Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Description of Business Nature of Operations [Text Block] Document Fiscal Year Focus Document Fiscal Year Focus Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Increase (Decrease) in Prepaid Expense Increase (Decrease) in Prepaid Expense Measurement Basis [Axis] Measurement Basis [Axis] Other deferred credits Other Liabilities, Noncurrent Segment Reporting [Abstract] Segment Reporting [Abstract] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Common stock Common Stock, Value, Issued Common Stock, Value, Issued Public Utilities, General Disclosures [Line Items] Public Utilities, General Disclosures [Line Items] Schedule of Long-term Debt Instruments Schedule of Long-Term Debt Instruments [Table Text Block] Pension and Postretirement Benefits Retirement Benefits [Text Block] Accrued taxes Taxes Payable, Current Retained Earnings [Member] Retained Earnings [Member] Revolving Credit Facility [Member] Revolving Credit Facility [Member] Money Market Funds [Member] Money Market Funds [Member] Public Utilities, Allowance for Funds Used During Construction, Additions Public Utilities, Allowance for Funds Used During Construction, Additions Expected return on assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets Fair Value Measurement Inputs and Valuation Techniques Fair Value Measurement Inputs and Valuation Techniques [Table Text Block] Common Stock, Shares, Outstanding Common Stock, Shares, Outstanding Entity Current Reporting Status Entity Current Reporting Status Schedule of Effective Income Tax Rate Reconciliation Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Net cash provided by financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Retail Revenue [Member] Retail Revenue [Member] Retail Revenue [Member] Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits Accounts Receivable, Allowance for Credit Loss Accounts Receivable, Allowance for Credit Loss Regulatory liabilities, non-current Regulatory Liability, Noncurrent Unrealized Gain (Loss) on Investments Unrealized Gain (Loss) on Investments Amendment Flag Amendment Flag Current liabilities: Liabilities, Current [Abstract] Consolidated Entities [Axis] Consolidated Entities [Axis] Accounts Receivable, Credit Loss Expense (Reversal) Accounts Receivable, Credit Loss Expense (Reversal) 5.70% Senior Notes due 2033 5.70% Senior Notes due 2033 [Member] 5.70% Senior Notes due 2033 Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Operation and maintenance Utilities Operating Expense, Maintenance and Operations Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Accounts Receivable, Allowance for Credit Loss, Writeoff Accounts Receivable, Allowance for Credit Loss, Writeoff Revenue from Contract with Customer, Excluding Assessed Tax Revenue from Contract with Customer, Excluding Assessed Tax Cash flows from financing activities: Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization Property, Plant, and Equipment, after Accumulated Depreciation, Depletion, and Amortization Interest cost Defined Benefit Plan, Interest Cost Equity ownership interest aggregate cost Equity Ownership Interest - Guaranteed Portion of Long-term Debt Obligation Equity ownership interest guaranteed portion of Long-term Debt Obligation Receivables from Contracts with Customers Receivables from Contracts with Customers [Table Text Block] Receivables from Contracts with Customers Total non-current liabilities Liabilities, Noncurrent Consolidated Entities [Domain] Consolidated Entities [Domain] Payments of Deferred Finance Costs Payments of Deferred Finance Costs Payments of Deferred Finance Costs Schedule of Cash and Cash Equivalents [Table Text Block] Schedule of Cash and Cash Equivalents [Table Text Block] Entity Address, City or Town Entity Address, State or Province Industrial Revenue Industrial Revenue [Member] Industrial Revenue Utility [Member] Utility [Member] Utility [Member] Public Utility, Property, Plant and Equipment [Table] Public Utility, Property, Plant and Equipment [Table] Revenue Type [Axis] Revenue Type [Axis] Information by type of revenue Estimate of Fair Value Measurement [Member] Fair Value [Member] Estimate of Fair Value Measurement [Member] Revenue from Contract with Customer [Text Block] Revenue from Contract with Customer [Text Block] Par value common shares (in USD per share) Common stock, par value (in USD per share) Common Stock, Par or Stated Value Per Share Segment Reporting, Long-Lived Asset, Expenditure for Addition Segment Reporting, Long-Lived Asset, Expenditure for Addition Subsegments [Domain] Subsegments [Domain] Increase (Decrease) in Interest Payable, Net Increase (Decrease) in Interest Payable, Net Intangible Asset, Excluding Goodwill, after Accumulated Amortization Intangible Asset, Excluding Goodwill, after Accumulated Amortization Non-current liabilities: Liabilities, Noncurrent [Abstract] Equity [Table] Equity [Table] Equity Revenue [Abstract] Revenue [Abstract] Revenue [Abstract] RTO Revenue RTO Revenue RTO Revenue Subsegments [Axis] Subsegments [Axis] Payment for (Proceeds from) Other Investing Activity Payment for (Proceeds from) Other Investing Activity Increase (Decrease) in Inventories Increase (Decrease) in Inventories Regulatory Asset, Noncurrent Regulatory Asset, Noncurrent Ohio Holdings Investment Percent Ohio Holdings Investment Percent Ohio Holdings Investment Percent Service area, square miles Service Area Square Miles Service area square miles Number of reportable segments Number of Reportable Segments Common Stock, Value, Issued Common Stock, Value, Issued [Member] Common Stock, Value, Issued Total current liabilities Liabilities, Current Liabilities, Current Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] [Line Items] for Significant Accounting Policies [Table] Subsegments Consolidation Items [Axis] Subsegments Consolidation Items [Axis] Segment Reporting [Table] Segment Reporting [Table] Contractual Obligations, Commercial Commitments And Contingencies [Abstract] Contractual Obligations, Commercial Commitments And Contingencies [Abstract] Contractual Obligations, Commercial Commitments and Contingencies [Abstract] Taxes other than income taxes Taxes, Miscellaneous Equity ownership interest Public utilities equity interest, cost method, percentage The noncontrolling equity interest in an electric generation company, accounted for under the cost method of accounting. Allowance for Funds Used During Construction, Equity Portion Allowance for Funds Used During Construction, Equity Portion Allowance for Funds Used During Construction, Equity Portion Schedule of Related Party Transactions, by Related Party [Table] Related Party Transaction [Table] Other Assets, Current Other Assets, Current Entity Address, City or Town Entity Address, City or Town Operating Income (Loss), Total Operating Income (Loss) Taxes payable Taxes Payable Current Fiscal Year End Date Current Fiscal Year End Date Other Revenues [Member] Other Revenues [Member] Other Revenues [Member] Unbilled Revenue Unbilled Revenue Amounts due from customers based upon an estimate of sales of power to customers since the last customer billing. Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Financial Statement Presentation Basis of Accounting, Policy [Policy Text Block] Allowance For Funds Used During Construction / Capitalized Interest Allowance For Funds Used During Construction / Capitalized Interest [Table Text Block] Allowance For Funds Used During Construction / Capitalized Interest Derivative activity: Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract] Related Party Transaction [Domain] Related Party Transaction [Domain] Commercial Revenue Commercial Revenue [Member] Commercial Revenue Payments of Ordinary Dividends Payments of Ordinary Dividends Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum Upper Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum Upper Range Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum Upper Range Level 2 [Member] Fair Value, Inputs, Level 2 [Member] Entity File Number Entity File Number Service cost Defined Benefit Plan, Service Cost Line of Credit Facility, Maximum Borrowing Capacity Line of Credit Facility, Maximum Borrowing Capacity Other Comprehensive Income (Loss), Net of Tax, Total Other Comprehensive Income (Loss), Net of Tax Other Comprehensive Income (Loss), Net of Tax Long-Term Debt, Current Maturities Long-Term Debt, Current Maturities Allowance for Funds Used During Construction, Capitalized Interest Allowance for Funds Used During Construction, Capitalized Interest Debt Obligation on 4.9% Equity Ownership [Member] Debt Obligation On 49 Equity Ownership [Member] Debt Obligation on 4.9% Equity Ownership in an electric generation company Common stock, shares issued Common Stock, Shares, Issued 5.19% First Mortgage Bonds due 2033 5.19% First Mortgage Bonds due 2033 [Member] 5.19% First Mortgage Bonds due 2033 Schedule of Long-term Debt Instruments [Table] Schedule of Long-Term Debt Instruments [Table] Entity Information [Line Items] Entity Information [Line Items] Long-term Debt, Current and Noncurrent [Abstract] Long-Term Debt, Current and Noncurrent [Abstract] Deferred Finance Costs, Net, Including Acquisition Adjustments Unamortized deferred finance costs Deferred Finance Costs, Net, Including Acquisition Adjustments Deferred Finance Costs, Net, Including Acquisition Adjustments Recently Issued Accounting Standards New Accounting Pronouncements, Policy [Policy Text Block] New Accounting Pronouncements, Policy [Policy Text Block] Accruals for capital expenditures Capital Expenditures Incurred but Not yet Paid Payments for (Proceeds from) Removal Costs Payments for (Proceeds from) Removal Costs Financial Reporting for Reportable Business Segments Segment Reporting [Table Text Block] Equity Components [Axis] Equity Components [Axis] Product and Service [Domain] Product and Service [Domain] Related Party Related Party [Member] Related Party, Type [Axis] Related and Nonrelated Parties [Axis] Contributions in Aid of Construction Contributions in Aid of Construction Increase (Decrease) in Current Regulatory Assets and Liabilities Increase (Decrease) in Current Regulatory Assets and Liabilities The increase (decrease) during the reporting period in the value of assets that are created when regulatory agencies permit public utilities to defer costs (revenues) to the balance sheet. This element is the increase (decrease) of current regulatory assets and liabilities combined Increase (Decrease) in Regulatory Assets and Liabilities Increase (Decrease) in Regulatory Assets and Liabilities Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Other non-606 revenue Other non-606 revenue Other non-606 revenue Repayments of Lines of Credit Repayments of Lines of Credit Entity Interactive Data Current Entity Interactive Data Current Long-term Debt Total long-term debt Long-Term Debt Deferred Tax Liabilities, Net Deferred Income Tax Liabilities, Net Electric Generation Company [Member] Electric Generation Company [Member] The Electric Generation Company DP&L holds a 4.9% interest. Proceeds from Contributions from Parent Proceeds from Contributions from Parent Non-cash financing and investing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Increase (Decrease) in Income Taxes Payable Increase (Decrease) in Income Taxes Payable Entity Small Business Entity Small Business Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive Income (Loss), Net of Tax, Attributable to Parent Document Period End Date Document Period End Date Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity, Increase (Decrease) in Operating Capital [Abstract] Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax Property, Plant, and Equipment [Line Items] Property, Plant, and Equipment [Line Items] Cash Provided by (Used in) Investing Activity, Including Discontinued Operation, Total Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Subsidiaries [Member] Subsidiaries [Member] Effective Income Tax Rate Reconciliation [Table] Effective Income Tax Rate Reconciliation [Table] Excise taxes collected Excise Taxes Collected Stockholders' Equity Note Disclosure Equity [Text Block] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Debt Instrument, Interest Rate, Effective Percentage Debt Instrument, Interest Rate, Effective Percentage Other current liabilities Other Liabilities, Current Other Assets, Noncurrent Other Assets, Noncurrent Document Type Document Type Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Overview and Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Revenue from Contracts with Customers Revenue from Contracts with Customers [Table Text Block] Revenue from Contracts with Customers Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Shell Company Entity Shell Company Consolidation Items [Domain] Consolidation Items [Domain] Cash and Cash Equivalent Cash and Cash Equivalent [Abstract] Accounting for Taxes Collected from Customers and Remitted to Governmental Authorities Regulatory Income Taxes, Policy [Policy Text Block] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Accounts Receivable, Allowance for Credit Loss Accounts Receivable, Allowance for Credit Loss [Table Text Block] Proceeds from Issuance of Long-term Debt Proceeds from Issuance of Long-Term Debt Accrued interest Interest Payable, Current Local Phone Number Local Phone Number Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Consolidation Items [Axis] Consolidation Items [Axis] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Document Fiscal Period Focus Document Fiscal Period Focus Reclassification to earnings, net of income tax Other Comprehensive Income (Loss), Defined Benefit Plan, Transition Asset (Obligation), Reclassification Adjustment from AOCI, after Tax Other Comprehensive Income (Loss), Defined Benefit Plan, Transition Asset (Obligation), Reclassification Adjustment from AOCI, after Tax Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Liabilities Liabilities Liabilities Revenues Revenues Purchased power Utilities Operating Expense, Purchased Power Approximate number of retail customers Number Of Retail Customers This element represents the approximate number of retail customers that electricity is generated and distributed within the company's service territory. 5.70% Tax-exempt First Mortgage Bonds due 2033 5.70% Tax-exempt First Mortgage Bonds due 2033 [Member] 5.70% Tax-exempt First Mortgage Bonds due 2033 LIABILITIES AND SHAREHOLDER'S EQUITY Liabilities and Equity [Abstract] Amortization of Debt Issuance Costs and Discounts Amortization of Debt Issuance Costs and Discounts Fair Value of Assets and Liabilities Measured on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Reclassifications Reclassifications [Text Block] Inventories Inventory, Net Fair Value Fair Value Disclosures [Text Block] Level 3 [Member] Fair Value, Inputs, Level 3 [Member] Taxes Applicable to Subsequent Years Taxes Applicable to Subsequent Years Carrying amount as of the balance sheet date of capitalized property and other taxes which will be charged against earnings within one year or the normal operating cycle, if longer. Long-term Debt, Gross Long-Term Debt, Gross Supplemental Cash Flow Information Supplemental Cash Flow Information [Abstract] Uncommitted Accordion Feature Uncommitted Accordion Feature Uncommitted Accordion Feature Significant Accounting Policies [Table] Significant Accounting Policies [Table] Significant Accounting Policies [Table] Increase (Decrease) in Other Accrued Liabilities Increase (Decrease) in Other Accrued Liabilities Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Asset Types [Domain] Asset Class [Domain] Credit Facility [Domain] Credit Facility [Domain] Cash flows from operating activities: Cash Provided by (Used in) Operating Activity, Including Discontinued Operation [Abstract] Restricted Cash Restricted Cash Shares, Issued Shares, Issued Long-Lived Asset, Class [Axis] Long-Lived Asset, Class [Axis] Segment Reporting, Other Segment Item, Amount Segment Reporting, Other Segment Item, Amount Entity Emerging Growth Company Entity Emerging Growth Company Related Party Transaction [Line Items] Related Party Transaction [Line Items] Pension, retiree and other benefits Liability, Defined Benefit Plan, Noncurrent Disposal Group Name [Domain] Disposal Group Name [Domain] Entity Tax Identification Number Entity Tax Identification Number Proceeds from Lines of Credit Proceeds from Lines of Credit Mutual Fund Mutual Fund [Member] Entities [Table] Entities [Table] Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Continuing Operation Depreciation and amortization Depreciation, Depletion and Amortization, Including Discontinued Operation Depreciation, Depletion and Amortization, Including Discontinued Operation Increase (Decrease) in Accounts Payable Increase (Decrease) in Accounts Payable Contributions by employer Defined Benefit Plan, Plan Assets, Contributions by Employer Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Other Other Receivables Increase (Decrease) in Other Operating Assets and Liabilities, Net Increase (Decrease) in Other Operating Assets and Liabilities, Net Wholesale Revenue [Member] Wholesale Revenue [Member] Wholesale Revenue [Member] Debt Instrument [Axis] Debt Instrument [Axis] Revenue Type [Domain] Revenue Type [Domain] Revenue Type Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Disposal Group Name [Axis] Disposal Group Name [Axis] Subsegments Consolidation Items [Domain] Subsegments Consolidation Items [Domain] Investment, Name [Domain] Investment, Name [Domain] Effective income tax rates Effective Income Tax Rate Reconciliation, Percent Proceeds from Contribution in Aid of Construction, Investing Activity Proceeds from Contribution in Aid of Construction, Investing Activity Revenue Requirement - Three-Year Rate Plan (2029) Revenue Requirement - Three-Year Rate Plan (2029) Revenue Requirement - Three-Year Rate Plan (2029) Contract with Customer, Liability, Current Contract with Customer, Liability, Current Revenue Requirement - Three-Year Rate Plan (2028) Revenue Requirement - Three-Year Rate Plan (2028) Revenue Requirement - Three-Year Rate Plan (2028) Assets, Current, Total Assets, Current Revenue Requirement - Three-Year Rate Plan (2027) Revenue Requirement - Three-Year Rate Plan (2027) Revenue Requirement - Three-Year Rate Plan (2027) Long-term debt Long-Term Debt, Excluding Current Maturities 4.00% Tax-exempt First Mortgage Bonds due 2027 4.00% Tax-exempt First Mortgage Bonds due 2027 [Member] 4.00% Tax-exempt First Mortgage Bonds due 2027 Rate Base - Three-Year Rate Plan (2027) Rate Base - Three-Year Rate Plan (2027) Rate Base - Three-Year Rate Plan (2027) Rate Base - Three-Year Rate Plan (2028) Rate Base - Three-Year Rate Plan (2028) Rate Base - Three-Year Rate Plan (2028) Accounts Receivable, after Allowance for Credit Loss, Current Accounts Receivable, after Allowance for Credit Loss, Current Retained Earnings (Accumulated Deficit) Retained Earnings (Accumulated Deficit) CDPQ Investment percent CDPQ Investment Percent CDPQ Investment Percent Product and Service [Axis] Product and Service [Axis] Interest expense Interest expense Interest and Debt Expense Rate Base - Three-Year Rate Plan (2029) Rate Base - Three-Year Rate Plan (2029) Rate Base - Three-Year Rate Plan (2029) Governmental Revenue Governmental Revenue [Member] Governmental Revenue Pension [Member] Pension Plan [Member] Common Stock [Member] Common Stock [Member] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Pension and postretirement activity: Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax [Abstract] Cover [Abstract] Cover [Abstract] Regulatory [Table] Regulatory [Table] Regulatory Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Business Segments Segment Reporting [Text Block] Long-term Line of Credit Long-Term Line of Credit Public Utilities General Disclosures [Table] Public Utilities General Disclosures [Table] Investments, Fair Value Disclosure Investments, Fair Value Disclosure Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Disaggregation of Revenue [Table Text Block] Disaggregation of Revenue [Table Text Block] Total liabilities and shareholder's equity Liabilities and Equity 4.55% First Mortgage Bond Due 2030 4.55% First Mortgage Bond Due 2030 [Member] 4.55% First Mortgage Bond Due 2030 Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Current portion of long-term debt Debt, Current Nonrelated Party Nonrelated Party [Member] Segments [Axis] Segments [Axis] Disposal Group, Including Discontinued Operations [Line Items] Disposal Group, Including Discontinued Operations [Line Items] Asset Class [Axis] Asset Class [Axis] Net periodic benefit cost Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Related Party, Type [Domain] Related and Nonrelated Parties [Domain] Schedule of Supplemental Financial Information Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Common Stock, Shares Authorized Common Stock, Shares Authorized Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum Unrealized Gain (Loss) on Investments Unrealized Gain (Loss) on Investments [Table Text Block] Other Nonoperating Income (Expense) Other Nonoperating Income (Expense) Debt Instrument, Unamortized Discount (Premium), Net Debt Instrument, Unamortized Discount (Premium), Net Return on Equity - Three-Year Rate Plan Return on Equity - Three-Year Rate Plan Return on Equity - Three-Year Rate Plan Cash Provided by (Used in) Investing Activity, Including Discontinued Operation Cash Provided by (Used in) Investing Activity, Including Discontinued Operation [Abstract] Income Taxes Receivable, Current Income Taxes Receivable, Current Related Party Transaction [Axis] Related Party Transaction [Axis] Common shareholder's equity: Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Segment Reporting [Line Items] Segment Reporting [Line Items] Regulatory Matters [Abstract] Regulatory Matters [Abstract] Regulatory Matters Abstract Document Quarterly Report Document Quarterly Report Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] RTO Capacity Revenue RTO Capacity Revenue RTO Capacity Revenue Long-Lived Asset, Class [Domain] Long-Lived Asset, Class [Domain] Segments [Domain] Segments [Domain] Schedule of Net Periodic Benefit Cost / (Income) Schedule of Net Periodic Benefit Cost / (Income) [Table Text Block] Schedule of Net Periodic Benefit Cost / (Income) [Table Text Block] 3.95% Senior Notes due 2049 [Member] 3.95% Senior Notes due 2049 [Member] 3.95% Senior Notes due 2049 [Member] Regulatory Liability Regulatory Liability Property, Plant, and Equipment [Table] Property, Plant, and Equipment [Table] Long-term Debt Debt Disclosure [Text Block] 5.49% Senior Notes due 2028 5.49% Senior Notes due 2028 [Member] 5.49% Senior Notes due 2028 3.25% First Mortgage Bonds due 2040 [Member] 3.20% First Mortgage Bonds due 2040 [Member] 3.20% First Mortgage Bonds due 2040 Disposal Group Classification [Domain] Disposal Group Classification [Domain] Residential Revenue Residential Revenue [Member] Residential Revenue Equity Component [Domain] Equity Component [Domain] Capital Structure - Long-term Debt - Three-Year Rate Plan (2029) Capital Structure - Long-term Debt - Three-Year Rate Plan (2029) Capital Structure - Long-term Debt - Three-Year Rate Plan (2029) Capital Structure - Long-term Debt - Three-Year Rate Plan (2028) Capital Structure - Long-term Debt - Three-Year Rate Plan (2028) Capital Structure - Long-term Debt - Three-Year Rate Plan (2028) Interest Paid, Excluding Capitalized Interest, Operating Activity Interest Paid, Excluding Capitalized Interest, Operating Activity Payments to Acquire Productive Assets Payments to Acquire Productive Assets Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Capital Structure - Long-term Debt - Three-Year Rate Plan (2027) Capital Structure - Long-term Debt - Three-Year Rate Plan (2027) Capital Structure - Long-term Debt - Three-Year Rate Plan (2027) RSC Rider RSC Rider RSC Rider Costs and Expenses Costs and Expenses Inventory, Policy Inventory, Policy [Policy Text Block] Credit Facility [Axis] Credit Facility [Axis] Debt instrument interest percentage Debt Instrument, Interest Rate, Stated Percentage Total Assets Assets, Fair Value Disclosure Schedule of Regulatory Assets and Liabilities [Text Block] Schedule of Regulatory Assets and Liabilities [Text Block] Equity, Attributable to Parent, Total Equity, Attributable to Parent Debt obligation Long-Term Debt and Lease Obligation Nonoperating Income (Expense), Total Nonoperating Income (Expense) Discontinued Operations and Disposal Groups [Abstract] Discontinued Operations and Disposal Groups [Abstract] Income Taxes Income Tax Disclosure [Text Block] Accounts payable Accounts Payable, Current Debt [Member] Debt [Member] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] U.S. Government note maturing in February 2061 - 4.20% [Member] Four Point Two Zero Percentage Of U S Government Note Maturing In February Two Thousand Sixty One [Member] Four Point Two Zero Percentage Of U S Government Note Maturing In February Two Thousand Sixty One [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Accounting Policies [Abstract] Accounting Policies [Abstract] Other Additional Capital [Member] Other Additional Capital [Member] Retirement Benefits, Description [Abstract] Retirement Benefits, Description [Abstract] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Additional Paid-in Capital Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Accounts Receivable, Allowance for Credit Loss, Current Accounts Receivable, Allowance for Credit Loss, Current Repayments of Short-Term Debt Repayments of Short-Term Debt Deferred Income Tax Expense (Benefit) Deferred Income Tax Expense (Benefit) Cost of Long-term Debt - Three-Year Rate Plan (2027) Cost of Long-term Debt - Three-Year Rate Plan (2027) Cost of Long-term Debt - Three-Year Rate Plan (2027) Regulatory Asset, Current Regulatory Asset, Current Cost of Long-term Debt - Three-Year Rate Plan (2028) Cost of Long-term Debt - Three-Year Rate Plan (2028) Cost of Long-term Debt - Three-Year Rate Plan (2028) Cost of Long-term Debt - Three-Year Rate Plan (2029) Cost of Long-term Debt - Three-Year Rate Plan (2029) Cost of Long-term Debt - Three-Year Rate Plan (2029) Cash and Cash Equivalent Cash and Cash Equivalent Cash and Cash Equivalent Contractual Obligations, Commercial Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Number of Operating Segments Number of Operating Segments Depreciation and amortization Depreciation, Depletion and Amortization Entity Central Index Key Entity Central Index Key Property, Plant, and Equipment, Accumulated Depreciation, Depletion, and Amortization Property, Plant, and Equipment, Accumulated Depreciation, Depletion, and Amortization Other paid-in capital Additional Paid in Capital, Common Stock Equity [Abstract] Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Cash Provided by (Used in) Operating Activity, Including Discontinued Operation Capital Structure - Equity - Three-Year Rate Plan (2027) Capital Structure - Equity - Three-Year Rate Plan (2027) Capital Structure - Equity - Three-Year Rate Plan (2027) Capital Structure - Equity - Three-Year Rate Plan (2028) Capital Structure - Equity - Three-Year Rate Plan (2028) Capital Structure - Equity - Three-Year Rate Plan (2028) Capital Structure - Equity - Three-Year Rate Plan (2029) Capital Structure - Equity - Three-Year Rate Plan (2029) Capital Structure - Equity - Three-Year Rate Plan (2029) Stockholders' Equity, Other Stockholders' Equity, Other Stockholders' Equity, Other Income Statement [Abstract] Income Statement [Abstract] Document Transition Report Document Transition Report Entity Address, Address Line One Entity Address, Address Line One Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Investment, Name [Axis] Investment, Name [Axis] Income Tax Expense (Benefit) Income Tax Expense (Benefit) Income Tax Expense (Benefit) Estimated annual effective income tax rate Estimated Annual Effective Income Tax Rate, Continuing Operations A ratio calculated by dividing the estimated amount of annual income tax expense attributable to continuing operations by GAAP-basis estimated annual pretax income from continuing operations. Customer receivables Customer receivables Amounts due from customers for billed utility services. Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation 5.49% Tax-exempt First Mortgage Bonds due 2028 5.49% First Mortgage Bonds due 2028 [Member] 5.49% First Mortgage Bonds due 2028 City Area Code City Area Code Actuarial loss / (gain) Defined Benefit Plan, Amortization of Gain (Loss) Net Income (Loss) Attributable to Parent, Total Net Income (Loss) Attributable to Parent AOCI Attributable to Parent [Member] AOCI Attributable to Parent [Member] Statement [Table] Statement [Table] Debt Debt Instrument, Fair Value Disclosure Payments of Dividends Payments of Dividends Payments of Dividends Increase (Decrease) in Taxes Applicable to Subsequent Years Increase (Decrease) in Taxes Applicable to Subsequent Years The net change during the reporting period in the aggregate value of capitalized property and other taxes, associated with underlying transactions that are classified as operating activities. Regulatory liabilities, current Regulatory Liability, Current Schedule of Accumulated Other Comprehensive Income (Loss) Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Public Utility, Property, Plant and Equipment [Line Items] Public Utility, Property, Plant and Equipment [Line Items] 4.25% Tax-exempt First Mortgage Bonds due 2027 4.25% Tax-exempt First Mortgage Bonds due 2027 [Member] 4.25% Tax-exempt First Mortgage Bonds due 2027 Assets, Noncurrent, Total Assets, Noncurrent Statement [Line Items] Statement [Line Items] Increase (Decrease) in Receivables Increase (Decrease) in Receivables Total assets Assets Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plan [Table] Effective Income Tax Rate Reconciliation [Line Items] Effective Income Tax Rate Reconciliation [Line Items] Contract with Customer, Asset, before Allowance for Credit Loss Contract with Customer, Asset, before Allowance for Credit Loss Prior service cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Accounts Receivable, Allowance for Credit Loss, Recovery Accounts Receivable, Allowance for Credit Loss, Recovery Operating Segments [Member] Operating Segments [Member] Regulatory Notes [Table] Regulatory Notes [Table] Regulatory Notes