Statement [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Series A Preferred Stock [Member] Series A Preferred Stock [Member] Series B Preferred Stock [Member] Series B Preferred Stock [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Houston Electric [Member] Houston Electric [Member] Houston Electric [Member] 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. Statement [Line Items] Statement [Line Items] Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Current Assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Investment in marketable securities Marketable Securities, Current Accounts receivable Accounts Receivable, Net, Current Accounts and notes receivable, net Accounts and Notes Receivable, Net Accounts and notes receivable—affiliated companies Due from Related Parties, Current Accrued unbilled revenues Unbilled Receivables, Current Materials and supplies Public Utilities, Inventory Natural gas and coal inventory Energy Related Inventory, Natural Gas in Storage Materials and supplies Inventory, Raw Materials and Supplies, Gross Non-trading derivative assets Derivative Asset, Current Taxes receivable Income Taxes Receivable, Current Prepaid expense and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current Property, Plant and Equipment, net Property, Plant and Equipment, Net Other Assets: Noncurrent Assets, Other Than Property Plant and Equipment [Abstract] Noncurrent Assets, Other Than Property Plant and Equipment [Abstract] Goodwill Goodwill Regulatory assets Regulatory Assets, Noncurrent Non-trading derivative assets Derivative Asset, Noncurrent Investment in unconsolidated affiliates Equity Method Investments Preferred units - unconsolidated affiliate Cost Method Investments Intangible Assets, Net (Excluding Goodwill) Intangible Assets, Net (Excluding Goodwill) Other Other Assets, Noncurrent 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. Total Assets Assets LIABILITIES AND SHAREHOLDERS’ EQUITY Liabilities and Equity [Abstract] Current Liabilities: Liabilities, Current [Abstract] 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. Indexed debt, net Indexed Debt Current Current portion of other long-term debt Other Long-term Debt, Current Indexed debt securities derivative Indexed debt securities derivative Accounts payable Accounts Payable, Current Accounts and notes payable—affiliated companies Due to Related Parties, Current Taxes accrued Taxes Payable, Current Interest accrued Interest Payable, Current Dividends accrued Dividends Payable, Current Customer deposits Customer Deposits, Current Non-trading derivative liabilities Derivative Liability, Current Other Other Liabilities, Current Total current liabilities Liabilities, Current Other Liabilities: Liabilities, Noncurrent [Abstract] Deferred income taxes, net Deferred Tax Liabilities, Net, Noncurrent Non-trading derivative liabilities Derivative Liability, Noncurrent Benefit obligations Liability, Defined Benefit Plan, Noncurrent Regulatory liabilities Regulatory Liability, Noncurrent Other Other Liabilities, Noncurrent Total other liabilities Liabilities, Other than Long-term Debt, Noncurrent Long-term Debt: Long-term Debt, Excluding Current Maturities [Abstract] 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. Other long-term debt, net Other Long-term Debt, Noncurrent Total long-term debt, net Long-term Debt, Excluding Current Maturities Commitments and Contingencies (Note 16) Commitments and Contingencies Shareholders’ Equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [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. Preferred Stock Preferred Stock, Value, Issued Common stock Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Total shareholders’ equity Stockholders' Equity Attributable to Parent Total Liabilities and Shareholders’ Equity Liabilities and Equity Earnings Per Share [Abstract] Earnings Per Share (CenterPoint Energy) [Text Block] Earnings Per Share [Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Other Intangibles (CenterPoint Energy and CERC) [Text Block] Goodwill and Intangible Assets Disclosure [Text Block] Supplemental Cash Flow Elements [Abstract] Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Income Statement Location [Axis] Income Statement Location [Axis] Derivative Instruments, Gain (Loss) by Income Statement Location [Domain] Income Statement Location [Domain] Gains (Losses) in Revenue [Member] Sales [Member] Natural Gas Expenses [Member] Natural Gas Expenses [Member] Represents natural gas expenses, including transportation and storage costs. Gains (Losses) in Other Income (Expense) [Member] Nonoperating Income (Expense) [Member] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedging [Member] Cash Flow Hedging [Member] Fair Value Hedging [Member] Fair Value Hedging [Member] Position [Axis] Position [Axis] Position [Domain] Position [Domain] Long [Member] Long [Member] Hedging Designation [Axis] Hedging Designation [Domain] Designated as Hedging Instrument [Member] Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Current Assets [Member] Line item in the statement of financial position in which the fair value amounts of the derivative instruments are included. Other Noncurrent Assets [Member] Other Noncurrent Assets [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. Other Noncurrent Liabilities [Member] Other Noncurrent Liabilities [Member] External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Domain] External Credit Rating by Grouping [Domain] External Credit Rating, Investment Grade [Member] External Credit Rating, Investment Grade [Member] Derivative, by Nature [Axis] Derivative Instrument [Axis] Derivative, Name [Domain] Derivative Contract [Domain] Interest Rate Contract [Member] Interest Rate Contract [Member] Energy Related Derivative [Member] Energy Related Derivative [Member] IDS Derivative [Member] IDS Derivative [Member] Derivative instrument related to indexed debt securities Derivative Contract [Domain] Counterparty Name [Axis] Counterparty Name [Axis] Counterparty Name [Domain] Counterparty Name [Domain] Energy Marketers [Member] Energy Marketers [Member] Derivative asset amounts associated with energy marketers. Retail End Users [Member] Retail End Users [Member] Derivative asset amounts associated with retail end users. Derivative Instrument [Axis] Derivative [Line Items] Derivative [Line Items] Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract] Derivative Assets (Liabilities), at Fair Value, Net, by Balance Sheet Classification [Abstract] Derivative Assets Fair Value Derivative Asset, Fair Value, Gross Asset Derivative Liabilities Fair Value Derivative Liability, Fair Value, Gross Liability Derivative gross volume notional amount (in Bcf) Derivative, Nonmonetary Notional Amount, Volume Derivative Asset Derivative Asset Cumulative Amount of Fair Value Hedging Adjustment Included in the Carrying Amount of Hedged Item Deferred (Gain) Loss on Discontinuation of Fair Value Hedge Gross Amounts Recognized Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement Gross Amounts Offset Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset Gross Amounts Recognized Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement Gross Amounts Offset Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset Derivative Liability Derivative Liability Gross Amounts Recognized Derivative, Fair Value, Net Gross Amounts Offset in the Consolidated Balance Sheets Derivative, Fair Value, Offsets, Net Total of gross amounts offset, net. Net Amount Presented in the Consolidated Balance Sheets Derivative Assets (Liabilities), at Fair Value, Net Income Statement Impact of Derivative Activity [Abstract] Income Statement Impact of Derivative Activity [Abstract] Income Statement Impact of Derivative Activity [Abstract] Total amounts presented in the statements of income in which the effects of hedges are recorded Cost of Goods and Services Sold Change in unrealized gain (loss) on fair value hedging instruments Change in Unrealized Gain (Loss) on Fair Value Hedging Instruments Amounts excluded from effectiveness testing recognized in earnings immediately Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net Gain (loss) on derivative instruments not designated as hedging instruments Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Derivative, Credit Risk Related Contingent Features [Abstract] Derivative, Credit Risk Related Contingent Features [Abstract] Aggregate fair value of derivatives containing material adverse change provisions in a net liability position Derivative, Net Liability Position, Aggregate Fair Value Fair value of collateral already posted Collateral Already Posted, Aggregate Fair Value Additional collateral required to be posted if credit risk contingent features triggered Additional Collateral, Aggregate Fair Value Credit Risk Derivatives, at Fair Value, Net [Abstract] Total credit risk of counterparties Credit Risk Derivative Assets, at Fair Value Revenue from Contract with Customer [Abstract] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Infrastructure Services [Member] Infrastructure Services [Member] Infrastructure Services [Member] Corporate and Other [Member] Corporate and Other [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Amount Revenue Recognition [Text Block] Revenue from Contract with Customer [Text Block] Indexed Debt Securities [Abstract] Indexed Debt Securities [Abstract] 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] Organization, Consolidation and Presentation of Financial Statements [Abstract] Background [Text Block] Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Debt Disclosure [Abstract] Schedule of Short-term Borrowings and Long-term Debt [Table Text Block] Schedule of Debt [Table Text Block] Schedule of Revolving Credit Facilities and Utilization of Such Facilities [Table Text Block] Schedule of Line of Credit Facilities [Table Text Block] Schedule of Maturities of Long-term Debt [Table Text Block] Schedule of Maturities of Long-term Debt [Table Text Block] Regulated Operations [Abstract] Public Utilities General Disclosures [Table] Public Utilities General Disclosures [Table] Regulatory Asset [Axis] Regulatory Asset [Axis] Regulatory Asset [Domain] Regulatory Asset [Domain] Rate Case Expense [Member] Rate Case Expense [Member] Rate Case Expense [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Domain] Public Utilities, Regulatory Proceeding [Domain] CenterPoint Energy Houston Electric 2019 Rate Case [Member] CenterPoint Energy Houston Electric 2019 Rate Case [Member] CenterPoint Energy Houston Electric 2019 Rate Case [Member] Houston Electric Stipulation and Settlement Agreement [Member] Houston Electric Stipulation and Settlement Agreement [Member] Houston Electric Stipulation and Settlement Agreement [Member] Regulatory Agency [Axis] Regulatory Agency [Axis] Regulatory Agency [Domain] Regulatory Agency [Domain] Public Utility Commission of Texas [Member] Public Utility Commission of Texas [Member] Public Utility Commission of Texas [Member] Public Utilities, General Disclosures [Line Items] Public Utilities, General Disclosures [Line Items] Revenue increase Public Utilities, Requested Rate Increase (Decrease), Amount Rate base Public Utilities, Rate Base Public Utilities, Rate Base Debt capital structure Public Utilities, Requested Debt Capital Structure, Percentage Equity capital structure Public Utilities, Requested Equity Capital Structure, Percentage Return on equity Public Utilities, Requested Return on Equity, Percentage Unprotected Excess Deferred Income Tax Unprotected Excess Deferred Income Tax Unprotected Excess Deferred Income Tax resulting from the TCJA Non-current regulatory assets General mortgage bonds used as collateral General mortgage bonds used as collateral General mortgage bonds used as collateral Quarterly Financial Information Disclosure [Abstract] Unaudited Quarterly Information [Text Block] Quarterly Financial Information [Text Block] Disclosure of Stock-Based Incentive Compensation Plans and Employee Benefit Plans [Abstract] Disclosure of Stock-Based Incentive Compensation Plans and Employee Benefit Plans [Abstract] Concentration Risk [Table] Concentration Risk [Table] Concentration Risk by Benchmark [Axis] Concentration Risk Benchmark [Axis] Concentration Risk Benchmark [Domain] Concentration Risk Benchmark [Domain] Workforce Subject to Collective Bargaining Arrangements Expiring in May 2020 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in May 2020 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in May 2020 Workforce Subject to Collective Bargaining Arrangements Expiring in March and May 2021 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in March and May 2021 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in March and May 2021 Workforce Subject to Collective Bargaining Arrangements Expiring in April 2020 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in April 2020 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in April 2020 Workforce Subject to Collective Bargaining Arrangements Expiring in December 2020 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in December 2020 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in December 2020 Workforce Subject to Collective Bargaining Arrangements Expiring in June and July 2022 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringinJuneandJuly2022 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in June and July 2022 Workforce Subject to Collective Bargaining Arrangements Expiring in September 2021 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringinSeptember2021 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringinSeptember2021 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring in October 2021 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringinOctober2021 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringinOctober2021 [Member] Workforce Subject to Collective Bargaining Arrangements Expiring Various Dates in 2020 to 2022 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringVariousDatesin2020to2022 [Member] WorkforceSubjecttoCollectiveBargainingArrangementsExpiringVariousDatesin2020to2022 [Member] Workforce Subject to Collective Bargaining Arrangements [Member] Workforce Subject to Collective Bargaining Arrangements [Member] Collective Bargaining Arrangement [Axis] Collective Bargaining Arrangement [Axis] Collective Bargaining Arrangement [Domain] Collective Bargaining Arrangement [Domain] Employees Subject To Collective Bargaining Agreements [Member] Employees Subject To Collective Bargaining Agreements [Member] Represents the employees subject to collective bargaining agreements. Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Labor Force Concentration Risk [Member] Labor Force Concentration Risk [Member] Concentration Risk [Line Items] Concentration Risk [Line Items] 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) Concentration Risk, Percentage Concentration Risk, Percentage Derivative Instruments [Text Block] Derivative Instruments and Hedging Activities Disclosure [Text Block] 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. Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension Plan [Member] Pension Plan [Member] Postretirement Benefits [Member] Other Postretirement Benefits Plan [Member] Non-qualified Pension Plan [Member] Other Pension Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Share-Based Compensation, Activity [Table Text Block] Share-based Compensation, Activity [Table Text Block] 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] Schedule of Net Benefit Costs [Table Text Block] Schedule of Net Benefit Costs [Table Text Block] Schedule of Assumptions Used [Table Text Block] Schedule of Assumptions Used [Table Text Block] Schedule of Net Pension and Post-retirement Benefit Costs [Table Text Block] Schedule of Defined Benefit Plans Disclosures [Table Text Block] Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block] Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block] Schedule of Multiemployer Plans [Table Text Block] Schedule of Multiemployer Plans [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] 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] 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 Schedule of Allocation of Plan Assets [Table Text Block] Schedule of Allocation of Plan Assets [Table Text Block] Benefit Plan Contributions [Table Text Block] Benefit Plan Contributions [Table Text Block] Benefit Plan Contributions [Table Text Block] Schedule of Expected Benefit Payments [Table Text Block] Schedule of Expected Benefit Payments [Table Text Block] Defined Contribution Plan Disclosures [Table Text Block] Defined Contribution Plan Disclosures [Table Text Block] Other Benefit Plans [Table Text Block] Other Benefit Plans [Table Text Block] Other Benefit Plans [Table Text Block] Other Employee Matters [Table Text Block] Other Employee Matters [Table Text Block] Other Employee Matters [Table Text Block] Segment Reporting [Abstract] Financial Data for Business Segments [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block] Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block] Midstream Investments [Table Text Block] Midstream Investments [Table Text Block] Tabular presentation of equity earnings and equity investment related to Midstream Investments for the period [Table Text Block] Revenues by Products and Services [Table Text Block] Revenue from External Customers by Products and Services [Table Text Block] Disaggregation of Revenue [Table Text Block] Disaggregation of Revenue [Table Text Block] Contract with Customer, Asset and Liability [Table Text Block] Contract with Customer, Asset and Liability [Table Text Block] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block] Schedule of Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block] Fair Value of Derivative Instruments [Table Text Block] Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Offsetting of Natural Gas Derivative Assets and Liabilities [Table Text Block] Derivative Instruments, Offsetting Assets and Liabilities [Table Text Block] Tabular disclosure of derivative assets and liabilities that are subject to offsetting, including master netting arrangements. Income Statement Impact of Derivative Activity [Table Text Block] Derivative Instruments, Gain (Loss) [Table Text Block] Credit Quality of Counterparties [Table Text Block] Disclosure of Credit Derivatives [Table Text Block] Stockholders' Equity Note [Abstract] Equity (CenterPoint Energy) [Text Block] Stockholders' Equity Note Disclosure [Text Block] Reportable Segments [Text Block] Segment Reporting Disclosure [Text Block] Leases [Abstract] Lessee, Leases [Policy Text Block] Lessee, Leases [Policy Text Block] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Domain] Subsegments Consolidation Items [Domain] Reportable Subsegments [Member] Reportable Subsegments [Member] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Intersegment Eliminations [Member] Intersegment Eliminations [Member] 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. 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 Natural Gas Distribution [Member] 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. 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. Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenue from contracts Revenue from Contract with Customer, Excluding Assessed Tax Derivatives income Derivative Income Loss Revenue derived from derivative natural gas sales contracts, asset management agreements and gains (losses) associated with weather hedge derivatives. Other (3) 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. Total revenues Revenues Statement [Table] Product and Service [Axis] Product and Service [Axis] Product and Service [Domain] Product and Service [Domain] Electric Delivery [Member] Electric Delivery [Member] Represents revenues from electric transmission and distribution sales Retail Electric Sales [Member] Retail Electric Sales [Member] Retail Electric Sales [Member] Wholesale Electric Sales [Member] Wholesale Electric Sales [Member] Wholesale Electric Sales [Member] Retail Gas Sales [Member] Retail Gas Sales [Member] Represents revenue from retail gas sales Wholesale Gas Sales [Member] Wholesale Gas Sales [Member] Represents revenue from wholesale gas sales Gas Transportation and Processing [Member] Gas Transportation and Processing [Member] Represents revenues from gas transportation and processing Energy Products and Services [Member] Energy Products Or Services [Member] Represents revenue from energy products and services Revenues by Products and Services: Product And Service Abstract Each product and service of an entity by various financial or nonfinancial attributes. Revenues Net income Net Income (Loss) Attributable to Parent Other comprehensive income (loss): Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Adjustment to pension and other postretirement plans Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax and Reclassification Adjustment, Attributable to Parent Net deferred gain (loss) from cash flow hedges Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Reclassification of deferred loss from cash flow hedges realized in net income (net of tax expense of $-0-, $-0- and $-0-, respectively) Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Other comprehensive loss from unconsolidated affiliates, net of tax Other comprehensive loss from unconsolidated affiliates, net of tax Other comprehensive loss from unconsolidated affiliates, net of tax Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income ComprehensiveIncomeNetofTaxBeforePreferredStockDiv Total comprehensive income before preferred stock dividend requirements. Preferred stock dividend requirement Preferred Stock Dividends and Other Adjustments Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Statement of Stockholders' Equity [Abstract] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Preferred Stock [Member] Preferred Stock [Member] Common Stock [Member] Common Stock [Member] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Retained Earnings [Member] Retained Earnings [Member] AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Adjustments for New Accounting Principle, Early Adoption [Member] Adjustments for New Accounting Principle, Early Adoption [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance, beginning of year Preferred Stock, Shares Outstanding Issuances of stock Stock Issued During Period, Shares, New Issues Balance, end of year Balance, beginning of year Common Stock, Shares, Outstanding Issuances related to benefit and investment plans Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Balance, end of year Balance, beginning of year Issuances related to benefit and investment plans Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Issuances of stock Stock Issued During Period, Value, New Issues Contribution From Parent Contribution From Parent Contribution From Parent Capital distribution associated with the Internal Spin Other Significant Noncash Transaction, Value of Consideration Given Other Adjustments to Additional Paid in Capital, Other Common Stock dividends declared ($0.8625, $1.1200 and $1.3475 per share, respectively) Dividends, Common Stock Preferred stock dividends declared Dividends, Preferred Stock, Cash Dividend to parent Dividends, Cash Adoption of ASU 2018-02 Cumulative Effect of New Accounting Principle in Period of Adoption Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax Balance, end of year Schedule of Goodwill [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Vectren [Member] Vectren [Member] Vectren [Member] Income Statement Location [Domain] Depreciation and amortization expense [Member] Depreciation and amortization expense [Member] Depreciation and amortization expense [Member] Non-utility cost of revenues [Member] Cost of Sales [Member] Vectren acquisition [Member] Vectren acquisition [Member] Vectren acquisition [Member] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Customer Relationships [Member] Customer Relationships [Member] Covenants Not To Compete [Member] Noncompete Agreements [Member] Trade Names [Member] Trade Names [Member] Construction backlog [Member] Order or Production Backlog [Member] Operation and maintenance agreements [Member] Operation and maintenance agreements [Member] Operation and maintenance agreements [Member] Other [Member] Other Intangible Assets [Member] Goodwill [Line Items] Goodwill [Line Items] Goodwill Goodwill, Acquired During Period Goodwill, Acquired During Period Goodwill impairment charge recorded from annual impairment test Goodwill, Impairment Loss Accumulated goodwill impairment charge recorded in 2012 Goodwill, Impaired, Accumulated Impairment Loss Finite-Lived Intangible Assets, Net [Abstract] Finite-Lived Intangible Assets, Net [Abstract] Gross Carrying Amount Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Net Balance Finite-Lived Intangible Assets, Net Amortization expense of intangible assets recorded in Depreciation and amortization (1) (2) Amortization of Intangible Assets 2020 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2024 Finite-Lived Intangible Assets, Amortization Expense, Year Five Deferred Tax Liabilities, Net, Noncurrent Goodwill, Impairment Loss, Net of Tax Goodwill, Impairment Loss, Net of Tax Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Bond Companies [Member] Bond Companies [Member] Bond Companies [Member] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Cash and Cash Equivalents [Member] Cash and Cash Equivalents [Member] Prepaid Expenses and Other Current Assets [Member] Prepaid Expenses and Other Current Assets [Member] Other, net [Member] Other Nonoperating Income (Expense) [Member] Interest, net of capitalized interest Interest Paid, Excluding Capitalized Interest, Operating Activities Income taxes (refunds), net Income Taxes Paid, Net Accounts payable related to capital expenditures Capital Expenditures Incurred but Not yet Paid Capital distribution associated with the Internal Spin 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 Restricted cash Restricted Cash and Cash Equivalents Total cash, cash equivalents and restricted cash shown in Statements of Consolidated Cash Flows Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Temporary investments Short-term Investments Interest income Interest Income (Expense), Nonoperating, Net Interest Income, Other Interest Income, Other Property, Plant and Equipment [Abstract] Schedule of Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] SIGECO [Member] SIGECO [Member] SIGECO [Member] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Electric Transmission and Distribution [Member] Electric Transmission and Distribution Equipment [Member] Electric Generation Equipment [Member] Electric Generation Equipment [Member] Electric Transmission [Member] Electric Transmission [Member] Electric Distribution [Member] Electric Distribution [Member] Natural Gas Distribution [Member] Gas Distribution Equipment [Member] Energy Services [Member] Gas Transmission Equipment [Member] Infrastructure Services [Member] Other Machinery and Equipment [Member] Other property [Member] Other Capitalized Property Plant and Equipment [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Weighted Average [Member] Weighted Average [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Property, Plant and Equipment, Net, by Type [Abstract] Weighted Average Useful Lives Property, Plant and Equipment, Useful Life Property, Plant and Equipment, Gross Property, Plant and Equipment, Gross Accumulated Depreciation & Amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, Plant and Equipment, Net SIGECO's share of cost of Warrick Unit 4 Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service SIGECO's share of accumulated depreciation of Warrick Unit 4 Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation Depreciation and Amortization [Abstract] Depreciation, Depletion and Amortization [Abstract] Depreciation Depreciation Amortization of securitized regulatory assets Amortization of Regulatory Asset Other amortization Amortization Total Depreciation, Depletion and Amortization Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Beginning balance Asset Retirement Obligation Asset Retirement Obligation Addition from Merger with Vectren Asset Retirement Obligation Addition from Merger with Vectren Asset Retirement Obligation Addition from Merger with Vectren Accretion expense (1) Asset Retirement Obligation, Accretion Expense Revisions in estimates (2) Asset Retirement Obligation, Revision of Estimate Ending balance Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs, by Report Line [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. Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis] Award Type [Axis] Award Type [Domain] Equity Award [Domain] Performance Awards [Member] Performance Shares [Member] Stock Awards [Member] Stock Awards Member Stock awards within the entity's long-term stock incentive plan. Performance and Stock Awards [Member] Performance and Stock Awards [Member] Performance and Stock Awards [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Shares authorized for issuance under long-term incentive plans (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Employee Service Share-based Compensation, Aggregate Disclosures [Abstract] Employee Service Share-based Compensation, Aggregate Disclosures [Abstract] LTIP compensation expense Allocated Share-based Compensation Expense Income tax benefit recognized related to LTIPs Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Actual tax benefit realized for tax deductions Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options 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] 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] Nonvested, beginning of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Forfeited or cancelled (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Vested and released to participants (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Nonvested, end of period (in shares) Weighted average grant date fair value, nonvested, beginning 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 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 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 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 Weighted average grant date fair value, nonvested, end of period (in dollars per share) 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 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 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 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. Unrecognized compensation cost related to non-vested performance and stock awards Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Weighted average period of recognition (in years) Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Lease Disclosure [Table] Lease Disclosure [Table] Lease Disclosure [Table] Lease Disclosure [Line Items] Lease Disclosure [Line Items] [Line Items] for Lease Disclosure [Table] Lease, Cost [Abstract] Lease, Cost [Abstract] Operating lease cost Operating Lease, Cost Short-term lease cost Short-term Lease, Cost Variable lease cost Variable Lease, Cost Total lease cost Lease, Cost Operating Leases, Lease Income [Abstract] Operating Leases, Lease Income [Abstract] Operating lease income Operating Lease, Lease Income, Lease Payments Variable lease income Operating Lease, Variable Lease Income Total lease income Operating Lease, Lease Income Assets and Liabilities, Lessee [Abstract] Assets and Liabilities, Lessee [Abstract] Operating ROU assets (1) Operating Lease, Right-of-Use Asset Total leased assets Lease Right-Of-Use Asset Total Leased Right-Of-Use-Assets Current operating lease liability (2) Operating Lease, Liability, Current Non-current operating lease liability (3) Operating Lease, Liability, Noncurrent Total leased liabilities Operating Lease, Liability Weighted-average remaining lease term (in years) - operating leases Operating Lease, Weighted Average Remaining Lease Term Weighted-average discount rate - operating leases Operating Lease, Weighted Average Discount Rate, Percent Operating Lease Liabilities, Payments Due [Abstract] Operating Lease Liabilities, Payments Due [Abstract] 2020 Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months 2021 Lessee, Operating Lease, Liability, Payments, Due Year Two 2022 Lessee, Operating Lease, Liability, Payments, Due Year Three 2023 Lessee, Operating Lease, Liability, Payments, Due Year Four 2024 Lessee, Operating Lease, Liability, Payments, Due Year Five 2025 and beyond Lessee, Operating Lease, Liability, Payments, Due after Year Five Total lease payments Lessee, Operating Lease, Liability, Payments, Due Less: Interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2019 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2020 Operating Leases, Future Minimum Payments, Due in Two Years 2021 Operating Leases, Future Minimum Payments, Due in Three Years 2022 Operating Leases, Future Minimum Payments, Due in Four Years 2023 Operating Leases, Future Minimum Payments, Due in Five Years 2024 and beyond Operating Leases, Future Minimum Payments, Due Thereafter Total (1) Operating Leases, Future Minimum Payments Due Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract] Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract] 2020 Lessor, Operating Lease, Payments to be Received, Next Twelve Months 2021 Lessor, Operating Lease, Payments to be Received, Two Years 2022 Lessor, Operating Lease, Payments to be Received, Three Years 2023 Lessor, Operating Lease, Payments to be Received, Four Years 2024 Lessor, Operating Lease, Payments to be Received, Five Years 2025 and beyond Lessor, Operating Lease, Payments to be Received, Thereafter Total lease payments to be received Lessor, Operating Lease, Payments to be Received Other Information Related to Leases [Abstract] Other Information Related to Leases [Abstract] Other Information Related to Leases [Abstract] Operating cash flows from operating leases included in the measurement of lease liabilities Operating Lease, Payments 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 Lease, Cost [Table Text Block] Lease, Cost [Table Text Block] Operating Lease, Lease Income [Table Text Block] Operating Lease, Lease Income [Table Text Block] Supplemental Balance Sheet Information Related To Leases [Table Text Block] Supplemental Balance Sheet Information Related To Leases [Table Text Block] SupplementalBalanceSheetInformationRelatedToLeases [Table Text Block] Lessee, Operating Lease, Liability, Maturity [Table Text Block] Lessee, Operating Lease, Liability, Maturity [Table Text Block] Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block] Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block] Other Information Related To Leases [Table Text Block] Other Information Related To Leases [Table Text Block] OtherInformationRelatedToLeases [Table Text Block] Accounting Policies [Abstract] Public Utilities General Disclosures [Table Text Block] Public Utilities General Disclosures [Table Text Block] 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. Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Principles of Consolidation Consolidation, Policy [Policy Text Block] Equity and Investments without a Readily Determinable Fair Value (CenterPoint Energy and CERC) Equity and Cost Method Investments, Policy [Policy Text Block] Revenues Revenue Recognition, Policy [Policy Text Block] 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. Guarantees Guarantees, Indemnifications and Warranties Policies [Policy Text Block] Long-lived Assets, Goodwill and Intangibles Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block] Assets Held for Sale and Discontinued Operations Discontinued Operations, Policy [Policy Text Block] Regulatory Assets and Liabilities Public Utilities, Policy [Policy Text Block] Depreciation and Amortization Expense Depreciation, Depletion, and Amortization [Policy Text Block] Capitalization of Interest and AFUDC Allowance for Funds Used During Construction, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Accounts Receivable and Allowance for Doubtful Accounts Trade and Other Accounts Receivable, Policy [Policy Text Block] Inventory Inventory, Policy [Policy Text Block] Derivative Instruments Derivatives, Policy [Policy Text Block] Investments in Equity Securities (CenterPoint Energy and CERC) Marketable Securities, Policy [Policy Text Block] Environmental Costs Environmental Costs, Policy [Policy Text Block] Cash and Cash Equivalents and Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Preferred Stock Dividends Stockholders' Equity Note, Redeemable Preferred Stock, Issue, Policy [Policy Text Block] Purchase Accounting Business Combinations and Other Purchase of Business Transactions, Policy [Policy Text Block] New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Subsequent Events [Abstract] Subsequent Events [Text Block] Subsequent Events [Text Block] Regulatory Accounting [Text Block] Public Utilities Disclosure [Text Block] 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. Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Pension and Other Postretirement Plans Costs [Member] Pension and Other Postretirement Plans Costs [Member] Other Regulatory Assets (Liabilities) [Member] Other Regulatory Assets (Liabilities) [Member] Catastrophic Event [Axis] Catastrophic Event [Axis] Catastrophic Event [Domain] Catastrophic Event [Domain] Hurricane Harvey [Member] Hurricane [Member] Amounts related to TCJA [Member] Amounts related to TCJA [Member] Amounts related to TCJA [Member] Asset Retirement Obligation Costs [Member] Asset Retirement Obligation Costs [Member] Regulatory Liability [Axis] Regulatory Liability [Axis] Regulatory Liability [Domain] Regulatory Liability [Domain] Removal Costs [Member] Removal Costs [Member] Other Current Liabilities [Member] Other Current Liabilities [Member] Schedule of Regulatory Assets and Liabilities [Line Items] Schedule Of Regulatory Assets And Liabilities [Line Items] -- None. No documentation exists for this element. -- Current regulatory assets (1) Regulatory Assets, Current Securitized regulatory assets Securitized Regulatory Transition Assets, Noncurrent 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 Unamortized loss on reacquired debt (3) Unamortized Loss Reacquired Debt, Noncurrent Total regulatory assets Regulatory Assets Current regulatory liabilities (6) Regulatory Liability, Current Non-current regulatory liabilities Total regulatory liabilities Regulatory Liabilities Total regulatory assets and liabilities, net Net Regulatory Assets 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 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 Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Investments [Member] Investments [Member] Accounts and notes receivable (payable) - affiliate companies [Member] Accounts and notes receivable (payable) - affiliate companies [Member] Accounts and notes receivable (payable) - affiliate companies [Member] Non-utility revenue [Member] Non-utility revenue [Member] unregulated operating revenue [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] 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. Related Party Transaction [Line Items] Related Party Transaction [Line Items] Money pool investments (borrowings) (1) MoneyPoolInvestments Represents investments in the parent company's money pool. Money Pool Borrowings MoneyPoolBorrowings Represents borrowings from the parent company's money pool. Weighted average interest rate Money Pool Investments Weighted Average Interest Rate Weighted average interest rate of outstanding investments in money pool. Interest income (expense), net (1) Interest Income (Expense) Net, Related Party Net interest income (expense) related to affiliate investments or borrowings Corporate service charges Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party 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. Pipeline construction and repair service charges Pipeline construction and repair service charges Pipeline construction and repair service charges related party transactions Natural gas sales Natural gas sales Natural gas sales to related party for use in electric generation activities Cash dividends paid to parent Payments of Dividends Capital distribution to parent associated with the Internal Spin (1) Statements of Consolidated Income Income Statement [Abstract] Revenues: Revenues [Abstract] Utility revenues Regulated Operating Revenue Non-utility revenues Unregulated Operating Revenue Total Expenses: Operating Expenses [Abstract] Utility natural gas, fuel and purchased power Utilities Operating Expense, Gas and Petroleum Purchased Non-utility cost of revenues, including natural gas Operation and maintenance Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses Depreciation and amortization Taxes other than income taxes Taxes, Miscellaneous Goodwill impairment Total Costs and Expenses Operating Income Operating Income (Loss) Other Income (Expense): Nonoperating Income (Expense) [Abstract] Gain (loss) on marketable securities Marketable Securities, Gain (Loss) Gain (loss) 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. Interest and other finance charges Interest and Debt Expense Interest on Securitization Bonds Interest on Transition and System Restoration Bonds Interest and debt related expenses associated with transition and system restoration bonds. Equity in earnings of unconsolidated affiliates, net Income (Loss) from Equity Method Investments Other, net Other Nonoperating Income (Expense) Total Nonoperating Income (Expense) Income Before Income Taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax expense (benefit) Income Tax Expense (Benefit) Income From Continuing Operations Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Income from discontinued operations (net of tax expense of $-0-, $46, and $104, respectively) Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Net Income Preferred stock dividend requirement Preferred Stock Dividends, Income Statement Impact Income Available to Common Shareholders Net Income (Loss) Available to Common Stockholders, Basic Basic Earnings Per Common Share Earnings Per Share, Basic Diluted Earnings Per Common Share Earnings Per Share, Diluted Weighted Average Common Shares Outstanding, Basic Weighted Average Number of Shares Outstanding, Basic Weighted Average Common Shares Outstanding, Diluted Weighted Average Number of Shares Outstanding, Diluted Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table Text Block] Schedule of Business Acquisitions, by Acquisition [Table Text Block] 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] Business Combination, Separately Recognized Transactions [Table Text Block] Business Combination, Separately Recognized Transactions [Table Text Block] Business Acquisition, Pro Forma Information [Table Text Block] Business Acquisition, Pro Forma Information [Table Text Block] Subsequent Event [Table] Subsequent Event [Table] Limited Partners' Capital Account by Class [Axis] Limited Partners' Capital Account by Class [Axis] Limited Partners' Capital Account, Class [Domain] Limited Partners' Capital Account, Class [Domain] Common Units [Member] Common Units [Member] Common Units [Member] Preferred Units by Name [Axis] Preferred Units by Name [Axis] Preferred Units, Class [Domain] Preferred Units, Class [Domain] Series A Preferred Units [Member] Series A Preferred Units [Member] Series A Preferred Units [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Enable Midstream Partners [Member] Enable Midstream Partners [Member] Enable Midstream Partners, LP Subsequent Event [Line Items] Subsequent Event [Line Items] Sales price of outstanding equity interests Sales price of outstanding equity interests Sales price of outstanding equity interests Declaration Date Dividends Payable, Date Declared Record Date Dividends Payable, Date of Record Payment Date Dividends Payable, Date to be Paid Common stock dividends declared per share Common Stock, Dividends, Per Share, Declared Preferred stock dividends declared per share Preferred Stock, Dividends Per Share, Declared Declaration Date Distribution Made to Limited Partner, Declaration Date Record Date Distribution Made to Limited Partner, Date of Record Payment Date Distribution Made to Limited Partner, Distribution Date Distributions Declared, Per Unit Distribution Made to Limited Partner, Distributions Declared, Per Unit Expected cash distribution on Enable Common Units Proceeds from Equity Method Investment, Distribution 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. Leases [Text Block] Lessee, Operating Leases [Text Block] Income tax expense (benefit) associated with discontinued operations Discontinued Operation, Tax Effect of Discontinued Operation Commitments and Contingencies Disclosure [Abstract] Long-term Purchase Commitment [Table Text Block] Long-term Purchase Commitment [Table Text Block] Schedule of Environmental Loss Contingencies by Site [Table Text Block] Schedule of Environmental Loss Contingencies by Site [Table Text Block] Fair Value Disclosures [Abstract] Fair Value Assets And Liabilities Measured On Recurring Basis Disclosure Items Table Fair Value Assets And Liabilities Measured On Recurring Basis Disclosure Items [Table] -- None. No documentation exists for this element. -- Hedged Item [Axis] Hedged Item [Axis] The asset or liability (or portion thereof) being hedged. Hedged Item [Domain] Hedged Item [Domain] [Domain] for The asset or liability (or portion thereof) being hedged. Natural gas inventory [Member] Natural gas inventory [Member] Natural gas inventory [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring [Member] Fair Value, Measurements, Recurring [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Fair Value, Inputs, Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Forward Contracts [Member] Forward Contracts [Member] Natural gas [Member] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Measurement Basis [Axis] Measurement Basis [Axis] Portion at Fair Value Measurement [Member] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying amount [Member] Reported Value Measurement [Member] Fair value [Member] Estimate of Fair Value Measurement [Member] Fair Value, assets and liabilities measured on recurring basis, financial statement captions Fair Value Assets And Liabilities Measured On Recurring Basis Financial Statement Captions [Line Items] Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Fair value inputs (price per MMBtu) Fair Value Inputs, Price Per MMBtu Fair value inputs used for valuing physical forward contracts using a discounted cash flow model, including illiquid forward price curve locations. Assets 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. Investments, including money market funds (2) Investments, Fair Value Disclosure Natural gas derivatives (3)(4) Natural gas derivative netting adjustment Natural gas derivatives (3)(4) Hedged portion of natural gas inventory Fair Value Hedge Assets Total derivative assets, netting adjustment Derivative Asset, Fair Value, Gross Liability Total assets Assets, Fair Value Disclosure Liabilities Liabilities [Abstract] Derivative liabilities Derivative liabilities, netting adjustment Derivative liabilities Fair Value Hedge Liabilities Fair Value Hedge Liabilities Total derivative liabilities, netting adjustment Derivative Liability, Fair Value, Gross Asset Total liabilities Financial Liabilities Fair Value Disclosure Derivative fair value offsets, net Fair value measurement using significant unobservable input (level 3) reconciliation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning balance Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis with Unobservable Inputs Total gains Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Gain (Loss) Included in Earnings Total settlements Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Settlements Transfers into Level 3 Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers into Level 3 Transfers out of Level 3 (1) Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers out of Level 3 Ending balance (2) The amount of total gains (losses) for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held at the reporting date (3) Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Estimated Fair Value of Financial Instruments Additional Fair Value Elements [Abstract] Long-term debt, including current maturities Long-term Debt, Fair Value Quarterly Financial Data [Table Text Block] Quarterly Financial Information [Table Text Block] Other Nonoperating Income (Expense) [Member] Statement, Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Other Postretirement Benefits Plan [Member] Pension and Postretirement Benefits [Abstract] Defined Benefit Plan [Abstract] Components of net periodic costs [Abstract] Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract] Service cost (1) Defined Benefit Plan, Service Cost Interest cost (2) Defined Benefit Plan, Interest Cost Expected return on plan assets (2) Defined Benefit Plan, Expected Return (Loss) on Plan Assets Amortization of prior service cost (2) Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Amortization of net loss (2) Defined Benefit Plan, Amortization of Gain (Loss) Settlement cost (2) (3) Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement Curtailment gain (2) (4) Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Curtailment Net periodic cost (credit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Assumptions used to determine net periodic benefit (income) cost Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Discount rate Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Expected return on plan assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Rate of Return on Plan Assets Rate of increase in compensation levels Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Change in benefit obligation [Roll Forward] Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Benefit obligation, beginning of year Defined Benefit Plan, Benefit Obligation Plan obligations assumed in Merger Defined Benefit Plan, Benefit Obligation, Business Combination Participant contributions Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant Benefits paid Defined Benefit Plan, Benefit Obligation, Benefits Paid Plan amendment Defined Benefit Plan, Benefit Obligation, Increase (Decrease) for Plan Amendment Actuarial (gain) loss (1) Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) Curtailment Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Curtailment Benefit obligation, end of year Change in plan assets [Rollforward] Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Fair value of plan assets, beginning of year Defined Benefit Plan, Plan Assets, Amount Plan assets assumed in Merger Defined Benefit Plan, Plan Assets, Business Combination Employer contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Participant contributions Defined Benefit Plan, Plan Assets, Contributions by Plan Participant Benefits paid Defined Benefit Plan, Plan Assets, Benefits Paid Actual investment return Defined Benefit Plan, Plan Assets, Increase (Decrease) for Actual Return (Loss) Fair value of plan assets, end of year Funded status of plan Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract] Funded status, end of year Defined Benefit Plan, Funded (Unfunded) Status of Plan Amounts recognized in balance sheets Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position [Abstract] Current liabilities-other Liability, Defined Benefit Plan, Current Other liabilities-benefit obligations Net liability, end of year Liability, Defined Benefit Plan Discount rate (2) Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Expected return on plan assets (3) Rate of increase in compensation levels Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase Interest crediting rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Weighted-Average Interest Crediting Rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Weighted-Average Interest Crediting Rate Health care cost trend rate assumed for the next year Defined Benefit Plan, Health Care Cost Trend Rate Assumed, Next Fiscal Year 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. Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Year that the cost trend rates reach the ultimate trend rate Defined Benefit Plan, Year Health Care Cost Trend Rate Reaches Ultimate Trend Rate Annualized individual discount rates based on time period, minimum Annualized individual discount rates based on time period, minimum Annualized individual discount rates based on time period, minimum Annualized individual discount rates based on time period, maximum Annualized individual discount rates based on time period, maximum Annualized individual discount rates based on time period, maximum Amounts recognized in accumulated other comprehensive loss Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax [Abstract] Unrecognized actuarial loss (gain) Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax Unrecognized prior service cost Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax Deferred Tax Benefit On Accumulated Other Comprehensive Income Deferred Tax Benefit On Accumulated Other Comprehensive Income Deferred Tax Benefit On Accumulated Other Comprehensive Income Net amount recognized in accumulated other comprehensive loss (gain) Accumulated Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), after Tax Changes in plan assets and benefit obligations recognized in other comprehensive income Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Net loss (gain) Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax Amortization of net loss Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax Prior service cost (2) Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax Total recognized in comprehensive income Other Comprehensive (Income) Loss, Defined Benefit Plan, before Tax, after Reclassification Adjustment, Attributable to Parent 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 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] Accumulated benefit obligation Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation Projected benefit obligation Defined Benefit Plan, Pension Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Projected Benefit Obligation Fair value of plan assets Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets Accumulated benefit obligation for all defined benefit pension plans Defined Benefit Plan, Accumulated Benefit Obligation Income Tax Disclosure [Abstract] Summary of Income Tax Contingencies [Table Text Block] Summary of Income Tax Contingencies [Table Text Block] Income Tax Expense [Table Text Block] Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Reconciliation of Expected Federal Income Tax Expense to Actual [Table Text Block] Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Tax Assets and Liabilities [Table Text Block] Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Multi-employer Plan [Abstract] Multi-employer Plan [Abstract] Schedule of Multiemployer Plans [Table] Schedule of Multiemployer Plans [Table] Multiemployer Plan Type [Axis] Multiemployer Plan Type [Axis] Multiemployer Plans Type [Domain] Multiemployer Plans Type [Domain] Multiemployer Plans, Pension [Member] Multiemployer Plans, Pension [Member] Multiemployer Plan Name [Axis] Multiemployer Plan Name [Axis] Multiemployer Plan Name [Domain] Multiemployer Plan Name [Domain] Central Pension Fund [Member] CentralPensionFund [Member] Central Pension Fund Indiana Laborers Pension Fund [Member] IndianaLaborersPensionFund [Member] Indiana Laborers Pension Fund Pipeline Industry Benefit Fund [Member] Pipeline Industry Benefit Fund [Member] Pipeline Industry Benefit Fund [Member] Laborers District Fund of Ohio [Member] Laborers District Fund of Ohio [Member] Laborers District Fund of Ohio [Member] Ohio Operating Engineers Pension Fund [Member] Ohio Operating Engineers Pension Fund [Member] Ohio Operating Engineers Pension Fund [Member] Operating Eng. Local 324 Fund [Member] Operating Eng. Local 324 Fund [Member] Operating Eng. Local 324 Fund [Member] Minnesota Laborers Pension Fund [Member] Minnesota Laborers Pension Fund [Member] Minnesota Laborers Pension Fund [Member] Laborers' Combined Fund of Western Pennsylvania [Member] Laborers' Combined Fund of Western Pennsylvania [Member] Laborers' Combined Fund of Western Pennsylvania [Member] Other Pension Funds [Member] Other Pension Funds [Member] Other Pension Funds [Member] Multiemployer Plan, Plan Information [Axis] Multiemployer Plan, Plan Information [Axis] Multiemployer Plan, Plan Information [Domain] Multiemployer Plan, Plan Information [Domain] Multiemployer Plans [Line Items] Multiemployer Plans [Line Items] Multiemployer Plan, Contributions by Employer Multiemployer Plan, Contributions by Employer Approximate number of unions the Company contributed to on behalf of employees Approximate number of unions the Company contributed to on behalf of employees The approximate number of unions the Company contributed to during the year on behalf of employees Multiemployer Plans Average Contributions Multiemployer Plans Average Contributions The average contribution made by the Company to unions within multiemployer plans during the period. Multiemployer Plans Largest Contribution Multiemployer Plans Largest Contribution The largest contribution made by the Company to a single union multiemployer plan during the period. Number of multiemployer plans contributed to Number of multiemployer plans contributed to Number of multi-employer plans contributed to Defined benefit plan, number of significant plans Defined benefit plan, number of significant plans Defined benefit plan, number of significant plans Multiemployer Plans, Certified Zone Status [Fixed List] Multiemployer Plans, Certified Zone Status [Fixed List] Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan [Fixed List] Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan [Fixed List] Multiemployer Plans, Surcharge [Fixed List] Multiemployer Plans, Surcharge [Fixed List] Defined benefit plan, number of plans in red zone status receiving company contributions Defined benefit plan, number of plans in red zone status receiving company contributions Defined benefit plan, number of plans in red zone status receiving company contributions Defined benefit plan, number of plans whereby company contributions exceed 5% of plan balance Defined benefit plan, number of plans whereby company contributions exceed 5% of plan balance Number of plans whereby company contributions exceed 5% of plan balance Defined benefit plan, percentage threshold by which plan contributions are considered significant Defined benefit plan, percentage threshold by which plan contributions are considered significant Percentage threshold in which plan contributions are considered significant Number of plans in red zone status considered significant by the Company Number of plans in red zone status considered significant by the Company Number of plans in red zone status considered significant by the Company Operating income (loss) Income (loss) available to common shareholders Basic earnings per common share (1) Diluted earnings per common share (1) Income (loss) from continuing operations Income (loss) from discontinued operations, net of tax Property, Plant and Equipment [Text Block] Property, Plant and Equipment Disclosure [Text Block] Dividends Declared [Table Text Block] Dividends Declared [Table Text Block] Convertible Debt [Table Text Block] Convertible Debt [Table Text Block] Goodwill by Reportable Segments [Table Text Block] Schedule of Goodwill [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Finite-Lived Intangible Assets [Table Text Block] Finite-lived Intangible Assets Amortization Expense [Table Text Block] Finite-lived Intangible Assets Amortization Expense [Table Text Block] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Summary of Accounting Policies [Table] Summary of Accounting Policies [Table] Summary of Accounting Policies [Table] Interest Expense [Member] Interest Expense [Member] Other Income (Expense) [Member] Other Income [Member] Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Capitalized Fees Not Eliminated in Consolidation Capitalized Fees Not Eliminated in Consolidation Represents fees incurred from intersegment business and capitalized. Transactions are not eliminated in consolidation when capitalized and included in rate base. Interest and AFUDC debt (1) Interest Costs Capitalized Adjustment AFUDC equity (2) Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Provision for doubtful accounts Provision for Doubtful Accounts Securities Related to ZENS Debt Securities, Trading, and Equity Securities, FV-NI [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Subordinated Debt ZENS Member 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. Securities Related to ZENS Financial Instrument [Axis] Subsidiary of CenterPoint Energy equity holdings [Domain] Financial Instruments [Domain] AT&T Common [Member] AT&T Common [Member] Common stock of AT&T Inc. Charter Common [Member] Charter Common [Member] Charter Common [Member] ZENS-Related Securities [Member] TW Securities [Member] Represents collectively TW Common, TWC Common, AOL Common and Time Common securities related to ZENS. Debt Component Of ZENS [Member] Debt Component Of ZENS [Member] Represents the bifurcated fixed rate debt component of the ZENS obligation Derivative Component Of ZENS [Member] Derivative Component Of ZENS [Member] Represents the bifurcated derivative component of the ZENS obligation Indexed Debt Securities [Line Items] Debt and Equity Securities, FV-NI [Line Items] Balance of investment owned (in shares) Investment Owned, Balance, Shares Principal amount of debt issued Debt Instrument, Face Amount Outstanding debt balance Long-term Debt, Gross 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. 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. ZENS annual interest rate Debt Instrument, Interest Rate, Stated Percentage Target annual yield on referenced shares before increase or decrease of principal amount of subordinated note Target Annual Yield On Referenced Shares Before Increase Or Decrease Of Principal Amount Of Subordinated Note The target annual yield from interest and cash dividends on referenced shares, before any adjustment to increase or decrease principal amount of subordinated note is made. 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. 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. 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 ZENS-Related Securities Tw Securities [ Abstract] ZENS-Related Securities Proceeds from sale and maturity of marketable securities Proceeds from Sale and Maturity of Marketable Securities Gain (loss) on ZENS-Related Securities ZENS-Related Securities Debt component of ZENS Debt Component Of Zens Abstract Debt Component of ZENS 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. 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. 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. Debt Component of ZENS Derivative component of ZENS Derivative Component Of Zens Abstract Derivative Component of ZENS Loss (gain) on indexed debt securities Derivative Component of ZENS Statement of Cash Flows [Abstract] Cash Flows from Operating Activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] 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] Amortization of deferred financing costs Amortization of Debt Issuance Costs Deferred income taxes Deferred Income Tax Expense (Benefit) Unrealized loss (gain) on marketable securities Marketable Securities, Unrealized Gain (Loss), Excluding Other-than-temporary Impairment Loss 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. Write-down of natural gas inventory Inventory Write-down Income (Loss) from Equity Method Investments Proceeds from Equity Method Investment, Distribution Pension contributions Payment for Pension Benefits Changes in other assets and liabilities, excluding acquisitions: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable and unbilled revenues, net Increase (Decrease) in Accounts and Other Receivables 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. Inventory Increase (Decrease) in Inventories Taxes receivable Increase (Decrease) in Income Taxes Receivable Accounts payable Increase (Decrease) in Accounts Payable Fuel cost recovery Increase (Decrease) in over (under) Energy Recovery Non-trading derivatives, net Increase (Decrease) in Derivative Assets and Liabilities Margin deposits, net Increase (Decrease) in Margin Deposits Outstanding Interest and taxes accrued Increase Decrease Interest and taxes accrued Increase (decrease) in interest and taxes accrued. Net regulatory assets and liabilities Increase (Decrease) in Regulatory Assets and Liabilities Other current assets Increase (Decrease) in Other Current Assets Other current liabilities Increase (Decrease) in Other Current Liabilities Other assets Increase (Decrease) in Other Noncurrent Assets Other liabilities Increase (Decrease) in Other Noncurrent Liabilities Other, net Other Operating Activities, Cash Flow Statement Net cash provided by operating activities from continuing operations Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash provided by operating activities from discontinued operations Cash Provided by (Used in) Operating Activities, Discontinued Operations Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash Flows from Investing Activities: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Capital expenditures Payments to Acquire Productive Assets Acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired (Increase) decrease in notes receivable–affiliated companies Increase (Decrease) in Notes Receivable, Related Parties Distributions from unconsolidated affiliates in excess of cumulative earnings Proceeds from Equity Method Investment, Distribution, Return of Capital Proceeds from sale of marketable securities Proceeds from sale of assets Proceeds from Sale of Property, Plant, and Equipment Purchase of investments Payments to Acquire Investments Other, net Payments for (Proceeds from) Other Investing Activities Net cash used in investing activities from continuing operations Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash provided by investing activities from discontinued operations Cash Provided by (Used in) Investing Activities, Discontinued Operations Net cash provided by (used in) investing activities Net Cash Provided by (Used in) Investing Activities Cash Flows from Financing Activities: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Increase (decrease) in short-term borrowings, net Proceeds from (Repayments of) Short-term Debt Proceeds from (payments of) commercial paper, net Proceeds from (Repayments of) Commercial Paper Proceeds from long-term debt, net Proceeds from Issuance of Long-term Debt Payments of long-term debt Repayments of Long-term Debt Dividend to parent Increase (decrease) in notes payable–affiliated companies Increase (Decrease) in Notes Payable, Related Parties Loss on reacquired debt Payment for Debt Extinguishment or Debt Prepayment Cost Debt and equity issuance costs Payment of Financing and Stock Issuance Costs Debt issuance costs Payments of Debt Issuance Costs Contribution from parent Proceeds from Contributions from Parent Payment of dividends on Common Stock Payments of Ordinary Dividends, Common Stock Payment of dividends on preferred stock Payments of Ordinary Dividends, Preferred Stock and Preference Stock Proceeds from issuance of Common Stock, net Proceeds from Issuance of Common Stock Proceeds from issuance of preferred stock, net Proceeds from Issuance of Preferred Stock and Preference Stock Other, net Proceeds from (Payments for) Other Financing Activities Net cash used in financing activities from continuing operations Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net cash provided by financing activities from discontinued operations Cash Provided by (Used in) Financing Activities, Discontinued Operations Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities 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 Cash, Cash Equivalents and Restricted Cash at Beginning of Year Cash, Cash Equivalents and Restricted Cash at End of Year 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. Cumulative preferred stock par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Cumulative preferred stock shares authorized (in shares) Preferred Stock, Shares Authorized Common stock shares par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock shares authorized (in shares) Common Stock, Shares Authorized Partner Type [Axis] Partner Type [Axis] Partner Type of Partners' Capital Account, Name [Domain] Partner Type of Partners' Capital Account, Name [Domain] Enable GP, LLC [Member] Enable GP, LLC [Member] Enable GP, LLC [Member] Preferred Units by Name [Axis] Series A Preferred Units [Member] Cash paid to acquire Vectren Payments to Acquire Businesses, Gross Number of states in which entity operates Number of States in which Entity Operates Ownership percentage of equity method investment Equity Method Investment, Ownership Percentage Management rights ownership percentage Management Rights Ownership Percentage Represents the percentage of management rights in the general partner of Enable Incentive distribution right Incentive Distribution Right, Percentage Entity's interest in incentive distribution rights held by the general partner. Preferred units held Preferred Units Held Represents the number of Series A Preferred Units held as of the balance sheet date. Cover page. Entities [Table] Entities [Table] CenterPoint Energy Houston Electric, LLC CenterPoint Energy Resources Corp. Common Stock, $0.01 par value Common Stock, $0.01 Par Value [Member] Common Stock, $0.01 Par Value [Member] 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] 9.15% First Mortgage Bonds due 2021 9.15% First Mortgage Bonds Due 2021 [Member] 9.15% First Mortgage Bonds Due 2021 [Member] 6.95% General Mortgage Bonds due 2033 6.95% General Mortgage Bonds Due 2033 [Member] 6.95% General Mortgage Bonds Due 2033 [Member] 6.625% Senior Notes due 2037 6.625% Senior Notes Due 2037 [Member] 6.625% Senior Notes Due 2037 [Member] Entity Listings, Exchange [Axis] Entity Listings, Exchange [Axis] Exchange [Domain] Exchange [Domain] New York Stock Exchange New York Stock Exchange [Member] New York Stock Exchange [Member] Chicago Stock Exchange Chicago Stock Exchange [Member] Chicago Stock Exchange [Member] Entity Information [Line Items] Entity Information [Line Items] Document Type Document Type Document Annual Report Document Annual Report Document Transition Report Document Transition Report Entity File Number Entity File Number Entity Registrant Name Entity Registrant Name Entity Tax Identification Number Entity Tax Identification Number Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code City Area Code City Area Code Local Phone Number Local Phone Number Title of 12(b) Security Title of 12(b) Security Trading Symbol Trading Symbol Security Exchange Name Security Exchange Name Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Voluntary Filers Entity Voluntary Filers Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Filer Category Entity Filer Category Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Public Float Entity Public Float Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Income Taxes [Text Block] Income Tax Disclosure [Text Block] Merger with Vectren [Abstract] Merger with Vectren [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Tax Credit Carryforward [Axis] Tax Credit Carryforward [Axis] Tax Credit Carryforward, Name [Domain] Tax Credit Carryforward, Name [Domain] Charitable Contribution [Member] Charitable Contribution [Member] Charitable Contribution [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Operating loss carryforwards Operating Loss Carryforwards Deferred tax assets tax credit carryforwards Tax Credit Carryforward, Amount Long-term Purchase Commitment [Table] Long-term Purchase Commitment [Table] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] CES natural gas related transactions [Member] CES natural gas related transactions [Member] CES natural gas related transactions [Member] Indiana Electric [Member] Indiana Electric [Member] Operations of SIGECO 's electric transmission and distribution services , including power generation and wholesale power operations [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Minnehaha Academy Gas Explosion [Member] Damage from Fire, Explosion or Other Hazard [Member] Environmental Remediation Site [Axis] Environmental Remediation Site [Axis] Environmental Remediation Site [Domain] Environmental Remediation Site [Domain] Indiana Gas Service Territory [Member] Indiana Gas Service Territory [Member] Represents the areas in Indiana serviced by Indiana Gas Service Minnesota and Indiana Gas Service Territories [Member] Minnesota and Indiana Gas Service Territory [Member] Minnesota and Indiana Gas Service Territory [Member] Purchase Obligations Long-term Purchase Commitment [Line Items] 2020 Purchase Obligation, Due in Next Twelve Months 2021 Purchase Obligation, Due in Second Year 2022 Purchase Obligation, Due in Third Year 2023 Purchase Obligation, Due in Fourth Year 2024 Purchase Obligation, Due in Fifth Year 2025 and beyond Purchase Obligation, Due after Fifth Year Performance Guarantees & Product Warranties [Abstract] Performance Guarantees & Product Warranties [Abstract] Performance Guarantees & Product Warranties [Abstract] 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 Performance guarantee obligations outstanding face amount Performance guarantee obligations outstanding face amount Face amount of individual surety bonds the wholly-owned subsidiary has outstanding 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. Guarantor Obligations, Maximum Exposure, Undiscounted Guarantor Obligations, Maximum Exposure, Undiscounted Annualized fee received for retained CES obligation guarantees Annualized fee received for retained CES obligation guarantees Annualized fee received for retained CES obligation guarantees 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 Guarantor Obligations, Current Carrying Value Guarantor Obligations, Current Carrying Value Legal, Environmental and Other Matters Loss Contingency, Information about Litigation Matters [Abstract] Contested amount of fines imposed ContestedAmountOfFinesImposed Contested amount of fines imposed by the Minnesota Office of Pipeline Safety. 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 Liability recorded for remediation of Minnesota sites Accrual for Environmental Loss Contingencies Estimated remediation costs for the Minnesota sites Site Contingency Loss Exposure Estimate of the reasonably possible loss exposure at an individual site. Years to resolve contingency Site Contingency, Years to Resolve Contingency This represents the estimated years necessary to resolve the contingency. Asset Retirement Obligation Estimated capital expenditure to clean ash ponds Estimated capital expenditure to clean ash ponds Estimated Capital Expenditure to Clean Ash Ponds Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments [Table Text Block] Equity Method Investments [Table Text Block] Disposal Groups, Including Discontinued Operations [Table Text Block] Disposal Groups, Including Discontinued Operations [Table Text Block] Short-term Borrowings and Long-term Debt [Text Block] Debt Disclosure [Text Block] 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] Mergers and Acquisitions [Text Block] Business Combination Disclosure [Text Block] Basic and Diluted Earnings Per Share [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Short-Term Borrowings and Long-Term Debt [Table] Short-Term Borrowings and Long-Term Debt [Table] Short-Term Borrowings and Long-Term Debt [Table] Parent Company [Member] Parent Company [Member] VUHI [Member] VUHI [Member] VUHI [Member] VCC [Member] VCC [Member] Vectren Capital Corp Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Revolving Credit Facility [Member] Revolving Credit Facility [Member] Line of Credit [Member] Line of Credit [Member] Letter of Credit [Member] Letter of Credit [Member] Commercial paper (4) Commercial Paper [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] London Interbank Offered Rate (LIBOR) [Member] London Interbank Offered Rate (LIBOR) [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Legal entity [Axis] Senior Notes due 2022 [Member] Senior Notes due 2022 [Member] Senior Notes due 2022 [Member] Senior Notes due 2025 [Member] Senior Notes due 2025 [Member] Senior Notes due 2025 [Member] Variable rate term loan [Member] Variable rate term loan [Member] Variable rate term loan [Member] Variable term rate loan 2 [Member] Variable term rate loan 2 [Member] Variable term rate loan 2 [Member] Senior Notes Due 2030 [Member] Senior Notes Due 2030 [Member] Senior Notes Due 2030 [Member] Senior Notes Due 2024 [Member] Senior Notes Due 2024 [Member] Senior Notes Due 2024 [Member] Senior Notes Due 2049 [Member] Senior Notes Due 2049 [Member] Senior Notes Due 2049 [Member] General Mortgage Bonds Due 2049 [Member] General Mortgage Bonds Due 2049 [Member] General Mortgage Bonds Due 2049 [Member] Pollution control bonds 5.125% due 2028 (5) Bonds Pollution Control Due Range 1 [Member] Bonds Pollution Control Due Range 1 [Member] Senior Notes due 2022 and 2025 [Member] Senior Notes due 2022 and 2025 [Member] Senior Notes due 2022 and 2025 [Member] Securitization Bonds [Member] Transition And System Restoration Bonds [Member] Represents the amount of transition and system restoration bonds maturing. 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. 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] Long term Debt Excluding ZENS [Member] Long term Debt Excluding ZENS [Member] Represents balances related to long-term debt excluding ZENS Debt Instrument [Line Items] Debt Instrument [Line Items] Long-term debt: Long-term Debt, by Current and Noncurrent [Abstract] Amount of debt retired Extinguishment of Debt, Amount Debt instrument interest rate Line of Credit Facility [Abstract] Line of Credit Facility [Abstract] Size of credit facility Line of Credit Facility, Maximum Borrowing Capacity Long-term line of credit Maximum number of days until maturity of commercial paper issued in connection with the Merger Maximum number of days until maturity of commercial paper issued in connection with the Merger. Weighted average interest rate of commercial paper issued in connection with the Merger Weighted average interest rate of commercial paper issued in connection with the Merger Weighted average interest rate of commercial paper issued in connection with the Merger. Basis spread on LIBOR Debt Instrument, Basis Spread on Variable 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. Ratio of indebtedness to net capital Ratio of Indebtedness to Net Capital 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) 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 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) Annual maturities of long term debt, capital leases, and sinking fund requirements, excluding ZENS obligations [Abstract] Long-term Debt, Fiscal Year Maturity [Abstract] 2020 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2021 Long-term Debt, Maturities, Repayments of Principal in Year Two 2022 Long-term Debt, Maturities, Repayments of Principal in Year Three 2023 Long-term Debt, Maturities, Repayments of Principal in Year Four 2024 Long-term Debt, Maturities, Repayments of Principal in Year Five Secured debt amount with asset liens Secured Debt 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. 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. 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. Long-term Line of Credit Long-term Line of Credit Debt, Weighted Average Interest Rate Debt, Weighted Average Interest Rate 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. Percentage of property additions Percentage of property additions Percentage of property additions Credit facility swing line sublimit Credit facility swing line sublimit Credit facility swing line sublimit. Letters of credit swing line sublimit Letters of credit swing line sublimit Letters of credit swing line sublimit Number of days until commercial paper maturity Number of days until commercial paper maturity Number of days until commercial paper maturity. Make-whole premium Make-whole premium Make-whole premium Not Designated as Hedging Instrument, Economic Hedge [Member] Not Designated as Hedging Instrument, Economic Hedge [Member] Weather Hedge Term [Axis] Weather Hedge Term [Axis] Represents the term of the weather hedges Weather Hedge Term [Domain] Weather Hedge Term [Domain] [Domain] for Represents the term of the weather hedges 2019 to 2020 [Member] 2019 to 2020 [Member] 2019 to 2020 [Member] 2018 to 2019 [Member] 2018 to 2019 [Member] 2018 to 2019 [Member] 2017 to 2018 [Member] 2017to2018 [Member] 2017to2018 [Member] 2016 to 2017 [Member] 2016to2017 [Member] 2016to2017 [Member] Weather Hedge Swaps [Member] Weather Hedge Swaps [Member] Heating-degree day swaps to mitigate the effect of fluctuations from normal weather for the winter heating season. Derivative Liability, Notional Amount Derivative Liability, Notional Amount Weather hedges term Weather Hedges Term Period of time used as the basis for weather hedges entered into by the company. Weather hedge bilateral cap amount Weather Hedge, Bilateral Cap Amount Represents amount of bilateral cap related to weather hedges. Recognized gain (loss) on weather hedges Derivative, Gain (Loss) on Derivative, Net Adoption of ASU 2018-02 [Member] Accounting Standards Update 2018-02 [Member] Accounting Standards Update 2018-02 Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income Pension and Other Postretirement Plans [Member] Other Pension, Postretirement and Supplemental Plans [Member] Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] Over-Allotment Option [Member] Over-Allotment Option [Member] Preferred Stock, Redemption, Period [Axis] Preferred Stock, Redemption, Period [Axis] Preferred Stock, Redemption, Period [Axis] Preferred Stock, Redemption, Period [Domain] Preferred Stock, Redemption, Period [Domain] [Domain] for Preferred Stock, Redemption, Period [Axis] 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] Series B [Member] Series B [Member] Depositary Share [Member] Depositary Share [Member] Each depositary Share represents 1/20th share of Series B Preferred Stock. Dividends declared per share Dividends declared per share Dividends declared Dividends, Common Stock, Cash Dividends declared Stock issued (in shares) Preferred stock par value (in dollars per share) Proceeds from the issuance of Series A Preferred Stock, net Preferred stock liquidation preference Preferred Stock, Liquidation Preference, Value Preferred stock liquidation preference (per share) Preferred Stock, Liquidation Preference Per Share Preferred stock dividend rate Preferred Stock, Dividend Rate, Percentage Preferred stock redemption price (per share) Preferred Stock, Redemption Price Per Share 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. 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. Proceeds from the issuance of Series B Preferred Stock, net Proceeds from Issuance of Convertible Preferred Stock Depositary Share, Conversion Ratio Depositary Share, Conversion Ratio Represents the ratio of interest of one depositary share in a share of Series B Preferred Stock 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. Conversion rate per share Convertible Preferred Stock, Shares Issued upon Conversion Preferred Stock, Convertible, Conversion Price Preferred Stock, Convertible, Conversion Price The price per share of the conversion feature embedded in the preferred stock. Depositary share par value (in dollars per depositary share) Sale of Stock, Price Per Share Number of depositary shares eligible for conversion (in shares) Conversion of Stock, Shares Converted Preferred stock threshold consecutive calendar days Preferred Stock, Convertible, Threshold Consecutive Calendar Days Threshold period of consecutive calendar days for fundamental change conversion. Common stock issued per share price Shares Issued, Price Per Share Proceeds from issuance of common stock Undistributed earnings from equity method investments included in retained earnings Retained Earnings, Undistributed Earnings from Equity Method Investees Gain (loss) reclassified from accumulated OCI into income Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Accumulated Other Comprehensive Income (Loss) [Roll Forward] Accumulated Other Comprehensive Income (Loss) [Roll Forward] Accumulated Other Comprehensive Income (Loss) [Roll Forward] Beginning Balance Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax Other comprehensive income (loss) before reclassifications: Other Comprehensive Income (Loss), before Reclassifications, before Tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Prior service cost (2) Actuarial losses (2) Tax benefit (expense) Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Net current period other comprehensive income (loss) Adoption of ASU 2018-02 New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification Ending Balance 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] Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs [Table Text Block] Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Estimated Fair Value of Financial Instruments, Debt Instruments [Table Text Block] Fair Value, by Balance Sheet Grouping [Table Text Block] Statement of Comprehensive Income [Abstract] Tax benefit (expense) on adjustment related to pension and postretirement plans Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Attributable to Parent Tax expense (benefit) on net deferred gain (loss) from cash flow hedges Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax Tax expense (benefit) on deferred loss from cash flow hedges realized in net income Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Supplemental Disclosure of Cash Flow Information [Text Block] Cash Flow, Supplemental Disclosures [Text Block] Unconsolidated Affiliate (CenterPoint Energy and CERC) [Text Block] Equity Method Investments and Joint Ventures Disclosure [Text Block] Fair Value Measurements [Text Block] Fair Value Disclosures [Text Block] Indiana Gas [Member] Indiana Gas [Member] Indiana Gas [Member] ZENS due 2029 (2) Senior notes 2.50% to 7.08% due 2020 to 2049 (3) Senior Notes Due Range 1 [Member] Senior Notes Due Range 1 [Member] First Mortgage Bonds [Member] First Mortgage Bonds [Member] First Mortgage Bonds [Member] System restoration bonds 4.243% due 2022 Bonds System Restoration Due Range 1 [Member] Bonds System Restoration Due Range 1 [Member] Transition bonds 5.302% due 2019 Bonds Transition Due Range 2 [Member] Bonds Transition Due Range 2 [Member] Transition bonds 5.234% due 2020 Bonds Transition Due Range 1 Member [Member] Bonds Transition Due Range 1 Member [Member] Transition bonds 2.161% to 3.028% due 2020 to 2024 Bonds Transition Due Range 3 [Member] Bonds Transition Due Range 3 [Member] Senior notes 3.55% to 6.625% due 2021 to 2047 Senior Notes Due Range 2 [Member] Senior Notes Due Range 2 [Member] Other Debt Obligations [Member] Other Debt Obligations [Member] Short term borrowings: Short term debt [Abstract] Short term debt [Abstract] 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. Unamortized Issuance Costs Debt Issuance Costs, Noncurrent, Net Unamortized Discount (Premium), Net Debt Instrument, Unamortized Discount (Premium), Net Long-term Debt Long-term Debt Debt, Current Debt, Current Notes Payable, Related Parties, Noncurrent Notes Payable, Related Parties, Noncurrent Interest Expense, Related Party Interest Expense, Related Party Commercial paper issued in connection with the Merger Commercial paper issued in connection with the Merger Amount of commercial paper issued to fund a portion of the Merger and various other Merger-related costs. Amount of debt secured by general mortgage bonds Related Party Transactions (Houston Electric and CERC) [Text Block] Related Party Transactions Disclosure [Text Block] Summary of Significant Accounting Policies [Text Block] Significant Accounting Policies [Text Block] 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. Schedule of Related Party Transactions [Table Text Block] Schedule of Related Party Transactions [Table Text Block] Award Type [Axis] Restricted Stock [Member] Restricted Stock [Member] Numerator: Earnings Per Share, Basic and Diluted [Abstract] Income available to common shareholders - basic (1) Add back: Series B Preferred Stock dividend Income available to common shareholders - diluted (1) Net Income (Loss) Available to Common Stockholders, Diluted Denominator: Weighted Average Number of Shares Outstanding Reconciliation [Abstract] Weighted average common shares outstanding - basic Plus: Incremental shares from assumed conversions: Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Restricted stock (3) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Series B Preferred Stock (2) Incremental Common Shares Attributable to Dilutive Effect of Conversion of Preferred Stock Weighted average common shares outstanding - diluted Reduction in income taxes due to tax reform 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. Preferred Stock Dividends, Income Statement Impact Amount of antidilutive securities excluded from computation of earnings per share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Cumulative Preferred Stock [Member] Cumulative Preferred Stock [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Primary Beneficiary [Member] Variable Interest Entity, Primary Beneficiary [Member] Cash and cash equivalents Bad debt reserve Allowance for Doubtful Accounts Receivable, Current Accounts receivable Preferred Stock, Liquidation Preference, Value Cumulative preferred stock authorized (in shares) Cumulative preferred stock outstanding (in shares) Common stock par value (in dollars per share) Common stock authorized (in shares) Common stock outstanding (in shares) Schedule of Segment Reporting [Table] Schedule of Segment Reporting Information, by Segment [Table] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Discontinued Operations, Disposed of by Means Other than Sale, Spinoff [Member] Discontinued Operations, Disposed of by Means Other than Sale, Spinoff [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] Operating Segments [Member] Operating Segments [Member] Segment Reconciling Items [Member] Segment Reconciling Items [Member] Midstream Investments [Member] Midstream Investments [Member] Midstream Investments [Member] Major Customers [Axis] Customer [Axis] Name of Major Customer [Domain] Customer [Domain] Affiliates of NRG Energy, Inc. [Member] Affiliates of NRG Energy, Inc. [Member] Affiliates of NRG Energy, Inc. [Member] Affiliates of Vistra Energy Corp. [Member] Affiliates of Vistra Energy Corp. [Member] Affiliates of Vistra Energy Corp. [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Depreciation and Amortization Operating Income (Loss) Total Assets Investment in unconsolidated affiliates - discontinued operations Disposal Group, Including Discontinued Operation, Assets Expenditures for Long-Lived Assets Capital Expenditures for Long-Lived Assets Capital Expenditures for Long-Lived Assets Capital expenditures per Statements of Consolidated Cash Flows Midstream Investments’ equity earnings, net Short-term Investments Regulatory Assets Nature of Expense [Axis] Nature of Expense [Axis] Interim Period, Costs Not Allocable [Domain] Interim Period, Costs Not Allocable [Domain] Transitional Service [Member] Transitional Service [Member] Transitional services costs, including the costs of seconded employees. Common Units [Member] Series A Preferred Units [Member] Non-utility Investments [Member] Non-utility Investments [Member] Non-utility Investments [Member] Proliance Holdings LLC [Member] Proliance Holdings LLC [Member] Proliance Holdings LLC [Member] OGE [Member] OGE [Member] OGE [Member] Public unitholders [Member] Public unitholders [Member] Public unitholders [Member] Series A Preferred Units [Member] Equity Method Investment Decrease in Carrying Value Equity Method Investment Decrease in Carrying Value Represents the amount below carrying value of an equity method investment as of a specified time. 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. Share Price Share Price Enable Equity Summary [Abstract] Enable Equity Summary [Abstract] Enable Equity Summary [Abstract] Enable Partnership Interest [Abstract] Limited Partner Interest in Enable [Abstract] Limited Partner Interest in Enable [Abstract] Limited partner ownership interest Limited partner ownership interest Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Enable Units [Abstract] Enable common units and Series A Preferred Units Held [Abstract] Enable common units and Series A Preferred Units Held [Abstract] Limited partner interest units held Equity Method Investment, Ownership, Shares Equity Method Investment, Ownership, Shares 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 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. Incentive distribution per unit Incentive Distribution, Distribution Per Unit Maximum incentive distribution right Incentive Distribution Right, Maximum Maximum additional incentive right to the general partner with quarterly distribution per unit exceeding $0.330625 Enable Distributions [Abstract] Enable Distributions [Abstract] Enable Distributions [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. 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. Distributions received from Enable cost method investment 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. Transaction with Enable [Abstract] Transaction with Enable [Abstract] Transaction with Enable [Abstract] Natural gas expenses, including transportation and storage costs (1) Related Party Transaction, Purchases from Related Party Reimbursement of support services (2) Related Party Transaction, Other Revenues from Transactions with Related Party Accounts payable for natural gas purchases from Enable Accounts Payable, Related Parties, Current Accounts receivable for amounts billed for services provided to Enable Accounts Receivable, Related Parties Equity Method Investment, Summarized Financial Information, Income Statement [Abstract] Equity Method Investment, Summarized Financial Information, Income Statement [Abstract] Operating revenues Equity Method Investment, Summarized Financial Information, Revenue Cost of sales, excluding depreciation and amortization Equity Method Investment, Summarized Financial Information, Cost of Sales 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. 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. Net income attributable to Enable common units Equity Method Investment, Summarized Financial Information, Net Income (Loss) 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. Basis difference amortization (1) Basis Difference Accretion Gain Basis Difference Accretion Gain Loss on dilution, net of proportional basis difference recognition Equity Method Investment, Other than Temporary Impairment CenterPoint Energy’s equity in earnings, net Equity Method Investment, Summarized Financial Information [Abstract] Equity Method Investment, Summarized Financial Information [Abstract] Current assets Equity Method Investment, Summarized Financial Information, Current Assets Non-current assets Equity Method Investment, Summarized Financial Information, Noncurrent Assets Current liabilities Equity Method Investment, Summarized Financial Information, Current Liabilities Non-current liabilities Equity Method Investment, Summarized Financial Information, Noncurrent Liabilities Non-controlling interest Equity Method Investment, Summarized Financial Information, Noncontrolling Interest Preferred equity Equity Method Investment, Summarized Financial Information, Preferred Equity Amount of preferred equity attributable to the equity method investment of the entity. Equity Method Investment Summarized Financial Information Accumulated Other Comprehensive Income Loss Equity Method Investment Summarized Financial Information Accumulated Other Comprehensive Income Loss EquityMethodInvestmentSummarizedFinancialInformationAccumulatedOtherComprehensiveIncomeLoss Enable partners’ equity Equity Method Investment, Summarized Financial Information, Equity Excluding Noncontrolling Interests Equity Method Investment, Difference Between Carrying Amount and Underlying Equity [Abstract] Equity Method Investment, Difference Between Carrying Amount and Underlying Equity [Abstract] CenterPoint Energy’s ownership interest in Enable partners’ equity Equity Method Investment, Underlying Equity in Net Assets CenterPoint Energy’s basis difference Equity Method Investment, Basis Difference This represents the basis difference of an equity method investment. CenterPoint Energy’s equity method investment in Enable Discontinued Operation, Income (Loss) from Discontinued Operation Disclosures [Abstract] Discontinued Operation, Income (Loss) from Discontinued Operation Disclosures [Abstract] Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax Income tax expense Schedule of Property, Plant and Equipment [Table Text Block] Property, Plant and Equipment [Table Text Block] 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. Asset Retirement Obligation [Table Text Block] Schedule of Change in Asset Retirement Obligation [Table Text Block] Pro Forma [Member] Pro Forma [Member] Utility pipeline construction company [Member] Utility pipeline construction company [Member] Utility pipeline construction company [Member] Period [Axis] Period [Axis] Period of the transaction occurred [Axis] Period [Domain] Period [Domain] [Domain] for Period of the transaction occurred [Axis] Stub period [Member] Stub period [Member] Stub period [Member] Construction backlog [Member] Customer Contracts [Member] Operation and maintenance agreements and construction backlog [Member] Operation and maintenance agreements and construction backlog [Member] Operation and maintenance agreements and construction backlog [Member] Customer relationships and trade names [Member] Customer relationships and trade names [Member] Customer relationships and trade names [Member] Business Combinations [Line Items] Total purchase price consideration Cash paid per share of Vectren common stock at closing of the Merger Business Acquisition, Share Price 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. Share-based award liability recorded Deferred Compensation Liability, Classified, Noncurrent Incremental share-based awards expense recorded Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation Cost Severance expense related to the Merger Severance Costs Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract] Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract] Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Other current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets Property, plant and equipment, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Identifiable intangibles Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Regulatory assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Assets Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Total assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Current liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities Regulatory liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities Other liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Long-term debt Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-term Debt Total liabilities assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Net assets acquired Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill [Abstract] Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill [Abstract] Weighted Average Useful Lives Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Estimated Fair Value Finite-lived Intangible Assets Acquired Amortization expense of intangible assets Business Combination, Separately recognized Transactions, Additional Disclosures [Abstract] Business Combination, Separately recognized Transactions, Additional Disclosures [Abstract] Integration costs Business Combination, Integration Related Costs Business Acquisition, Pro Forma Information [Abstract] Business Acquisition, Pro Forma Information [Abstract] Operating Revenue Business Acquisition, Pro Forma Revenue Net Income (1) Business Acquisition, Pro Forma Net Income (Loss) 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. Benefit Obligation [Member] Benefit Obligation [Member] Represents the benefit obligation on the balance sheet. Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] U.S. Equity [Member] U.S. Equity [Member] U.S. Equity [Member] International Developed Market Equity [Member] International Developed Market Equity [Member] International Developed Market Equity [Member] Real Estate Funds [Member] Real Estate Funds [Member] Fixed Income [Member] Fixed Income [Member] Fixed Income [Member] 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. Cash received as collateral from securities [Member] Cash Received As Collateral Member The fair value of cash collateral received against securities loaned to borrowers. U.S. treasuries [Member] US Treasury Securities [Member] Mortgage backed securities [Member] Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] Asset backed securities [Member] Asset-backed Securities, Securitized Loans and Receivables [Member] Municipal bonds [Member] US States and Political Subdivisions Debt Securities [Member] Mutual funds [Member] Equity Funds [Member] International government bonds [Member] Debt Security, Government, Non-US [Member] Common Collective Trust Funds [Member] Common Collective Trust Funds Member Consists of common collective trust funds invested in equities and fixed income securities. Fixed Income Funds [Member] Fixed Income Funds [Member] Fair value of plan assets measurement [Axis] Fair value of plan assets measurement [Domain] Investment Type [Axis] Investment Type [Axis] Investments [Domain] Investments [Domain] International Equity [Member] International Equity [Member] International Equity [Member] Emerging Market Equity [Member] Emerging Market Equity [Member] Emerging Market Equity [Member] Discount Rate Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Plan assets, fair value 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. 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. Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage 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. Total contributions to the plans during the period Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year Defined Benefit Plan, Estimated Future Benefit Payments [Abstract] Defined Benefit Plan, Expected Future Benefit Payment [Abstract] Pension benefit payments 2020 Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months Pension benefit payments 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year Two Pension benefit payments 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Three Pension benefit payments 2023 Defined Benefit Plan, Expected Future Benefit Payment, Year Four Pension benefit payments 2024 Defined Benefit Plan, Expected Future Benefit Payment, Year Five Pension benefit payments 2025 - 2029 Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter Savings Plan [Abstract] Savings Plan Abstract 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 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. 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. Defined Contribution Plan, Cost Defined Contribution Plan, Cost Postemployment Benefits [Abstract] Postemployment Benefits [Abstract] Postemployment Benefits, Period Expense Postemployment Benefits, Period Expense Postemployment benefit obligations Postemployment Benefits Liability, Noncurrent Other Non-Qualified Plans [Abstract] Other Nonqualified Plan Abstract Benefit expense related to deferred compensation plans Deferred Compensation Arrangement with Individual, Compensation Expense Other non-qualified plans benefit obligations deferred compensation 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. Commitments and Contingencies [Text Block] Commitments and Contingencies Disclosure [Text Block] Schedule of Subsequent Events [Table Text Block] Schedule of Subsequent Events [Table Text Block] Contract Balances [Table] Contract Balances [Table] Contract Balances [Table] Contract Balances [Line Items] Contract Balances [Line Items] [Line Items] for Contract Balances [Table] Change in Accounts Receivable [Roll Forward] Change in Accounts Receivable [Roll Forward] Change in Accounts Receivable [Roll Forward] Opening balance as of December 31, 2018 (1) Accounts Receivable for Contracts with Customers Accounts Receivable for Contracts with Customers Closing balance as of December 31, 2019 Increase (Decrease) in Accounts Receivable Increase (Decrease) in Accounts Receivable on Contracts with Customers Increase (Decrease) in Accounts Receivable on Contracts with Customers Change in Other Accrued Unbilled Revenues [Roll Forward] Change in Other Accrued Unbilled Revenues [Roll Forward] Change in Other Accrued Unbilled Revenues [Roll Forward] Opening balance as of December 31, 2018 (1) Unbilled Contracts Receivable Closing balance as of December 31, 2019 Increase (Decrease) in Other Accrued Unbilled Revenues Increase (Decrease) in Unbilled Receivables Change in Contract Asset [Roll Forward] Change in Contract Asset [Roll Forward] Change in Contract Asset [Roll Forward] Opening balance as of December 31, 2018 (1) Contract with Customer, Asset, Net, Current Closing balance as of December 31, 2019 Increase (Decrease) in Contract with Customer, Asset Increase (Decrease) in Contract with Customer, Asset Change in Contract Liability [Roll Forward] Change in Contract Liability [Roll Forward] Change in Contract Liability [Roll Forward] Opening balance as of December 31, 2018 (1) Contract with Customer, Liability Closing balance as of December 31, 2019 Increase (Decrease) in Contract with Customer, Liability Increase (Decrease) in Contract with Customer, Liability Contract with Customer, Liability, Revenue Recognized Contract with Customer, Liability, Revenue Recognized Other Tax Carryforward [Table] Tax Credit Carryforward [Table] Effective Income Tax Rate Reconciliation, Other Adjustments [Axis] Effective Income Tax Rate Reconciliation, Other Adjustments [Axis] Effective Income Tax Rate Reconciliation, Other Adjustments [Axis] 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] 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] Tax Basis Balance Sheet Adjustment [Member] Tax Basis Balance Sheet Adjustment [Member] Tax Basis Balance Sheet Adjustment [Member] Operating Activities [Axis] Operating Activities [Axis] Operating Activities [Domain] Operating Activities [Domain] Continuing Operations [Member] Continuing Operations [Member] Discontinued Operations [Member] Discontinued Operations [Member] Change in Corporate Federal Income Tax Rate under TCJA [Axis] Change in Corporate Federal Income Tax Rate under TCJA [Axis] Change in Corporate Federal Income Tax Rate under TCJA [Axis] Change in Corporate Federal Income Tax Rate under TCJA [Domain] Change in Corporate Federal Income Tax Rate under TCJA [Domain] [Domain] for Change in Corporate Federal Income Tax Rate under TCJA [Axis] Federal Income Tax Rate Prior To TCJA [Member] Federal Income Tax Rate Prior To TCJA [Member] The federal statutory income tax rate prior to the enactment of The Tax Cuts and Jobs Act of 2017. Federal Income Tax Rate After TCJA [Member] Federal Income Tax Rate After TCJA [Member] The federal statutory income tax rate after the enactment of The Tax Cuts and Jobs Act of 2017. Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] State and Local Jurisdiction [Member] State and Local Jurisdiction [Member] Other Tax Carryforward [Line Items] Tax Credit Carryforward [Line Items] Current income tax expense (benefit): Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Total current expense (benefit) Current Income Tax Expense (Benefit) Deferred income tax expense (benefit): Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Total deferred expense (benefit) Total income tax expense (benefit) Income tax reconciliation [Abstract] Effective Income Tax Rate Reconciliation, Amount [Abstract] Income before income taxes Income before income taxes Federal statutory income tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Expected federal income tax expense Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount Increase (decrease) in tax expense resulting from: Change In Tax Expense Abstract State income tax expense, net of federal income tax Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount State valuation allowance, net of federal income tax Effective Income Tax Rate Reconciliation, Other Adjustments, Amount State law change, net of federal income tax Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Federal income tax rate reduction Goodwill impairment Effective Income Tax Rate Reconciliation, Deduction, Other, Amount Excess deferred income tax amortization Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amortization, Amount Other, net Effective Income Tax Rate Reconciliation, Other Reconciling Items, Amount Total Income Tax Reconciliation Change In Tax Expense Represents the increase (decrease) in tax expense resulting from various reconciling items. Effective tax rate (in hundredths) Effective Income Tax Rate Reconciliation, Percent Deferred tax assets: Deferred Tax Assets, Net [Abstract] Benefits and compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits Regulatory liabilities Deferred Tax Assets, Regulatory Assets and Liabilities Loss and credit carryforwards Deferred Tax Assets, Other Tax Carryforwards Asset retirement obligations Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Asset Retirement Obligations Deferred Tax Assets, Derivative Instruments Deferred Tax Assets, Derivative Instruments 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. Valuation allowance Deferred Tax Assets, Valuation Allowance Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Deferred tax liabilities: Deferred Tax Liabilities, Gross [Abstract] Property, plant, and equipment Deferred Tax Liabilities, Property, Plant and Equipment Investment in unconsolidated affiliates Deferred Tax Liabilities, Investment in Noncontrolled Affiliates Regulatory assets Deferred Tax Liabilities, Regulatory Assets and Liabilities Investment in marketable securities and indexed debt Deferred Tax Liabilities, Investments Indexed debt securities derivative Deferred Tax Liabilities, Derivatives 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. Total deferred tax liabilities Deferred Tax Liabilities, Gross Net deferred tax liabilities Deferred Tax Liabilities, Net Reconciliation of Unrecognized Tax Benefits, excluding interest and penalties: Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Balance, beginning of year Unrecognized Tax Benefits Unrecognized tax benefits assumed through the Merger Unrecognized Tax Benefits, Increase Resulting from Acquisition Decreases related to tax positions of prior years Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Balance, end of year Unrecognized Tax benefit, impacting ETR if recognized Unrecognized Tax benefit, impacting ETR if recognized Unrecognized Tax benefit, impacting ETR if recognized Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Unrecognized Tax Benefit, including penalties and interest Unrecognized Tax Benefit, including penalties and interest Unrecognized Tax Benefit, including penalties and interest