Fair Value Disclosures [Abstract] Fair Value Disclosures [Text Block] Fair Value Disclosures [Text Block] Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Bonds General Mortgage Due 2044 [Member] Bonds General Mortgage Due 2044 [Member] Bonds General Mortgage Due 2044 [Member] 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] Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] March 2014 [Member] March 2014 [Member] March 2014 [Member] June 2014 [Member] June 2014 [Member] June 2014 [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Bonds Pollution Control Due2017 [Member] Bonds Pollution Control Due2017 [Member] A debt security issued by a state, certain agencies or authorities, a local government, or development corporation to finance the construction of air- or water-pollution control facilities or sewage or solid waste disposal facilities pursuant to federal law. Bonds Pollution Control Due2027 [Member] Bonds Pollution Control Due2027 [Member] A debt security issued by a state, certain agencies or authorities, a local government, or development corporation to finance the construction of air- or water-pollution control facilities or sewage or solid waste disposal facilities pursuant to federal law. Bank loans due 2016 [Member] Line of Credit [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Midstream Partnership [Member] Midstream Partnership [Member] Midstream Partnership [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. 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. 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. Debt Instrument [Line Items] Debt Instrument [Line Items] Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Maturity Date Debt Instrument, Maturity Date Extinguishment Of Debt Purchase Price Percentage Of Principal Extinguishment Of Debt Purchase Price Percentage Of Principal Repurchase price of debt obligations expressed as a percentage of principal amount Extinguishment of Debt, Amount Extinguishment of Debt, Amount Total short term borrowings Short-term Debt Debt Instrument, Face Amount Debt Instrument, Face Amount Long-term Debt [Abstract] Long-term Debt, by Current and Noncurrent [Abstract] Total credit facility amount Line of Credit Facility, Maximum Borrowing Capacity Loans Outstanding Line of Credit Facility, Amount Outstanding Letters of Credit outstanding Letters of Credit Outstanding, Amount Commercial Paper Outstanding Long-term Commercial Paper Revolving credit facility borrowing rate Line of Credit Facility, Interest Rate Description 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. 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) Commitments and Contingencies Disclosure [Abstract] Recorded Unconditional Purchase Obligation [Table] Recorded Unconditional Purchase Obligation [Table] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Schedule of Capital Expansion Projects, by Project [Axis] Schedule of Capital Expansion Projects, by Project [Axis] A table of capital expansion projects by project. Capital Expansion Project [Domain] Capital Expansion Project [Domain] The capital expansion projects by name. Recorded Unconditional Purchase Obligation [Line Items] Recorded Unconditional Purchase Obligation [Line Items] Recorded Unconditional Purchase Obligation Recorded Unconditional Purchase Obligation, Fiscal Year Maturity Schedule [Abstract] Remainder of 2014 Recorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year 2015 Recorded Unconditional Purchase Obligation Due in Next Twelve Months 2016 Recorded Unconditional Purchase Obligation Due in Second Year 2017 Recorded Unconditional Purchase Obligation Due in Third Year 2018 Recorded Unconditional Purchase Obligation Due in Fourth Year After 2018 Recorded Unconditional Purchase Obligation Due after Fourth Year Recorded Unconditional Purchase Obligation Due after Fourth Year Loss Contingency Pending Gas Market Manipulation Lawsuits Number Loss Contingency Pending Gas Market Manipulation Lawsuits Number The total number of pending lawsuits related to gas market manipulation. Legal Environmental And Other Regulatory Matters LegalEnvironmentalAndOtherRegulatoryMattersLegalMattersGasMarketManipulationCasesAbstract Number of remaining sites in the Minnesota service territory (in number of sites) Site Contingency Remaining Minnesota Sites Number of other sites in the company's Minnesota service territory. Number of the remaining sites in the Minnesota service territory where the company believes it has no liability (in number of sites) Site Contingency Sites Without Liability Number of sites in Minnesota where the company believes it has no liability. Number of sites where remediation is complete, other than ongoing operations (in number of sites) Site Contingency Completed Remediation Number of manufactured gas plant sites where remediation is complete, other than ongoing operations. Amount accrued for remediation of Minnesota sites (in number of sites) Accrual for Environmental Loss Contingencies Maximum estimated remediation costs for the Minnesota sites Site Contingency Loss Exposure Estimate of the reasonably possible loss exposure at an individual site. Years of remediation for the Minnesota sites (in years) Site Contingency, Estimated Time Frame to Resolve Contingency Annual amount included in rates to fund normal on-going remediation costs Environmental Costs Recognized, Recovery Credited to Expense Amount collected from insurance companies to be used for future environmental remediation Recorded Third-Party Environmental Recoveries, Amount Approximate amount of undiscounted maximum obligation under guarantee Guarantor Obligations, Maximum Exposure, Undiscounted Guarantee Obligations Maximum Amount Upon Completion Of Gathering Systems Guarantee Obligations Maximum Amount Upon Completion Of Gathering Systems Maximum amount of guarantees reduce to plus any additional amounts related to expansion of services upon completion of gathering systems. Compensation and Retirement Disclosure [Abstract] Schedule of Defined Benefit Plans Disclosures [Table Text Block] Schedule of Defined Benefit Plans Disclosures [Table Text Block] Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table Text Block] Statement of Comprehensive Income [Abstract] Statement [Table] Scenario [Axis] Statement [Line Items] Net income (loss) Net Income (Loss) Attributable to Parent 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 $2, $1, $3 and $3) Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Total Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Regulatory Assets and Liabilities, Other Disclosures [Abstract] Amount of allowed equity return on the true-up balance that has not been recognized Unrecognized Amount Of Allowed Equity Return Amount of allowed equity return on the true-up balance that has not been recognized as it will be recognized as it is recovered in rates. 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 Earnings Per Share [Abstract] Earnings Per Share Earnings Per Share [Text Block] 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] Energy Services [Member] Corporate and Other [Member] Goodwill [Line Items] Goodwill [Line Items] Goodwill Goodwill Equity Method Investments and Joint Ventures [Abstract] Equity Method Investments and Joint Ventures Disclosure [Text Block] Equity Method Investments and Joint Ventures Disclosure [Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Short-term Borrowings and Long-term Debt [Text Block] Debt Disclosure [Text Block] Subsequent Events [Abstract] Subsequent Events [Text Block] Subsequent Events [Text Block] Statement of Financial Position [Abstract] Statement [Line Items] Current Assets: Assets, Current [Abstract] Cash and cash equivalents ($188 and $207 related to VIEs, respectively) Cash and Cash Equivalents, at Carrying Value Investment in marketable securities Marketable Securities, Current Accounts receivable ($94 and $60 related to VIEs, respectively), less bad debt reserve of $26 and $28, respectively Accounts Receivable, Net, Current 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 Prepaid expenses and other current assets ($51 and $41 related to VIEs, respectively) Prepaid Expense and Other Assets, Current 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: Assets, Noncurrent [Abstract] Goodwill Regulatory assets ($2,971 and $3,179 related to VIEs, respectively) Regulatory Assets, Noncurrent Notes receivable - affiliated companies Due from Affiliate, Noncurrent Non-trading derivative assets Derivative Asset, Noncurrent Investment in unconsolidated affiliates Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Other Other Assets, Noncurrent Total other assets Assets, Noncurrent Total Assets Assets Current Liabilities: Liabilities, Current [Abstract] Short-term borrowings Current portion of VIE transition and system restoration 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 Accumulated deferred income taxes, net Deferred Tax Liabilities, Net, Current Other Other Liabilities, Current Total current liabilities Liabilities, Current Other Liabilities: Liabilities, Noncurrent [Abstract] Accumulated 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, Noncurrent Long-term Debt: Long-term Debt, Excluding Current Maturities [Abstract] VIE transition and system restoration bonds Transition And System Restoration Bonds Long Term Debt Non Current Other Other Long-term Debt, Noncurrent Total long-term debt Long-term Debt, Excluding Current Maturities Commitments and Contingencies (Note 12) Commitments and Contingencies Shareholders’ Equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Common stock (429,795,830 shares and 428,798,446 shares outstanding, respectively) Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital Retained earnings 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 Schedule of Line of Credit Facilities [Table Text Block] Schedule of Line of Credit Facilities [Table Text Block] Class of Stock Disclosures [Abstract] Capital Stock Stockholders' Equity Note Disclosure [Text Block] Regulatory Matters Public Utilities Disclosure [Text Block] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Segment Reporting Information, by Segment [Axis] Reporting Segment [Domain] 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] Energy Services [Member] Interstate Pipelines [Member] Interstate Pipelines [Member] Segment information for the Interstate Pipelines segment which includes the interstate natural gas pipeline operations. Field Services [Member] Field Services [Member] Segment information for the Field Services business segment which includes the natural gas gathering, treating and processing operations. Midstream Investments [Member] Midstream Investments [Member] Midstream Investments [Member] Other Operations [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] Consolidation, Eliminations [Member] Consolidation, Eliminations [Member] CERC Remaining Interest in SESH [Member] CERC Remaining Interest in SESH [Member] CERC Remaining Interest in SESH [Member] SESH [Member] SESH [Member] SESH [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] Equity Method Investment, Additional Contribution of Ownership Percentage Equity Method Investment, Additional Contribution of Ownership Percentage Equity Method Investment, Additional Contribution of Ownership Percentage Revenues Revenues Operating Income (Loss) Operating Income (Loss) Assets Equity in earnings of unconsolidated affiliates, net Income (Loss) from Equity Method Investments Segment Reporting Pension Plan Assets Segment Reporting Pension Plan Assets This represents the assets recognized in the Other Operations segment that are associated with the defined benefit plans. Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Income Tax Disclosure [Abstract] Effective Income Tax Rate Reconciliation, Percent Effective Income Tax Rate Reconciliation, Percent Deferred Tax Liabilities, Goodwill and Intangible Assets Deferred Tax Liabilities, Goodwill and Intangible Assets Deferred income taxes Deferred Income Tax Expense (Benefit) 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, Defined Benefit [Member] Other Postretirement Benefit Plans, Defined Benefit [Member] Other Postretirement Benefit Plan, Defined Benefit [Member] Other Pension Plans, Postretirement or Supplemental Plans, Defined Benefit [Member] Other Pension Plan, Postretirement or Supplemental Plans, Defined Benefit [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 (credit) Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Amortization of net loss Defined Benefit Plan, Amortization of Gains (Losses) Amortization of transition obligation Defined Benefit Plan, Amortization of Transition Obligations (Assets) 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 2014 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 Amounts reclassified from accumulated other comprehensive loss: Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract] Prior service cost (1) Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost, Recognized in Net Periodic Benefit Cost, before tax Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Prior Service Cost, Recognized in Net Periodic Benefit Cost, before tax Actuarial losses (1) Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Actuarial gains, Recognized in Net Periodic Benefit Cost, before tax Other Comprehensive Income (Loss), Reclassification, Pension and Other Postretirement Benefit Plans, Net Actuarial gains, Recognized in Net Periodic Benefit Cost, before tax Total reclassifications from accumulated other comprehensive loss OtherComprehensiveIncomeLossReclassificationOfDefinedBenefitPlansNetGainLossRecognizedInNetPeriodicCostBeforeTax Before tax amount of the income statement impact of the reclassification adjustment recognized as a component of net periodic benefit cost Tax expense Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax, Portion Attributable to Parent Net current period other comprehensive income Ending Balance Income Statement [Abstract] Expenses: Operating Expenses [Abstract] Natural gas Cost of Natural Gas Purchases Operation and maintenance Operation and maintenance The amount of operating expense for the period for recurring costs associated with normal operations including general and administrative expenses, and routine plant mainentnance and repairs. Depreciation and amortization Depreciation, Depletion and Amortization Taxes other than income taxes Taxes, Miscellaneous Total Operating Expenses Operating Income Other Income (Expense): Nonoperating Income (Expense) [Abstract] Gain on marketable securities Marketable Securities, Gain (Loss) Loss on indexed debt securities Gain (loss) on Indexed Debt Securities Gain (loss) on Indexed Debt Securities. Interest and other finance charges Interest and Debt Expense Interest on transition and system restoration bonds Interest on Transition and System Restoration Bonds Interest on Transition and System Restoration Bonds. 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 (Loss) Basic Earnings (Loss) Per Share Earnings Per Share, Basic Diluted Earnings (Loss) Per Share Earnings Per Share, Diluted Dividends Declared Per Share Common Stock, Dividends, Per Share, Declared Weighted Average Shares Outstanding, Basic Weighted Average Number of Shares Outstanding, Basic Weighted Average Shares Outstanding, Diluted Weighted Average Number of Shares Outstanding, Diluted Derivative Instruments and Hedging Activities Disclosure [Abstract] Fair Value of Derivative Instruments Table Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Income Statement Impact of Derivative Activity Table Derivative Instruments, Gain (Loss) [Table Text Block] Fair Value, Assets Measured on Recurring Basis [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] 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] Reported Value Measurement [Member] Reported Value Measurement [Member] Estimate of Fair Value Measurement [Member] Estimate of Fair Value Measurement [Member] Derivative, by Nature [Axis] Derivative, by Nature [Axis] Derivative, Name [Domain] Derivative, Name [Domain] Forward Contracts [Member] Forward Contracts [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] Netting Adjustments [Member] Netting [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] Illiquid forward price per mmbtu Underlying, Derivative Energy Measure Option volatilities Option volatilities Option volatilities Assets Assets [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 Investments, Fair Value Disclosure Natural gas derivatives Derivative Asset, Fair Value, Gross Asset Natural gas derivatives, netting adjustment Derivative Asset, Fair Value, Gross Liability Natural gas derivatives, assets Derivative Asset Total assets Assets, Fair Value Disclosure, Recurring Liabilities Liabilities [Abstract] Natural gas derivatives Derivative Liability, Fair Value, Gross Liability Natural gas derivatives, netting adjustment Derivative Liability, Fair Value, Gross Asset Natural gas derivatives, liabilities Derivative Liability 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. Derivative Instruments, Assets, Physical Forwards Purchased Derivative Instruments, Assets, Physical Forwards Purchased Derivative Instruments, Assets, Physical Forwards Purchased Notes Receivable, Fair Value Disclosure Notes Receivable, Fair Value Disclosure Long-term Debt Long-term Debt, Fair Value Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Beginning balance Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Net Asset Liability Value This element represents the net asset/liability measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances. Total gains Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Total settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, (Sales), Issuances, (Settlements) Transfers into Level 3 Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Inputs Reconciliation, Transfers, Net 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 Amount Of Total Gains Losses For Period Included In Earnings This item represents the amount of the total change in unrealized (holding) gains or losses for the period which are included in the statement of income (or changes in net assets) in assets still held at reporting period. Such unrealized (holding) gains or losses relate to those assets still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3). Statement [Table] Variable Interest Entity, Primary Beneficiary [Member] Variable Interest Entity, Primary Beneficiary [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Total common stock outstanding (in shares) Common Stock, Shares, Outstanding Cash and cash equivalents Bad Debt Reserve Allowance for Doubtful Accounts Receivable, Current Accounts receivable, net Prepaid expenses and other current assets Regulatory assets 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 Equity Method Investments [Table Text Block] Equity Method Investments [Table Text Block] Other Comprehensive Income, Pension and Other Postretirement Benefit Plans, Tax Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax Organization, Consolidation and Presentation of Financial Statements [Abstract] Background and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Statement of Cash Flows [Abstract] Cash Flows from Operating Activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income 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 Financing Costs Unrealized gain on marketable securities Marketable Securities, Unrealized Gain (Loss) Unrealized loss on indexed debt securities Indexed Debt Securities, Unrealized Gain (Loss) Indexed Debt Securities, Unrealized Gain (Loss) Write-down of natural gas inventory Inventory Write-down Equity in earnings of unconsolidated affiliates, 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 Commodity Contract 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 Increase (Decrease) in Other Operating Assets and Liabilities, Net 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 [Abstract] Capital expenditures Payments to Acquire Productive Assets Decrease (increase) in restricted cash of transition and system restoration bond companies Increase (Decrease) in Restricted Cash Payments to Acquire Interest in Subsidiaries and Affiliates Payments to Acquire Interest in Subsidiaries and Affiliates Cash contribution to Enable Cash Contributed Cash Contributed Proceeds from sale of marketable securities Proceeds from Sale and Maturity of Marketable Securities 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 [Abstract] Decrease in short-term borrowings, net Proceeds from (Repayments of) Short-term Debt Payment of commercial paper, net Proceeds from (Repayments of) Commercial Paper Proceeds from long-term debt Proceeds from Issuance of Long-term Debt Payments of long-term debt Repayments of Long-term Debt Cash paid for debt retirement Payments of Debt Extinguishment Costs Debt issuance costs Payments of Debt Issuance Costs Redemption of indexed debt securities Redemption of Indexed Debt Securities Redemption of Indexed Debt Securities 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 taxes, net Income Taxes Paid, Net Non-cash transactions: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Accounts payable related to capital expenditures Capital Expenditures Incurred but Not yet Paid Derivative Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Description of New Accounting Pronouncements Not yet Adopted [Text Block] Description of New Accounting Pronouncements Not yet Adopted [Text Block] Reportable Business Segments Segment Reporting Disclosure [Text Block] 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] Subsequent Event [Table] Subsequent Event [Table] Equity Method Investee, Name [Axis] Investment, Name [Axis] Equity Method Investee, Name [Domain] Investment, Name [Domain] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Dividends [Axis] Dividends [Axis] Dividends [Domain] Dividends [Domain] Dividend Declared [Member] Dividend Declared [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Dividends Payable, Date Declared Dividends Payable, Date Declared Dividends Payable, Amount Per Share Dividends Payable, Amount Per Share 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 Common Stock [Member] Common Stock [Member] Subordinated Units [Member] Subordinated Units [Member] Subordinated Units [Member] Equity Contribution Period [Axis] Equity Contribution Period [Axis] Equity Contribution Period [Axis] Equity Contribution Period [Domain] Equity Contribution Period [Domain] [Domain] for Equity Contribution Period [Axis] May 2014 [Member] May 2014 [Member] May 2014 [Member] OGE [Member] OGE [Member] OGE [Member] ArcLight [Member] ArcLight [Member] ArcLight [Member] Term Loan of Affiliate Indebtedness to CERC 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 (Expense), Net Interest Receivable Interest Receivable Transitional Services Costs to be Reimbursed Transitional Service Costs to be Reimbursed Transitional Service Costs to be Reimbursed Transitional Service cost receivable Transitional Services Receivable Transitional Services Receivable Partners' Capital Account, Public Sale of Units Net of Offering Costs Partners' Capital Account, Units, Sold in Public Offering Sale of Stock, Price Per Share Share Price Proceeds from Issuance Initial Public Offering Proceeds from Issuance Initial Public Offering Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest Incentive Distribution Right Incentive Distribution Right Incentive Distribution Right Equity Method Investment, Ownership Percentage Equity Method Investment, Ownership Percentage equity method investment, Additional Contribution of ownership, value equity method investment, Additional Contribution of ownership, value equity method investment, Additional Contribution of ownership, value Cost of natural gas purchases, affiliates Cost of natural gas purchases, affiliates Cost of natural gas purchased and associated transportation and storage costs during the period from unconsolidated affiliates Due to Affiliate Due to Affiliate, Current Equity Method Investment, Ownership, Shares Equity Method Investment, Ownership, Shares Equity Method Investment, Ownership, Shares 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 Fnancial Information, Operating Income Equity Method Investment, Summarized Fnancial Information, Operating Income Net income attributable to Enable Equity Method Investment, Summarized Financial Information, Net Income (Loss) CenterPoint Energy's approximate interest Gross equity in earnings Gross equity in earnings Basis difference accretion (amortization) Basis Difference Accretion Gain Basis Difference Accretion Gain Basis Difference Amortization Basis Difference Amortization Basis Difference Amortization CenterPoint Energy's equity in earnings, net 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 Enable partners' capital Equity Method Investment Summarized Financial Information, Equity CenterPoint Energy's ownership interest in Enable's partner capital Equity Method Investment, Underlying Equity in Net Assets Total CenterPoint Energy's basis differences equity method investment, basis difference, Total equity method investment, basis difference, Total CenterPoint Energy's investment in Enable Equity Method Investments Underlying Equity in Net Assets, Net of Basis Difference Equity Method Investments Underlying Equity in Net Assets, Net of Basis Difference Proceeds from Equity Method Investment, Dividends or Distributions Proceeds from Equity Method Investment, Dividends or Distributions Income Loss From Equity Method Investments, net of basis difference Income Loss From Equity Method Investments, net of basis difference Income Loss From Equity Method Investments, net of basis difference Income Taxes Income Tax Disclosure [Text Block] Schedule of Goodwill [Table Text Block] Schedule of Goodwill [Table Text Block] Basic weighted average shares outstanding Plus: Incremental shares from assumed conversions: Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract] Stock options Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Restricted stock Incremental Common Shares Attributable to Dilutive Effect of Contingently Issuable Shares Diluted weighted average shares Basic earnings (loss) per share: Earnings Per Share, Basic [Abstract] Net income (loss) Diluted earnings (loss) per share: Earnings Per Share, Diluted [Abstract] Net income (loss) 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 Number Of Vies Consolidated In Financial Statements Number Of Vies Consolidated In Financial Statements The number of variable interest entities (VIE's) consolidated in the financials. Employee Benefit Plans Pension and Other Postretirement Benefits Disclosure [Text Block] year range [Axis] year range [Axis] year range [Axis] year range [Domain] year range [Domain] [Domain] for year range [Axis] 2012 - 2013 [Member] 2012 - 2013 [Member] 2012 - 2013 [Member] 2013 - 2014 [Member] 2013 - 2014 [Member] 2013 - 2014 [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] Derivative Instrument [Axis] Derivative Contract Type [Domain] Derivative Contract [Domain] Natural gas derivatives [Member] Commodity Contract [Member] Indexed Debt Securities Derivative [Member] Other Contract [Member] 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 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 Liabilities [Member] Income Statement Location [Axis] Income Statement and Other Comprehensive Income Location [Domain] Income Statement Location [Domain] Gains (Losses) in Revenue [Member] Sales [Member] Gains (Losses) in Expense: Natural Gas [Member] Cost of Sales [Member] Gains (losses) in Other Income (Expense) [Member] Other Expense [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Weather Hedge, Amount, maximum Weather Hedge, Amount, maximum Weather Hedge Caps Term of normal weather used as the basis for weather hedges (in years) Weather Hedges Term Period of time used as the basis for weather hedges entered into by the company. Gains (Losses) Recognized Related to Weather Hedges Derivative, Gain (Loss) on Derivative, Net Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract] Derivative Asset, Fair Value Derivative Liability, Fair Value Derivative gross volumes on natural gas contracts (MMcf) Derivative Gross Volumes on Natural Gas Contracts Derivative Gross Volumes on Natural Gas Contracts Net long position (MMcf) Derivative Gross Volume Long Position Net long position volume amount taken by the company in its natural gas derivative contracts. Amount of net long position constituted by basis swaps (MMcf) Derivative Gross Volume Basis Swaps Long Position The amount of net long position constituted by basis swaps. Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Derivative Instruments physical purchase Derivative Instruments Physical Forwards Purchased Derivative Instruments Physical Forwards Purchased Derivative, Fair Value, Net [Abstract] Gross Amounts Recognized Derivative Asset, Fair Value, Amount Offset Against Collateral Gross Amounts Recognized Derivative Liability, Fair Value, Amount Offset Against Collateral Gross Amounts Recognized Derivative, Fair Value, Net Gross Amounts Offset in the Consolidated Balance Sheets Gross Amounts Offset in the Consolidated Balance Sheets Net Amount Presented in the Consolidated Balance Sheets Derivative, Fair Value, Amount Offset Against Collateral, Net Derivative, fair value, offsets, net Derivative, fair value, offsets, net Derivative, fair value, offsets, net 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 Goodwill and Intangible Assets Disclosure [Text Block] Goodwill and Intangible Assets Disclosure [Text Block]