Public Utilities, General Disclosures [Abstract] Electric Rate & Regulatory Matters Public Utilities, General Disclosures - Electric [Text Block] Public Utilities, General Disclosures - Electric [Text Block] Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Utility Group [Member] Utility Group [Member] Nonutility Group [Member] Nonutility Group [Member] Nonutility Group Subsegments [Axis] Subsegments [Axis] Subsegments [Domain] Subsegments [Domain] Infrastructure Services [Member] Infastructure Services [Member] Change in Accounting Estimate by Type [Axis] Change in Accounting Estimate by Type [Axis] Change in Accounting Estimate, Type [Domain] Change in Accounting Estimate, Type [Domain] Change in Accounting Method Accounted for as Change in Estimate [Member] Change in Accounting Method Accounted for as Change in Estimate [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Number of operational groups Number Of Operating Groups Number Of Operating Groups Number of operating segments Number of Operating Segments Portion of Indiana that is provided natural gas distribution and transportation services by the Gas Utility Services segment (in hundredths) Portion Of Indiana That Is Provided Natural Gas Distribution And Transportation Services By Gas Utility Services Segment The percentage of Indiana that is provided natural gas distribution and transportation services by the Gas Utility Services segment. Number of customers (greater than) Number of Customers Number of Customers Fees incurred for pipeline construction and repair services Related Party Transaction, Expenses from Transactions with Related Party Depreciation Depreciation Environmental Matters Disclosure [Abstract] Site Contingency [Table] Site Contingency [Table] Jointly Owned Utility Plant [Axis] Jointly Owned Utility Plant [Axis] Jointly Owned Utility Plant [Domain] Jointly Owned Utility Plant [Domain] OVEC [Member] Jointly Owned Electricity Generation Plant [Member] Unit Name [Axis] Unit Name [Axis] Unit Name Unit Name [Domain] Unit Name [Domain] [Domain] for Unit Name [Axis] Warrick Unit 4 [Member] Warrick Unit 4 [Member] Warrick Unit 4 [Member] Culley Unit 3 [Member] Culley Unit 3 [Member] Culley Unit 3 [Member] AB Brown Unit 1, AB Brown Unit 2 & Culley Unit 2 [Member] AB Brown Unit 1, AB Brown Unit 2 & Culley Unit 2 [Member] AB Brown Unit 1, AB Brown Unit 2 & Culley Unit 2 [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Environmental Remediation Site [Axis] Environmental Remediation Site [Axis] Environmental Remediation by Entity [Domain] Environmental Remediation Site [Domain] Indiana Gas [Member] Indiana Gas [Member] Refers to an entity under the control of the same parent as another entity (that is, a sister company). SIGECO [Member] SIGECO [Member] Refers to an entity under the control of the same parent as another entity (that is, a sister company). Site Contingency [Line Items] Site Contingency [Line Items] Number of public stakeholder meetings to gather input and feedback Number Of Stakeholder Meetings Number Of Stakeholder Meetings Coal-fired generation Public Utilities, Electric Power, Coal-Fired Generation Public Utilities, Electric Power, Coal-Fired Generation Natural gas peaking units Public Utilities, Electric Power, Natural Gas Peaking Units Public Utilities, Electric Power, Natural Gas Peaking Units Landfill-gas-to-electricity facility Public Utilities, Electric Power, Landfill-Gas-To-Electricity Facility Public Utilities, Electric Power, Landfill-Gas-To-Electricity Facility Wind power Public Utilities, Electric Power, Wind Power Generation Public Utilities, Electric Power, Wind Power Generation Number of purchase agreements Public Utilities, Number of Purchase Agreements Public Utilities, Number of Purchase Agreements Period of plan Public Utilities, Period of Plan Public Utilities, Period of Plan Additional solar capacity Public Utilities, Electric Power, Additional Solar Capacity Expected From Twenty Year Plan Public Utilities, Electric Power, Additional Solar Capacity Expected From Twenty Year Plan Current electric capacity under joint operations Public Utilities, Electric Power, Unit Capacity Public Utilities, Electric Power, Unit Capacity Additional capacity from new plant Public Utilities, Electric Power, Additional Capacity Expected From New Plant Public Utilities, Electric Power, Additional Capacity Expected From New Plant Coal Ash Waste Disposal, Ash Ponds and Water [Abstract] Coal Ash Waste Disposal, Ash Ponds and Water [Abstract] Estimated capital expenditures to comply with Ash Pond and Coal Ash disposal regulations Ash Pond and Coal Ash Disposal Exit Costs, Anticipated Cost Total anticipated costs associated with remediation, site restoration, postclosure, monitoring commitments, or other exit costs that may occur on the sale, disposal, or abandonment of a particular property. Ash Pond and Coal Ash Disposal Exit Costs Revised Anticipated Cost Ash Pond and Coal Ash Disposal Exit Costs Revised Anticipated Cost Revised anticipated costs associated with remediation, site restoration, postclosure, monitoring commitments, or other exit costs that may occur on the sale, disposal, or abandonment of a particular property. Asset retirement obligation (ARO) Asset Retirement Obligation Estimated spend for ash pond dam reinforcement and other operational changes Estimated spend for ash pond dam reinforcement and other operational changes Estimated spend for ash pond dam reinforcement and other operational changes Notification period of issuance of the renewal of its intent to retire a unit Notification Period Of Issuance Of Renewal To Retire Unit Notification Period Of Issuance Of Renewal To Retire Unit Estimated capital expenditures to comply with Clean Water Act Estimated capital expenditures to comply with Clean Water Act Estimated capital expenditures related to Clean Water Act granted that new infrastructure is required. Air Quality [Abstract] Air Quality [Abstract] -- None. No documentation exists for this element. -- Percentage of coal fired generating fleet currently being scrubbed for SO2 (in hundredths) Percentage Of Coal Fired Generating Fleet Scrubbed For So2 Percent of coal fired generating fleet currently being scrubbed for SO2. Percentage of coal fired generating fleet currently controlled for NOx (in hundredths) Percentage Of Coal Fired Generating Fleet Controlled For N Ox Percent of coal fired generating fleet currently controlled for Nox. Climate Changes [Abstract] Climate Changes [Abstract] Vectren's share of Indiana's CO2 emissions in 2013 (less than) (as a percent) Vectren's share of Indiana's total CO2 emissions in 2013 (as a percent) Vectren's share of Indiana's total CO2 emissions in 2013 (as a percent) Percent reduction of Vectren's CO2 emissions since 2005 Percent reduction of Vectren's CO2 emissions since 2005 Percent reduction of Vectren's CO2 emissions since 2005 Long term contract for purchase of electric power generated by wind energy (in megawatts) Long Term Contract For Purchase Electric Power Generated From Wind Energy Long Term Contract For Purchase Electric Power Generated From Wind Energy Percentage of total electricity obtained by the supplier to meet the energy needs of its retail customers provided by clean energy sources (in hundredths) Percentage Of Total Electricity Obtained By Supplier To Meet Energy Needs Of Its Retail Customers Provided By Clean Energy Sources In Hundredths Percentage of total electricity obtained by the supplier to meet the energy needs of its retail customers provided by clean energy sources (in hundredths). Vectren's emission rate (as measured in lbs CO2/MWh) prior to installation of new technology Vectren's emission rate (as measured in lbs CO2/MWh) prior to installation of new technology Vectren's emission rate (as measured in lbs CO2/MWh) prior to installation of new technology Vectren's emission rate (as measured in lbs CO2/MWh) after installation of new technology Vectren's emission rate (as measured in lbs CO2/MWh) after installation of new technology Vectren's emission rate (as measured in lbs CO2/MWh) after installation of new technology Percentage reduction of lbs CO2/MWh since 2005 Percentage reduction of lbs CO2/MWh since 2005 Percentage reduction of lbs CO2/MWh since 2005 Manufactured Gas Plants Environmental Remediation Obligations [Abstract] Number of sites identified with potential remedial responsibility for entity (in number of sites) Environmental Remediation Number Of Sites With Potential Remedial Responsibility Number of sites identified where the entity may potentially have some remedial responsibility Cumulative costs recorded Environmental Remediation Expense Insurance coverage, amount received Insurance Recoveries Total estimated insurance recoveries Total Estimated Insurance Recoveries Total amount expected to be recovered under the terms of the insurance contracts. Accrued costs included in Other Liabilities Accrual for Environmental Loss Contingencies Statement of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Net Income (Loss) Attributable to Parent Adjustments to reconcile net income to cash from operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation & amortization Depreciation, Depletion and Amortization Deferred income taxes & investment tax credits Deferred Income Taxes and Tax Credits Provision for uncollectible accounts Provision for Doubtful Accounts Expense portion of pension & postretirement benefit cost Pension and Other Postretirement Benefit Expense Other non-cash items - net Other Noncash Income (Expense) Changes in working capital accounts: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable & accrued unbilled revenues Increase (Decrease) in Receivables Inventories Increase (Decrease) in Inventories Recoverable/refundable fuel & natural gas costs Increase (Decrease) in Recoverable Refundable Gas Costs Prepayments & other current assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable, including to affiliated companies Increase (Decrease) in Accounts Payable Accrued liabilities Increase (Decrease) in Accrued Liabilities Employer contributions to pension & postretirement plans Pension and Other Postretirement Benefit Contributions Changes in noncurrent assets Increase (Decrease) in Other Operating Assets Changes in noncurrent liabilities Increase (Decrease) in Other Operating Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities CASH FLOWS FROM FINANCING ACTIVITIES Net Cash Provided by (Used in) Financing Activities [Abstract] Proceeds from dividend reinvestment plan & other common stock issuances Proceeds from Issuance of Shares under Incentive and Share-based Compensation Plans, Including Stock Options Requirements for: Requirements For Financing Activities [Abstract] Dividends on common stock Payments of Ordinary Dividends, Common Stock Retirement of long-term debt Repayments of Long-term Debt Net change in short-term borrowings Proceeds from (Repayments of) Short-term Debt Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities CASH FLOWS FROM INVESTING ACTIVITIES Net Cash Provided by (Used in) Investing Activities [Abstract] Proceeds from sale of assets and other collections Payments for (Proceeds from) Other Investing Activities Requirements for: Requirements For Investing Activities [Abstract] Capital expenditures, excluding AFUDC equity Payments to Acquire Property, Plant, and Equipment Changes in restricted cash Increase (Decrease) in Restricted Cash Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Net change in cash & cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash & cash equivalents at beginning of period Cash and Cash Equivalents, at Carrying Value Cash & cash equivalents at end of period Pension and Other Postretirement Benefit Expense [Abstract] Retirement Plans & Other Postretirement Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Current Assets Assets, Current [Abstract] Cash & cash equivalents Accounts receivable - less reserves of $6.6 & $6.0, respectively Accounts Receivable, Net, Current Accrued unbilled revenues Accrued unbilled revenues Unbilled amounts due for services rendered or products shipped. Also includes cost of uncompleted contracts in excess of related billings, or unbilled accounts receivable, which is expected to be collected withon one year (or one operating cycle, if longer) from the date of the balance sheet. Inventories Inventory, Net Recoverable fuel & natural gas costs Deferred Fuel Cost Prepayments & other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current Utility Plant Property, Plant and Equipment [Abstract] Original cost Public Utilities, Property, Plant and Equipment, Other Property, Plant and Equipment Less: accumulated depreciation & amortization Public Utilities, Property, Plant and Equipment, Accumulated Depreciation Net utility plant Public Utilities, Property, Plant and Equipment, Net Investments in unconsolidated affiliates Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Other utility & corporate investments Other Investments Other nonutility investments Other nonutility investments Other long-term nonutility investments not classified elsewhere in the taxonomy. Nonutility plant - net Property, Plant and Equipment, Net Goodwill Goodwill Regulatory assets Regulatory Assets, Noncurrent Other assets Other Assets, Noncurrent TOTAL ASSETS Assets LIABILITIES & SHAREHOLDERS' EQUITY Liabilities and Equity [Abstract] Current Liabilities Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued liabilities Accrued Liabilities, Current Short-term borrowings Short-term Debt Current maturities of long-term debt Long-term Debt, Current Maturities Total current liabilities Liabilities, Current Long-term Debt - Net of Current Maturities Long-term Debt, Excluding Current Maturities Deferred Credits & Other Liabilities Liabilities, Noncurrent [Abstract] Deferred income taxes Deferred Income Tax Liabilities, Net Regulatory liabilities Regulatory Liability, Noncurrent Deferred credits & other liabilities Deferred Credits and Other Liabilities Total deferred credits & other liabilities Liabilities, Noncurrent Commitments & Contingencies (Notes 7-11) Commitments and Contingencies Common Shareholders' Equity Stockholders' Equity Attributable to Parent [Abstract] Common stock (no par value) – issued & outstanding 83.0 & 82.9, respectively Common Stock, Value, Issued Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Total common shareholders' equity Stockholders' Equity Attributable to Parent TOTAL LIABILITIES & SHAREHOLDERS' EQUITY Liabilities and Equity Environmental & Sustainability Matters Environmental Loss Contingency Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments & Contingencies Commitments and Contingencies Disclosure [Text Block] Gas Rate & Regulatory Matters Public Utilities General Disclosures - Gas [Text Block] Public Utilities General Disclosures - Gas [Text Block] Equity Method Investments and Joint Ventures [Abstract] Summarized Financial Information of Equity Investment Summarized Financial Information of Equity Investment [Table Text Block] Tabular disclosure of financial information of ProLiance Holdings, LLC. Income Statement [Abstract] OPERATING REVENUES Revenue, Net [Abstract] Gas utility Regulated Operating Revenue, Gas Electric utility Electric Domestic Regulated Revenue Nonutility Other Revenue, Net Total operating revenues Revenue, Net OPERATING EXPENSES Operating Expenses [Abstract] Cost of gas sold Cost of Natural Gas Purchases Cost of fuel & purchased power Cost of Domestic Regulated Electric Cost of nonutility revenues Other Cost of Operating Revenue Other operating Other Cost and Expense, Operating Depreciation & amortization Taxes other than income taxes Taxes other than income taxes All taxes not related to income of the entity. Total operating expenses Operating Expenses OPERATING INCOME Operating Income (Loss) OTHER INCOME Nonoperating Income (Expense) [Abstract] Equity in (losses) of unconsolidated affiliates Income (Loss) from Equity Method Investments Other income – net Other Nonoperating Income (Expense) Total other income Nonoperating Income (Expense) INTEREST EXPENSE Interest Expense INCOME BEFORE INCOME TAXES Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest INCOME TAXES Income Tax Expense (Benefit) NET INCOME AND COMPREHENSIVE INCOME WEIGHTED AVERAGE AND DILUTED COMMON SHARES OUTSTANDING (in shares) Weighted Average Number of Shares Outstanding, Basic DILUTED COMMON SHARES OUTSTANDING (in shares) Weighted Average Number of Shares Outstanding, Diluted BASIC AND DILUTED EARNINGS PER SHARE OF COMMON STOCK (in dollars per share) Earnings Per Share, Basic and Diluted DIVIDENDS DECLARED PER SHARE OF COMMON STOCK (in dollars per share) Common Stock, Dividends, Per Share, Declared Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments [Member] Operating Segments [Member] Eliminations [Member] Intersegment Eliminations [Member] Corporate & Other Group [Member] Corporate, Non-Segment [Member] Eliminations [Member] Consolidation, Eliminations [Member] Gas Utility Services [Member] Electric Utility Services [Member] Other Operations [Member] Parent [Member] Energy Services [Member] Other Businesses [Member] Revenues Public Utilities General Disclosures [Table] Public Utilities General Disclosures [Table] Geographical [Axis] Geographical [Axis] Geographical [Domain] Geographical [Domain] INDIANA [Member] INDIANA OHIO [Member] OHIO Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Domain] Public Utilities, Regulatory Proceeding [Domain] Indiana Recovery and Deferral Mechanisms [Member] Indiana Recovery and Deferral Mechanisms [Member] Indiana Recovery and Deferral Mechanisms [Member] Senate Bill 251 and 560 [Member] Senate Bill 251 and 560 [Member] Senate Bill 251 and 560 [Member] Ohio Recovery and Deferral Mechanisms [Member] Ohio Recovery and Deferral Mechanisms [Member] Ohio Recovery and Deferral Mechanisms [Member] Ohio House Bill 95 [Member] Ohio House Bill95 [Member] Information on the Ohio House Bill 95. Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Public Utilities, General Disclosures [Line Items] Public Utilities, General Disclosures [Line Items] Allowable capital expenditures under Vectren programs Allowable capital expenditures under Vectren programs Annual Capital Expenditures under the Vectren bare steel and cast iron main replacement program allowed to receive preferred accounting treatment (deferred depreciation and continuation of AFUDC after the in-service date). Limitations of deferrals of debt-related post in service carrying costs Limitations of deferrals of debt-related post in service carrying costs Limitations of deferrals of debt-related post in service carrying costs Length of project plan required for recovery under new legislation Length of project plan required for recovery under new legislation Length of project plan required for recovery under new legislation Amount of project investment approved Expected Seven Year Period Modernization Investment Expected Seven Year Period Modernization Investment Amount of project investment not approved for recovery Expected Seven Year Period Modernization Investment, Not Approved For Recovery Expected Seven Year Period Modernization Investment, Not Approved For Recovery Capital expenditure increase Capital Expenditure Increases Amount of capital expenditure increases included in update to seven-year plan. Project spend life to date Project spend life to date Project spend life to date Capital expenditures under plan Total Capital Expenditures Under Seven Year Plan Total Capital Expenditures Under Seven Year Plan Additional capital investment Additional Capital Investment Under Plan Additional Capital Investment Under Plan Payments for capital improvements Payments for Capital Improvements Bill impact per customer per month Impact on Customer Bill Per Month The limit on the deferrals, represented as a bill impact per customer per month, allowed under VEDO's Capital Expenditure Program filed under Ohio House Bill 95. Document and Entity Information [Abstract] Entity Registrant Name Entity Central Index Key Current Fiscal Year End Date Entity Filer Category Document Type Document Period End Date Document Fiscal Year Focus Document Fiscal Period Focus Amendment Flag Entity Common Stock, Shares Outstanding Excise and Utility Receipts Taxes [Abstract] Excise & Utility Receipts Taxes Excise and Utility Receipts Taxes [Text Block] Description containing information regarding excise and utility receipts taxes as a single block of text. Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investment, Equity Method Investee, Name [Axis] Investment, Name [Axis] Equity Method Investee, Name [Domain] Investment, Name [Domain] Proliance Holdings LLC [Member] Proliance Holdings Llc [Member] Information related to the legal entity ProLianceHoldings, LLC. LA Storage [Member] LA Storage [Member] LA Storage [Member] Corporate Joint Venture [Member] Corporate Joint Venture [Member] Affiliated Entity [Member] Affiliated Entity [Member] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Ownership share (as a percent) Equity Method Investment, Ownership Percentage Voting rights (as a percent) Equity Method Investment, Voting and Governance Rights Equity method investment, voting and governance rights Summarized balance sheet information [Abstract] Equity Method Investment, Summarized Financial Information [Abstract] Cash Equity method investment, Summarized Financial Information, Cash The amount of cash reported by an equity method investment of the entity. Investment in LA Storage Equity Method investment, Summarized Financial Information, Storage Assets The amount of the storage assets reported by an equity method investment of the entity. Other midstream asset investment Equity Method investment, Summarized Financial Information, Other Asset Investment The amount of other asset investments reported by an equity method investment of the entity. Total investment in ProLiance Equity method investment, gross investment in equity method investee Equity method investment, gross investment in equity method investee Ownership interest (as a percent) Combined Joint Venture Ownership Percentage Equity method investment, combined joint venture ownership percentage Investment in joint venture Equity Method Investments Earnings Per Share [Abstract] Basic and Dilutive EPS Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Reserves Allowance for Doubtful Accounts Receivable, Current Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Fair Value Disclosures [Abstract] Carrying value of notes receivable Notes Receivable, Fair Value Disclosure Organization, Consolidation and Presentation of Financial Statements [Abstract] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Natural Gas Customers [Member] Natural Gas Customers [Member] Natural Gas Customers [Member] Electric Customers [Member] Electric Customers [Member] Electric Customers [Member] VEDO [Member] Vectren Energy Delivery of Ohio [Member] Vectren Energy Delivery of Ohio [Member] Public utilities subsidiaries owned by wholly owned subsidiary Number Of Public Utility Subsidiaries Owned By Wholly Owned Subsidiary Of Company Pertains to the number of public utility subsidiaries owned by wholly owned subsidiary, Vectren Utility Holdings, Inc. Approximate number of customers Approximate Number Of Customers Pertains to the approximate number customers serviced by the Company. Number of primary business areas Number Of Primary Business Areas Number Of Primary Business Areas Fair Value By Balance Sheet Grouping Fair Value, by Balance Sheet Grouping [Table Text Block] Net Periodic Benefit Costs Schedule of Defined Benefit Plans Disclosures [Table Text Block] Excise and utility receipts taxes billed to customers Excise Taxes Collected Basis of Presentation [Abstract] Basis of Presentation Basis of Presentation and Significant Accounting Policies [Text Block] Supplemental Cash Flow Information [Abstract] Accruals related to utility and nonutility plant purchases Capital Expenditures Incurred but Not yet Paid Supplemental Cash Flow Information Cash Flow, Supplemental Disclosures [Text Block] Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] Energy Systems Group [Member] Energy Systems Group [Member] Energy Systems Group [Member] Guarantor Obligations by Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Performance Guarantee [Member] Performance Guarantee [Member] Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] Corporate Guarantees [Abstract] Guarantees [Abstract] Performance Guarantees and Product Warranties [Abstract] Performance Guarantees Product Warranties [Abstract] Number of surety bonds open to support future performance Number Of Surety Bond Obligations Outstanding For Wholly Owned Subsidiary Represents the absolute number of surety bonds the wholly owned subsidiary has outstanding in its role as general contractor Face amount of surety bonds outstanding Performance Guarantee Obligations Outstanding Face Amount Face amount of individual surety bonds the wholly owned subsidiary has outstanding. Work yet to be completed on surety bond projects (as a percent) Percentage Of Work Yet to be Completed On Projects With Open Surety Bonds Percentage of work yet to be completed on projects with open surety bonds Period for release of significant portion of surety bonds Guarantor Obligation Term Guarantor Obligation Term Warranty liability recognized Standard and Extended Product Warranty Accrual Maximum exposure by parent company on guarantees Guarantor Obligations, Maximum Exposure, Undiscounted Letters of credit outstanding Letters of Credit Outstanding, Amount Firm purchase commitment term one Purchase Commitment Contract Term One Purchase Commitment Contract Term One Firm purchase commitment term two Purchase Commitment Contract Term Two Purchase Commitment Contract Term Two Earnings Per Share Earnings Per Share [Text Block] Accounting Changes and Error Corrections [Abstract] New Accounting Pronouncements and Changes in Accounting Principles [Abstract] New Accounting Pronouncements and Changes in Accounting Principles [Abstract] Impact of Recently Issued Accounting Principles New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Numerator: Numerator [Abstract] Reported net income (Numerator for Basic and Diluted EPS) Denominator: Denominator [Abstract] Weighted average common shares outstanding (Denominator for Basic EPS) (in shares) Conversion of share based compensation arrangements (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Adjusted weighted-average shares outstanding and assumed conversions outstanding (Denominator for Diluted EPS) (in shares) Basic and Diluted EPS (in dollars per share) Electric Modernization Program - SB 560 [Member] Electric Modernization Program - SB 560 [Member] Electric Modernization Program - SB 560 [Member] Renewable Generation - SB 29 [Member] Renewable Generation - SB 29 [Member] Renewable Generation Project - SB 29 [Member] Electric Demand Side Management Program [Member] Electric Demand Side Management Filing [Member] Electric Demand Side Management Filing [Member] Number of solar projects filed for authority to recover costs Number Of Solar Projects With Authority To Recover Costs Number Of Solar Projects With Authority To Recover Costs Additional solar generation resulting from project Public Utilities, Electric Power, Additional Solar Generation Resulting From Project Public Utilities, Electric Power, Additional Solar Generation Resulting From Project Additional battery storage resources resulting from project Public Utilities, Electric Power, Additional Battery Storage Resources Resulting From Project Public Utilities, Electric Power, Additional Battery Storage Resources Resulting From Project Estimated cost of project Estimated Capital Expenditures Under Project Plan Estimated Capital Expenditures Under Project Plan Amount of capital investments to date in equipment for mercury control Amount of capital investments to date in equipment for mercury control Amount of capital investments to date in equipment for coal fired generation units to control mercury emissions in air and water. Amount of capital investments to date in equipment to control sulfur trioxide emissions Amount of capital investments to date in equipment to control sulfur trioxide emissions Amount of capital investments to date in equipment to control sulfur trioxide emissions. Estimated cost of equipment to comply with MATS Estimated cost of equipment to comply with MATS Estimated cost of equipment to comply with MATS Estimated cost of equipment required by the NOV Estimated cost of equipment required by the NOV Estimated cost of equipment required by the NOV Vectren South Electric Demand Side Management Program Filing [Abstract] Vectren South Electric Demand Side Management Program Filing [Abstract] Vectren South Electric Demand Side Management Program Filing [Abstract] Initial DSM plan period Number of Years in Initial Demand Side Management Program Number of Years in Initial Demand Side Management Program Electric utility revenue Maximum period for recovery under energy efficiency program Maximum period for recovery under energy efficiency program Maximum period for recovery under energy efficiency program FERC Return On Equity Complaint [Abstract] FERC Return On Equity Complaint [Abstract] FERC Return On Equity Complaint [Abstract] Current return on equity used in MISO transmission owners rates Current return on equity used in MISO transmission owners rates Current return on equity percentage used in MISO transmission owners rates, which includes SIGECO's formula transition rates. Reduced return on equity percentage sought by third party through joint complaint Reduced return on equity percentage sought by third party through joint complaint Reduced return on equity percentage sought by third party under joint complaint filed with the FERC under Section 206 of the Federal Power Act against MISO and various MISO transmission owners, including SIGECO. FERC authorized base ROE percentage for first refund period FERC authorized base ROE percentage for first refund period FERC authorized base ROE percentage FERC authorized base ROE percentage for second refund period FERC authorized base ROE percentage for second refund period FERC authorized base ROE percentage for second refund period FERC authorized incentive ROE percentage for first refund period FERC Authorized Incentive ROE Percentage for First Refund Period FERC Authorized Incentive ROE Percentage for First Refund Period Gross investment in qualifying projects Gross Investment In Qualifying Transmission Projects Gross investment in qualifying electric transmission projects constructed by the Company in its service territory that meet certain MISO criteria. Net plant balance for qualifying projects Net Investment in Qualifying Transmission Projects Net investment in qualifying electric transmission projects constructed by the Company in its service territory that meet certain MISO criteria. Organization and Nature of Operations Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Segment Reporting Segment Reporting Disclosure [Text Block] Number of qualified defined benefit pension plans Number Of Defined Benefit Pension Plans Number Of Defined Benefit Pension Plans Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Pension Benefits [Member] Pension Plan [Member] Other Benefits [Member] Other Postretirement Benefit Plan [Member] Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [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 actuarial loss Defined Benefit Plan, Amortization of Gains (Losses) Net periodic cost (benefit) Defined Benefit Plan, Net Periodic Benefit Cost Expected contribution to defined benefit plans for current year by employer Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year Fair Value, by Balance Sheet Grouping [Table] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Amount [Member] Reported Value Measurement [Member] Estimated Fair Value [Member] Estimate of Fair Value Measurement [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Long-term debt Long-term Debt, Fair Value Short-term borrowings Short-term Debt, Fair Value Cash & cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Restricted cash Restricted Cash and Cash Equivalents, Current Investment in ProLiance Holdings, LLC Equity Method Investments and Joint Ventures Disclosure [Text Block] Fair Value Measurements Fair Value Disclosures [Text Block] Schedule of Segment Reporting Schedule of Segment Reporting Information, by Segment [Table Text Block]