Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Variable Interest Entity, Primary Beneficiary [Member] Variable Interest Entity, Primary Beneficiary [Member] Statement [Line Items] Statement [Line Items] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Bad Debt Reserve Allowance for Doubtful Accounts Receivable, Current Accounts receivable, net Accounts Receivable, Net, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Regulatory assets Regulatory Assets, Noncurrent Total common stock outstanding (in shares) Common Stock, Shares, Outstanding Equity Method Investments and Joint Ventures [Abstract] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Indebtedness to CERC Corp. [Member] Indebtedness to CERC Corp. [Member] Represents the indebtedness to CERC Corp. Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Enable Midstream Partners [Member] Enable Midstream Partners [Member] Enable Midstream Partners, LP Nature of Expense [Axis] Nature of Expense [Axis] Interim Period, Costs Not Allocable [Domain] Interim Period, Costs Not Allocable [Domain] Natural Gas Expenses [Member] Natural Gas Expenses [Member] Represents natural gas expenses, including transportation and storage costs. Products and Services [Axis] Products and Services [Axis] Products and Services [Domain] Products and Services [Domain] Transitional Service [Member] Transitional Service [Member] Transitional services costs, including the costs of seconded employees. Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] 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] Common Stock [Member] Common Stock [Member] Subordinated Units [Member] Subordinated Units [Member] Subordinated Units [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. OGE [Member] OGE [Member] OGE [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Purchase of Preferred Units, Price Per Unit Purchase of Preferred Units, Number of Units Purchased Represents the number of preferred units purchased in private placement. Purchase of Preferred Units, Number of Units Purchased Preferred Units Held Represents the number of Series A Preferred Units held as of the balance sheet date. Preferred units – unconsolidated affiliate Cost Method Investments Extinguishment of Debt, Amount Extinguishment of Debt, Amount Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum Interest Income (Expense), Net Interest Income, Related Party Interest Receivable Due from Related Parties, Current Service Agreement Notice For Termination At Term End, Number of Days Service Agreement Notice For Termination At Term End, Number Of Days Represents the number of days notice required prior to the end of the extension term to terminate the Services Agreement Service Agreement, Termination With Board Approval, Number Of Days Service Agreement, Termination With Board Approval, Number Of Days Represents the number of days notice required to terminate the Services Agreement or any provision thereunder upon approval by the Enable board of directors. Reimbursement for Transitional Services Reimbursement Revenue Transitional Service cost receivable Accounts Receivable, Related Parties Cost of natural gas purchases, affiliates Affiliate Costs Due to Affiliate Accounts Payable, Related Parties, Current Equity Method Investment, Ownership Percentage Equity Method Investment, Ownership Percentage Equity Method Investment, Ownership, Shares Equity Method Investment, Ownership, Shares Equity Method Investment, Ownership, Shares 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. 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 Investment in unconsolidated affiliate Equity Method Investments Goodwill and Intangible Assets Disclosure [Abstract] Schedule of Goodwill [Table] Schedule of Goodwill [Table] Business Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] 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] 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. Corporate and Other [Member] Goodwill [Line Items] Goodwill [Line Items] Goodwill, Impaired, Accumulated Impairment Loss Goodwill, Impaired, Accumulated Impairment Loss Goodwill Goodwill Document and Entity Supplemental Information [Abstract] Document and Entity Supplemental Information [Abstract] Entities [Table] Entities [Table] Entity Information [Line Items] Entity Information [Line Items] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type 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 Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding 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 Public Float Entity Public Float Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [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] Derivative Instruments and Hedging Activities Disclosure [Abstract] Fair Value of Derivative Instruments Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Offsetting of Natural Gas Derivative Assets and Liabilities 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 Derivative Instruments, Gain (Loss) [Table Text Block] Goodwill and Intangible Assets Disclosure [Text Block] Goodwill and Intangible Assets Disclosure [Text Block] Derivative Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Regulatory Assets and Liabilities, Other Disclosures [Abstract] Regulatory Matters Public Utilities Disclosure [Text Block] Earnings Per Share [Abstract] Earnings Per Share Earnings Per Share [Text Block] 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 2014To2015 [Member] 2014To2015 [Member] Represents the range between the year 2014 to 2015. 2015To2016 [Member] 2015To2016 [Member] 2015To2016 [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Gains (Losses) in Revenue [Member] Sales [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract Type [Domain] Derivative Contract [Domain] 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. Treasury Lock [Member] Treasury Lock [Member] Electric Transmission and 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. Natural Gas Distribution [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Weather Hedge, Bilateral Cap Amount Weather Hedge, Bilateral Cap Amount Represents amount of bilateral cap related to weather hedges. Weather Hedges Term Weather Hedges Term Period of time used as the basis for weather hedges entered into by the company. Derivative, Gain (Loss) on Derivative, Net Derivative, Gain (Loss) on Derivative, Net Aggregate Notional Amount Derivative, Notional Amount Income Tax Disclosure [Abstract] Effective Income Tax Rate Reconciliation, Percent Effective Income Tax Rate Reconciliation, Percent Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Derivative, by Nature [Axis] Derivative, by Nature [Axis] Derivative, Name [Domain] Derivative, Name [Domain] Swap [Member] Swap [Member] Forward Contracts [Member] Forward Contracts [Member] Position [Axis] Position [Axis] Position [Domain] Position [Domain] Long [Member] Long [Member] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Not Designated as Hedging Instrument [Member] Not Designated as Hedging Instrument [Member] Natural gas derivatives [Member] Energy Related Derivative [Member] Indexed debt securities derivative IDS Derivative [Member] Derivative instrument related to indexed debt securities Derivatives, Fair Value, by Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Current Assets [Member] Current Assets [Member] Line item in the statement of financial position in which the fair value amounts of the derivative instruments are included. Other 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 Liabilities [Member] Other Noncurrent Liabilities [Member] Gains (Losses) in Expense: Natural Gas [Member] Cost of Sales [Member] Gains (losses) in Other Income (Expense) [Member] Nonoperating Income (Expense) [Member] Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract] Derivative Asset, Fair Value Derivative Asset, Fair Value, Gross Asset Indexed debt securities derivative Derivative Liability, Fair Value, Gross Liability Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Derivative, Nonmonetary Notional Amount, Volume Derivative, Nonmonetary Notional Amount, Volume Derivative, Fair Value, Net [Abstract] Gross Amounts Recognized Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement Gross Amounts Recognized Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement Gross Amounts Recognized Derivative, Fair Value, Net Gross amounts offset Derivative Asset, Fair Value, Gross Liability and Obligation to Return Cash, Offset Gross amounts offset Derivative Liability, Fair Value, Gross Asset and Right to Reclaim Cash, Offset Gross amounts offset, Net Derivative, Fair Value, Offsets, Net Total of gross amounts offset, net. Derivative Asset Derivative Asset Derivative Liability Derivative Liability Net Amount Presented in the Consolidated Balance Sheets Derivative Assets (Liabilities), at Fair Value, Net Collateral Netting Collateral Netting Amount of collateral netted against derivative contracts. Total fair value of the derivative instruments that contain credit risk contingent features that are in a net liability position Derivative, Net Liability Position, Aggregate Fair Value The aggregate fair value of assets already posted as collateral Collateral Already Posted, Aggregate Fair Value Credit Risk Contingent Features assets Additional Collateral, Aggregate Fair Value Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Continuum Energy Services [Member] Continuum Energy Services [Member] Continuum Energy Services [Member] Redeemable Preferred Stock [Member] Redeemable Preferred Stock [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Business Acquisition, Effective Date of Acquisition Business Acquisition, Effective Date of Acquisition Total Acquisition Cost Payments to Acquire Businesses, Gross Purchase Price Payments To Acquire Businesses, Purchase Price Represents the purchase price of the business acquisition. Purchase Price Adjustment Payments To Acquire Businesses, Purchase Price Adjustment Represents the amount of the purchase price adjustment at the time of acquisition. Working Capital Payments To Acquire Businesses, Adjustment For Working Capital Represents the amount of working capital included in the total consideration at the time of acquisition. Dividends Payable, Date Declared Dividends Payable, Date Declared Preferred Stock, Dividends Per Share, Declared Preferred Stock, Dividends Per Share, Declared Common Stock, Dividends, Per Share, Declared Common Stock, Dividends, Per Share, Declared Dividends Payable, Date to be Paid, Day, Month and Year Dividends Payable, Date to be Paid Dividends Payable, Date of Record, Day, Month and Year Dividends Payable, Date of Record Proceeds from Equity Method Investment, Dividends or Distributions Proceeds from Equity Method Investment, Dividends or Distributions Subsequent Events [Text Block] Subsequent Events [Text Block] Investments, Debt and Equity Securities [Abstract] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] TW Common Member TW Common Member Common stock of Time Warner. TWC Common Member TWC Common Member Common stock of Time Warner Cable. Time Common [Member] Time Common [Member] Time Common [Member] 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. Investment Owned, Balance, Shares Investment Owned, Balance, Shares Debt Instrument, Face Amount Debt Instrument, Face Amount Long-term Debt, Gross 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. Debt Instrument Contingent Principal Amount Outstanding Debt Instrument Contingent Principal Amount Outstanding Amount of outstanding contingent principal under the zero premium exchangeable subordinated notes contract contingent principal clause. Debt Disclosure [Abstract] Short-term Borrowings and Long-term Debt [Text Block] Debt Disclosure [Text Block] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Restricted Stock [Member] Restricted Stock [Member] Net income Net Income (Loss) Attributable to Parent Basic weighted average shares outstanding Weighted Average Number of Shares Outstanding, Basic Plus: Incremental shares from assumed conversions: Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Restricted stock Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Diluted weighted average shares Weighted Average Number of Shares Outstanding, Diluted Basic earnings per share Earnings Per Share, Basic [Abstract] Net income Earnings Per Share, Basic Diluted earnings per share Earnings Per Share, Diluted [Abstract] Net income Earnings Per Share, Diluted Fair Value Disclosures [Abstract] Fair value, assets measured on a recurring basis Fair Value, Assets Measured on Recurring Basis [Table Text Block] Assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Estimated fair value of financial instruments, debt instruments Fair Value, by Balance Sheet Grouping [Table Text Block] Class of Stock Disclosures [Abstract] Capital Stock Stockholders' Equity Note Disclosure [Text Block] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] 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] Depreciation and amortization Depreciation, Depletion and Amortization Amortization of deferred financing costs Amortization of Financing Costs Deferred income taxes Deferred Income Tax Expense (Benefit) Unrealized loss (gain) on marketable securities Marketable Securities, Unrealized Gain (Loss), Excluding Other than Temporary Impairments 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 Equity in (earnings) losses of unconsolidated affiliate, net of distributions Income (Loss) from Equity Method Investments, Net of Dividends or Distributions Pension contributions Pension Contributions Changes in other assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable and unbilled revenues, net Increase (Decrease) in Accounts and Other Receivables 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 Net Cash Provided by (Used in) Operating Activities, Continuing Operations Cash Flows from Investing Activities: Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Capital expenditures Payments to Acquire Productive Assets Decrease in notes receivable – unconsolidated affiliate Repayment of Notes Receivable from Related Parties Investment in preferred units – unconsolidated affiliate Payments to Acquire Investments Distributions from unconsolidated affiliate in excess of cumulative earnings Proceeds from Equity Method Investment, Dividends or Distributions, Return of Capital Decrease (increase) in restricted cash of Bond Companies Increase (Decrease) in Restricted Cash Other, net Payments for (Proceeds from) Other Investing Activities Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Cash Flows from Financing Activities: Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Decrease in short-term borrowings, net Proceeds from (Repayments of) Short-term Debt Payments of commercial paper, net Proceeds from (Repayments of) Commercial Paper Payments of long-term debt Repayments of Long-term Debt Debt issuance costs Payments of Debt Issuance Costs Payment of common stock dividends Payments of Ordinary Dividends, Common Stock Other, net Proceeds from (Payments for) Other Financing Activities Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net Decrease in Cash and Cash Equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and Cash Equivalents at Beginning of Period Cash and Cash Equivalents at End of Period Supplemental Disclosure of Cash Flow Information: Supplemental Cash Flow Information [Abstract] Cash Payments: Cash Payments [Abstract] Interest, net of capitalized interest Interest Paid, Net Income tax refunds, net Income Taxes Paid, Net Non-cash transactions: Noncash Investing and Financing Items [Abstract] Accounts payable related to capital expenditures Capital Expenditures Incurred but Not yet Paid New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Unamortized Debt Issuance Expense Unamortized Debt Issuance Expense Fair Value, Assets Measured on Recurring Basis [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] 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] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Estimate of Fair Value Measurement [Member] Estimate of Fair Value Measurement [Member] Reported Value Measurement [Member] Reported Value Measurement [Member] IDS Derivative [Member] Options Held [Member] Options Held [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Fair Value, Assets Measured on Recurring Basis, Disclosure Items [Axis] Fair Value, Hierarchy [Axis] Fair Value, Assets Measured on Recurring Basis, Disclosure Items [Domain] Fair Value Hierarchy [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] Fair Value, Assets Measured on Recurring Basis, Financial Statement Captions [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] 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. Fair Value Assumptions, Expected Volatility Rate Fair Value Assumptions, Expected Volatility Rate Fair Value, Assets, Level 1 to Level 2 Transfers, Amount Fair Value, Assets, Level 1 to Level 2 Transfers, Amount Fair Value, Assets, Level 2 to Level 1 Transfers, Amount Fair Value, Assets, Level 2 to Level 1 Transfers, Amount Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount Fair Value, Liabilities, Level 2 to Level 1 Transfers, Amount Assets Assets, Fair Value Disclosure [Abstract] 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) Natural gas derivatives, netting adjustment Natural gas derivatives, netting adjustment Derivative Asset, Fair Value, Gross Liability Total assets Assets, Fair Value Disclosure, Recurring Liabilities Liabilities, Fair Value Disclosure [Abstract] Derivative Liability, Fair Value Natural gas derivatives, netting adjustment Natural gas derivatives, netting adjustment Derivative Liability, Fair Value, Gross Asset Derivative Liabilities Total liabilities Liabilities, Fair Value Disclosure, Recurring Cash collateral posted with counterparties Cash collateral posted with counterparties The amount of cash that is posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features. Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [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 Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers out of Level 3 Ending balance (1) The amount of total gains for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held at the reporting date Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Estimated Fair Value of Financial Instruments Additional Fair Value Elements [Abstract] Notes receivable – unconsolidated affiliate Notes Receivable, Fair Value Disclosure Long-term debt Long-term Debt, Fair Value Debt Security [Axis] Debt Security [Axis] Major Types of Debt Securities [Domain] Major Types of Debt Securities [Domain] Indexed Debt Securities [Text Block] Indexed Debt Securities [Text Block] This item represents the entire disclosure related to Indexed Debt Securities (ZENS) and Time Warner Securities. Statement of Comprehensive Income [Abstract] Other Comprehensive Income, Pension and Other Postretirement Benefit Plans, Tax Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax, Portion Attributable to Parent Scenario [Axis] Amount of allowed equity return on the true-up balance that has not been recognized Unrecognized Equity Return Represents the balance of the allowed return on equity that has been deferred and recorded on the balance sheet 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 Net income Other comprehensive income: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Adjustment related to pension and other postretirement plans (net of tax of $1 and $2) Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax, Portion Attributable to Parent Total Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Organization, Consolidation and Presentation of Financial Statements [Abstract] Background and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Compensation and Retirement Disclosure [Abstract] Schedule of Defined Benefit Plans Disclosures [Table Text Block] Schedule of Defined Benefit Plans Disclosures [Table Text Block] Equity Method Investments [Table Text Block] Equity Method Investments [Table Text Block] Description of New Accounting Pronouncements Not yet Adopted [Text Block] Description of New Accounting Pronouncements Not yet Adopted [Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Goodwill [Table Text Block] Schedule of Goodwill [Table Text Block] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plans Disclosures, Defined Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans [Domain] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Pension Plans, Defined Benefit [Member] Pension Plan [Member] Other Postretirement Benefit Plans, Defined Benefit [Member] Other Postretirement Benefit Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Expected return on plan assets Defined Benefit Plan, Expected Return on Plan Assets Amortization of prior service cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Amortization of net loss Defined Benefit Plan, Amortization of Gains (Losses) Settlement cost (2) Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements Net periodic cost Defined Benefit Plan, Net Periodic Benefit Cost Total contributions to the plans during the period Defined Benefit Plan, Contributions by Employer Total contributions expected in 2016 Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year Defined Benefit Plan, Change in Accumulated Comprehensive Loss [Roll Forward] Defined Benefit Plan, Change in Accumulated Comprehensive Loss [Roll Forward] Defined Benefit Plan, Change in Accumulated Comprehensive Loss [Roll Forward] Beginning Balance Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax Amounts reclassified from accumulated other comprehensive loss: Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Actuarial losses (1) Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax Total reclassifications from accumulated other comprehensive loss Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, before Tax Tax expense Net current period other comprehensive income Ending Balance Income Statement [Abstract] Revenues Revenues Expenses: Costs and Expenses [Abstract] Natural gas Cost of Natural Gas Purchases Operation and maintenance Utilities Operating Expense, Maintenance, Operations, and Other Costs and Expenses Taxes other than income taxes Taxes, Miscellaneous 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 f or 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 affiliate, 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, Extraordinary Items, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net Income Basic Earnings Per Share Diluted Earnings Per Share Dividends Declared Per Share Weighted Average Shares Outstanding, Basic Weighted Average Shares Outstanding, Diluted Income Taxes Income Tax Disclosure [Text Block] Equity Method Investment, Summarized Financial Information, Gross Profit (Loss) [Abstract] Equity Method Investment, Summarized Financial Information, Gross Profit (Loss) [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 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 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 Basis Difference Accretion Gain Basis Difference Accretion Gain CenterPoint Energy’s equity in earnings, net Income Loss From Equity Method Investments, Net Of Basis Difference This represents the total income (loss) from equity method investments for the period, net of basis difference. Equity Method Investment, Summarized Financial Information, Assets [Abstract] Equity Method Investment, Summarized Financial Information, Assets [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. 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’ capital 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 Fair Value Disclosures [Text Block] Fair Value Disclosures [Text Block] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Regulatory Asset [Axis] Regulatory Asset [Axis] Regulatory Asset [Domain] Regulatory Asset [Domain] Pension and Other Postretirement Plans Costs [Member] Pension and Other Postretirement Plans Costs [Member] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Intersegment Eliminations [Member] Intersegment Eliminations [Member] Operating Segments [Member] Operating Segments [Member] Segment Reporting Information, by Segment [Axis] Reporting Segment [Domain] Energy Services [Member] Midstream Investments [Member] Midstream Investments [Member] Midstream Investments [Member] Other Operations [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 Energy Future Holdings Corp. [Member] Affiliates of Energy Future Holdings Corp. [Member] Affiliates of Energy Future Holdings Corp. [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Operating Income Assets Assets Regulatory Assets Regulatory Assets Environmental Remediation Site [Axis] Environmental Remediation Site [Axis] Environmental Remediation Site [Domain] Environmental Remediation Site [Domain] Minnesota Service Territory [Member] Minnesota Service Territory [Member] Represents the areas in Minnesota serviced by CERC Litigation Case [Axis] Litigation Case [Axis] Litigation Case [Domain] Litigation Case [Domain] Gas Market Manipulation Cases [Member] Gas Market Manipulation Cases [Member] Represents lawsuits filed against numerous gas market participants in a number of federal and western state courts in connections with the operation of the natural gas markets in 2000-2002. Category of Item Purchased [Axis] Category of Item Purchased [Axis] Long-term Purchase Commitment, Category of Item Purchased [Domain] Long-term Purchase Commitment, Category of Item Purchased [Domain] Natural Gas Supply Commitments [Member] Natural Gas Supply Commitments [Member] Represents natural gas contracts having various quantity requirements and durations classified as "normal purchases contracts" and natural gas transportation contracts. These contracts do not meet the definition of a derivative. Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] GenOn Demand Charges Transportation Contracts [Member] GenOn Demand Charges Transportation Contracts [Member] Represents guarantees for demand charges under certain gas transportation agreements CenterPoint Midstream Guarantees [Member] CenterPoint Midstream Guarantees [Member] Represents guarantees with respect to the performance of certain obligations under long-term gas gathering and treating agreements. Enable Guaranteed Senior Notes [Member] Enable Guaranteed Senior Notes [Member] Represents a guarantee of collection of Enable's senior notes due 2019 and 2024 Natural Gas Supply Commitments Purchase Obligation, Fiscal Year Maturity [Abstract] 2016 Purchase Obligation, Future Minimum Payments, Remainder of Fiscal Year 2017 Purchase Obligation, Due in Second Year 2018 Purchase Obligation, Due in Third Year 2019 Purchase Obligation, Due in Fourth Year 2020 Purchase Obligation, Due in Fifth Year After 2020 Purchase Obligation, Due after Fifth Year Legal Matters Loss Contingency, Information about Litigation Matters [Abstract] Loss Contingency, Pending Claims, Number Loss Contingency, Pending Claims, Number Environmental Matters Environmental Remediation Obligations [Abstract] Liability recorded for remediation of Minnesota sites Accrual for Environmental Loss Contingencies Minimum estimated remediation costs for the Minnesota sites Site Contingency Loss Exposure Estimate of the reasonably possible loss exposure at an individual site. Site Contingency, Years to Resolve Contingency Site Contingency, Years to Resolve Contingency This represents the estimated years necessary to resolve the contingency. Guarantees Guarantees [Abstract] Approximate amount of undiscounted maximum obligation under guarantee Guarantor Obligations, Maximum Exposure, Undiscounted Reportable Business Segments Segment Reporting Disclosure [Text Block] Schedule of Short-term Debt [Table] Schedule of Short-term Debt [Table] Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Product Financing Arrangement [Member] Product Financing Arrangement [Member] Short-term Debt [Line Items] Short-term Debt [Line Items] Total short term borrowings Short-term Debt Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] 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 [Member] Commercial Paper [Member] CenterPoint Houston [Member] CenterPoint Houston [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. Parent Company [Member] Parent Company [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 [Line Items] Debt Instrument [Line Items] Credit Facilities [Abstract] Line of Credit Facility [Abstract] Total credit facility amount Line of Credit Facility, Maximum Borrowing Capacity Debt Instrument, Term Debt Instrument, Term Long-term Line of Credit Long-term Line of Credit Debt, Weighted Average Interest Rate Debt, Weighted Average Interest Rate Basis Spread on LIBOR Debt Instrument, Basis Spread on Variable Rate Percentage on limitation of debt to total capitalization under covenant 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 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) Employee Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Equity Method Investments and Joint Ventures Disclosure [Text Block] Equity Method Investments and Joint Ventures Disclosure [Text Block] Capital stock shares authorized (in shares) Capital Stock Shares Authorized The maximum number of capital shares permitted to be issued by an entity's charter and bylaws. Common stock shares authorized (in shares) Common Stock, Shares Authorized Common stock shares par value (in dollars per share) Common Stock, Par or Stated Value Per Share Cumulative preferred stock shares authorized (in shares) Preferred Stock, Shares Authorized Cumulative preferred stock par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Total common stock issued (in shares) Common Stock, Shares, Issued Treasury stock (in shares) Treasury Stock, Shares Schedule of Line of Credit Facilities [Table Text Block] Schedule of Line of Credit Facilities [Table Text Block] Current Assets: Assets, Current [Abstract] Cash and cash equivalents ($205 and $264 related to VIEs, respectively) Investment in marketable securities Marketable Securities, Current Accounts receivable ($63 and $64 related to VIEs, respectively), less bad debt reserve of $25 and $20, respectively Accrued unbilled revenues Unbilled Receivables, Current Natural gas 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 expenses and other current assets ($39 and $35 related to VIEs, respectively) Total current assets Assets, Current Property, Plant and Equipment: Property, Plant and Equipment [Abstract] Property, plant and equipment Property, Plant and Equipment, Gross Less: accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, plant and equipment, net Property, Plant and Equipment, Net Other Assets: AssetsNoncurrentOtherThanPropertyPlantAndEquipment [Abstract] AssetsNoncurrentOtherThanPropertyPlantAndEquipment [Abstract] Goodwill Regulatory assets ($2,279 and $2,373 related to VIEs, respectively) Notes receivable – unconsolidated affiliate Notes Receivable, Related Parties, Noncurrent Non-trading derivative assets Derivative Asset, Noncurrent Preferred units – unconsolidated affiliate 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 Current Liabilities: Liabilities, Current [Abstract] Short-term borrowings 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 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 Taxes accrued Taxes Payable, Current Interest accrued Interest Payable, 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 Pension and Other Postretirement Defined Benefit Plans, Liabilities, 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 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 Other Long-term Debt, Noncurrent Total long-term debt Long-term Debt, Excluding Current Maturities Commitments and Contingencies (Note 13) Commitments and Contingencies Shareholders’ Equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Common stock (430,614,900 shares and 430,262,703 shares outstanding, respectively) Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Accumulated deficit Retained Earnings (Accumulated Deficit) Accumulated other comprehensive 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