt to total capitalization under covenant amended (in hundredths) Percentage on limitation of debt to total capitalization under covenant amended (in hundredths) Temporary increased percentage on limitation of debt to total capitalization under covenant (in hundredths) Share-Based Compensation Arrangement By Award, Weighted Average Grant Date Fair Value, Grant Date Intrinsic Value, and Vested Grant Date Fair Value [Table Text Block] Schedule Of Share Based Compensation Arrangement By Award, Weighted-average Grant Date Fair Value, Grant Date Intrinsic Value, and Vested Grant Date Fair Value [Table Text Block] Schedule Of Share-Based Compensation Arrangement By Award, Weighted-average Grant Date Fair Value, Grant Date Intrinsic Value, and Vested Grant Date Fair Value [Table Text Block]