| Overview and Summary of Significant Accounting Policies (Policy) | 12 Months Ended |
| Dec. 31, 2019 |
| Entity Information [Line Items] | |
| Property, Plant and Equipment, Policy [Policy Text Block] | Property, plant and equipment is stated at original cost as defined for regulatory purposes. The cost of additions to property, plant and equipment and replacements of retirement units of property are charged to plant accounts. Units of property replaced or abandoned in the ordinary course of business are retired from the plant accounts at cost; such amounts, less salvage, are charged to accumulated depreciation. Depreciation is computed by the straight-line method based on functional rates approved by the IURC and averaged 3.7% , 4.2% , and 4.1% during 2019 , 2018 and 2017 , respectively. Depreciation expense was $228.2 million , $235.2 million , and $209.8 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. "Depreciation and amortization" expense on the accompanying Consolidated Statements of Operations is presented net of regulatory deferrals of depreciation expense and also includes amortization of intangible assets and amortization of previously deferred regulatory costs. |
| Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] | The following table summarizes our accounts receivable balances at December 31: As of December 31, 2019 2018 (In Thousands) Accounts receivable, net Customer receivables $ 90,747 $ 91,426 Unbilled revenue 65,822 68,893 Amounts due from related parties 2,717 5,720 Other 3,857 4,341 Provision for uncollectible accounts (2,053 ) (2,821 ) Total accounts receivable, net $ 161,090 $ 167,559 |
| Inventory, Policy [Policy Text Block] | Inventories We maintain coal, fuel oil, materials and supplies inventories for use in the production of electricity. These inventories are accounted for at the lower of cost or net realizable value, using the average cost. The following table summarizes our inventories balances at December 31: As of December 31, 2019 2018 (In Thousands) Inventories Fuel $ 26,907 $ 32,457 Materials and supplies 56,662 67,211 Total inventories $ 83,569 $ 99,668 |
| Intangible Assets, Finite-Lived, Policy [Policy Text Block] | Intangible Assets Intangible assets primarily include capitalized software of $139.6 million and $129.7 million and its corresponding accumulated amortization of $74.7 million and $88.8 million , as of December 31, 2019 and 2018 , respectively. Amortization expense was $7.5 million , $5.5 million and $4.3 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. The estimated amortization expense of this capitalized software is approximately $50.0 million over the next 5 years ( $10.0 million in 2020, $10.0 million in 2021, $10.0 million in 2022, $10.0 million in 2023 and $10.0 million |
| Principles of Consolidation | Principles of Consolidation IPALCO’s consolidated financial statements are prepared in accordance with GAAP and in conjunction with the rules and regulations of the SEC. The consolidated financial statements include the accounts of IPALCO, its regulated utility subsidiary, IPL, and its unregulated subsidiary, Mid-America. All intercompany items have been eliminated in consolidation. Certain costs for shared resources amongst IPL and IPALCO, such as labor and benefits, are allocated to each entity based on allocation methodologies that management believes to be reasonable. We have evaluated subsequent events through the date this report is issued. |
| Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] | Financial Statement Presentation During 2018, we adopted a change in presentation on our Consolidated Balance Sheets and Consolidated Statements of Operations from a utility format to a traditional format. These changes combined or revised the order of certain balance sheet and income statement line items and resulted in the movement of certain immaterial balances within the Consolidated Statements of Operations and Consolidated Balance Sheets, but did not result in any material changes to the classification of any such amounts or have any impact on net assets or net income. Certain amounts from prior periods have been reclassified to conform to the current period presentation. |
| Use of Management Estimates | Use of Management Estimates The preparation of financial statements in conformity with GAAP requires that management make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. The reported amounts of revenues and expenses during the reporting period may also be affected by the estimates and assumptions management is required to make. Actual results may differ from those estimates. |
| Regulation | Regulatory Accounting The retail utility operations of IPL are subject to the jurisdiction of the IURC. IPL’s wholesale power transactions are subject to the jurisdiction of the FERC. These agencies regulate IPL’s utility business operations, tariffs, accounting, depreciation allowances, services, issuances of securities and the sale and acquisition of utility properties. The financial statements of IPL are based on GAAP, including the provisions of FASB ASC 980 “Regulated Operations,” which gives recognition to the ratemaking and accounting practices of these agencies. See also Note 2, “Regulatory Matters - Regulatory Assets and Liabilities” for a discussion of specific regulatory assets and liabilities. |
| Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] | Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents are stated at cost, which approximates fair value. All highly liquid short-term investments with original maturities of three months or less are considered cash equivalents. Restricted cash includes cash which is restricted as to withdrawal or usage. The nature of the restrictions includes restrictions imposed by agreements related to deposits held as collateral. The following table provides a summary of cash, cash equivalents and restricted cash amounts as shown on the Consolidated Statements of Cash Flows: As of December 31, 2019 2018 (In Thousands) Cash, cash equivalents and restricted cash Cash and cash equivalents $ 48,152 $ 33,199 Restricted cash 400 400 Total cash, cash equivalents and restricted cash $ 48,552 $ 33,599 |
| Revenues and Accounts Receivable | Revenues and Accounts Receivable Revenues related to the sale of energy are generally recognized when service is rendered or energy is delivered to customers. However, the determination of the energy sales to individual customers is based on the reading of their meters, which occurs on a systematic basis throughout the month. At the end of each month, amounts of energy delivered to certain customers since the date of the last meter reading are estimated and the corresponding unbilled revenue is accrued. In making its estimates of unbilled revenue, IPL uses complex models that consider various factors including daily generation volumes; known amounts of energy usage by nearly all residential, small commercial and industrial customers; estimated line losses; and estimated customer rates based on prior period billings. Given the use of these models, and that customers are billed on a monthly cycle, we believe it is unlikely that materially different results will occur in future periods when revenue is billed. An allowance for potential credit losses is maintained and amounts are written off when normal collection efforts have been exhausted. Our provision for doubtful accounts included in “Operating expenses - Operation and maintenance” on the accompanying Consolidated Statements of Operations was $5.5 million , $6.0 million and $ 5.9 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. IPL’s basic rates include a provision for fuel costs as established in IPL’s most recent rate proceeding, which last adjusted IPL’s rates in December 2018. IPL is permitted to recover actual costs of purchased power and fuel consumed, subject to certain restrictions. This is accomplished through quarterly FAC proceedings, in which IPL estimates the amount of fuel and purchased power costs in future periods. Through these proceedings, IPL is also permitted to recover, in future rates, underestimated fuel and purchased power costs from prior periods, subject to certain restrictions, and therefore the over or underestimated costs are deferred or accrued and amortized into fuel expense in the same period that IPL’s rates are adjusted. See also Note 2, “ Regulatory Matters ” for a discussion of other costs that IPL is permitted to recover through periodic rate adjustment proceedings and the status of current rate adjustment proceedings. In addition, we are one of many transmission system owner members of MISO, a regional transmission organization which maintains functional control over the combined transmission systems of its members and manages one of the largest energy markets in the U.S. See Note 13, " Revenue " for additional information of MISO sales and other revenue streams. The following table summarizes our accounts receivable balances at December 31: As of December 31, 2019 2018 (In Thousands) Accounts receivable, net Customer receivables $ 90,747 $ 91,426 Unbilled revenue 65,822 68,893 Amounts due from related parties 2,717 5,720 Other 3,857 4,341 Provision for uncollectible accounts (2,053 ) (2,821 ) Total accounts receivable, net $ 161,090 $ 167,559 |
| Contingencies | Contingencies IPALCO accrues for loss contingencies when the amount of the loss is probable and estimable. We are subject to various environmental regulations and are involved in certain legal proceedings. If IPL’s actual environmental and/or legal obligations are different from our estimates, the recognition of the actual amounts may have a material impact on our results of operations, financial condition and cash flows; although that has not been the case during the periods covered by this report. As of December 31, 2019 and 2018 , total loss contingencies accrued were $4.5 million and $4.6 million , respectively, which were included in “Accrued and Other Current Liabilities” on the accompanying Consolidated Balance Sheets. |
| Concentration of Risk | Concentrations of Risk Substantially all of IPL’s customers are located within the Indianapolis area. Approximately 69% of IPL’s employees are covered by collective bargaining agreements in two bargaining units: a physical unit and a clerical-technical unit. IPL’s contract with the physical unit expires on December 6, 2021 , and the contract with the clerical-technical unit expires February 13, 2023 . Additionally, IPL has long-term coal contracts with four suppliers, with about 33% of our existing coal under contract for the three-year period ending December 31, 2022 coming from one supplier. Substantially all of the coal is currently mined in the state of Indiana. |
| Allowance For Funds Used During Construction | Allowance For Funds Used During Construction In accordance with the Uniform System of Accounts prescribed by FERC, IPL capitalizes an allowance for the net cost of funds (interest on borrowed funds and a reasonable rate of return on equity funds) used for construction purposes during the period of construction with a corresponding credit to income. IPL capitalized amounts using pretax composite rates of 6.9% , 6.4% and 6.6% during 2019 , 2018 and 2017 |
| Derivatives | Financial Derivatives All derivatives are recognized as either assets or liabilities in the balance sheets and are measured at fair value. Changes in the fair value are recorded in earnings unless the derivative is designated as a cash flow hedge of a forecasted transaction or it qualifies for the normal purchases and sales exception. IPL has contracts involving the physical delivery of energy and fuel. Because these contracts qualify for the normal purchases and normal sales scope exception in ASC 815, IPL has elected to account for them as accrual contracts, which are not adjusted for changes in fair value. Additionally, we use interest rate hedges to manage the interest rate risk of our variable rate debt. We use cash flow hedge accounting when the hedge or a portion of the hedge is deemed to be highly effective, which results in changes in the fair value being recorded within accumulated other comprehensive income, a component of shareholders' equity. We have elected not to offset net derivative positions in the Financial Statements. Accordingly, we do not offset such derivative positions against the fair value of amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral under master netting agreements. See Note 5, “Derivative Instruments and Hedging Activities” for additional information. |
| Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] | Accumulated Other Comprehensive Income / (Loss) The changes in the components of Accumulated Other Comprehensive Income/(Loss) during the year ended December 31, 2019 are as follows: Gains and losses on cash flow hedges (In Thousands) Balance at January 1, 2019 $ — Other comprehensive loss (19,750 ) Balance at December 31, 2019 $ (19,750 ) |
| Impairment of Long-Lived Assets | Impairment of Long-lived Assets GAAP requires that we test long-lived assets for impairment when indicators of impairment exist. If an asset is deemed to be impaired, we are required to write down the asset to its fair value with a charge to current earnings. The net book value of our property, plant, and equipment was $4.1 billion as of December 31, 2019 and 2018 . We do not believe any of these assets are currently impaired. In making this assessment, we consider such factors as: the overall condition and generating and distribution capacity of the assets; the expected ability to recover additional expenditures in the assets; the anticipated demand and relative pricing of retail electricity in our service territory and wholesale electricity in the region; and the cost of fuel. |
| Income Taxes | Income Taxes Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of the existing assets and liabilities, and their respective income tax bases. The Company establishes a valuation allowance when it is more likely than not that all or a portion of a deferred tax asset will not be realized. The Company’s tax positions are evaluated under a more likely than not recognition threshold and measurement analysis before they are recognized for financial statement reporting. Uncertain tax positions have been classified as noncurrent income tax liabilities unless expected to be paid within one year. The Company’s policy for interest and penalties is to recognize interest and penalties as a component of the provision for income taxes in the Consolidated Statements of Operations. |
| Pension and Postretirement Benefits | Pension and Postretirement Benefits We recognize in our Consolidated Balance Sheets an asset or liability reflecting the funded status of pension and other postretirement plans with current-year changes in the funded status, that would otherwise be recognized in AOCI, recorded as a regulatory asset as this can be recovered through future rates. All plan assets are recorded at fair value. We follow the measurement date provisions of the accounting guidance, which require a year-end measurement date of plan assets and obligations for all defined benefit plans. We account for and disclose pension and postretirement benefits in accordance with the provisions of GAAP relating to the accounting for pension and other postretirement plans. These GAAP provisions require the use of assumptions, such as the discount rate for liabilities and long-term rate of return on assets, in determining the obligations, annual cost and funding requirements of the plans. Consistent with the requirements of ASC 715, we apply a disaggregated discount rate approach for determining service cost and interest cost for our defined benefit pension plans and postretirement plans. See Note 9, " Benefit Plans " for more information. |
| Repair and Maintenance Costs | Repair and Maintenance Costs Repair and maintenance costs are expensed as incurred. |
| Per Share Data | Per Share Data IPALCO is owned by AES U.S. Investments and CDPQ. IPALCO does not report earnings on a per-share basis. |
| New Accounting Pronouncements | New Accounting Pronouncements Adopted in 2019 The following table provides a brief description of recent accounting pronouncements that had an impact on the Company’s Financial Statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or did not have a material impact on the Company’s Financial Statements. New Accounting Standards Adopted ASU Number and Name Description Date of Adoption Effect on the Financial Statements upon adoption 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities The standard updates the hedge accounting model to expand the ability to hedge nonfinancial and financial risk components, reduce complexity, and ease certain documentation and assessment requirements. When facts and circumstances are the same as at the previous quantitative test, a subsequent quantitative effectiveness test is not required. The standard also eliminates the requirement to separately measure and report hedge ineffectiveness. For cash flow hedges, this means that the entire change in the fair value of a hedging instrument will be recorded in other comprehensive income and amounts deferred will be reclassified to earnings in the same income statement line as the hedged item. Transition method: modified retrospective with the cumulative effect adjustment recorded to the opening balance of retained earnings as of the initial application date. Prospective for presentation and disclosures. January 1, 2019 The adoption of this standard did not have a material impact on the Financial Statements. 2016-02, 2018-01, 2018-10, 2018-11, 2018-20, 2019-01, Leases (Topic 842) See discussion of the ASUs below. January 1, 2019 See impact upon adoption of the standard below. On January 1, 2019, the Company adopted ASC 842 Leases and its subsequent corresponding updates (“ASC 842”). Under this standard, lessees are required to recognize assets and liabilities for most leases on the balance sheet, and recognize expenses in a manner similar to the current accounting method. For lessors, the guidance modifies the lease classification criteria and the accounting for sales-type and direct financing leases. The guidance eliminates previous real estate-specific provisions. Under ASC 842, fewer of our contracts contain a lease. However, due to the elimination of the real estate-specific guidance and changes to certain lessor classification criteria, more leases qualify as sales-type leases and direct financing leases. Under these two models, a lessor derecognizes the asset and recognizes a lease receivable. According to ASC 842, the net investment in the lease includes the fair value of residual interest in the asset after the contract period as well as the present value of the fixed lease payments, but does not include any variable payments under the lease. Therefore, the net investment in the lease could be significantly different than the carrying amount of the underlying asset at lease commencement. In such circumstances, the difference between the initially recognized net investment in the lease and the carrying amount of the underlying asset is recognized as a gain/loss at lease commencement. During the course of adopting ASC 842, the Company applied various practical expedients including: • The package of practical expedients (applied to all leases) that allowed lessees and lessors not to reassess: a. whether any expired or existing contracts are or contain leases, b. lease classification for any expired or existing leases, and c. whether initial direct costs for any expired or existing leases qualify for capitalization under ASC 842. • The transition practical expedient related to land easements, allowing us to carry forward our accounting treatment for land easements on existing agreements, and • The transition practical expedient for lessees that allowed businesses to not separate lease and non-lease components. The Company applied the practical expedient to all classes of underlying assets when valuing right-of-use assets and lease liabilities. Contracts where the Company is the lessor were separated between the lease and non-lease components. The Company applied the modified retrospective method of adoption and elected to continue to apply the guidance in ASC 840 Leases to the comparative periods presented in the year of adoption. Under this transition method, the Company applied the transition provisions starting at the date of adoption. The adoption of ASC 842 did not have a material impact on our Financial Statements. |
| Indianapolis Power And Light Company | |
| Entity Information [Line Items] | |
| Property, Plant and Equipment, Policy [Policy Text Block] | Property, Plant and Equipment Property, plant and equipment is stated at original cost as defined for regulatory purposes. The cost of additions to property, plant and equipment and replacements of retirement units of property are charged to plant accounts. Units of property replaced or abandoned in the ordinary course of business are retired from the plant accounts at cost; such amounts, less salvage, are charged to accumulated depreciation. Depreciation is computed by the straight-line method based on functional rates approved by the IURC and averaged 3.7% , 4.2% , and 4.1% during 2019 , 2018 and 2017 , respectively. Depreciation expense was $228.2 million , $235.2 million , and $209.8 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. "Depreciation and amortization" expense on the accompanying Consolidated Statements of Operations is presented net of regulatory deferrals of depreciation expense and also includes amortization of intangible assets and amortization of previously deferred regulatory costs. |
| Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] | The following table summarizes our accounts receivable balances at December 31: As of December 31, 2019 2018 (In Thousands) Accounts receivable, net Customer receivables $ 90,747 $ 91,426 Unbilled revenue 65,822 68,893 Amounts due from related parties 2,992 6,030 Other 3,857 4,341 Provision for uncollectible accounts (2,053 ) (2,821 ) Total accounts receivable, net $ 161,365 $ 167,869 |
| Intangible Assets, Finite-Lived, Policy [Policy Text Block] | Intangible Assets Intangible assets primarily include capitalized software of $139.6 million and $129.7 million and its corresponding accumulated amortization of $74.7 million and $88.8 million , as of December 31, 2019 and 2018 , respectively. Amortization expense was $7.5 million , $5.5 million and $4.3 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. The estimated amortization expense of this capitalized software is approximately $50.0 million over the next 5 years ( $10.0 million in 2020, $10.0 million in 2021, $10.0 million in 2022, $10.0 million in 2023 and $10.0 million in 2024). |
| Principles of Consolidation | Principles of Consolidation IPL’s consolidated financial statements are prepared in accordance with GAAP and in conjunction with the rules and regulations of the SEC. The consolidated financial statements include the accounts of IPL and its unregulated subsidiary, IPL Funding Corporation, which was dissolved in 2018 and was immaterial to the consolidated financial statements in the periods covered by this report. All intercompany items have been eliminated in consolidation. Certain costs for shared resources amongst IPL and IPALCO, such as labor and benefits, are allocated to each entity based on allocation methodologies that management believes to be reasonable. We have evaluated subsequent events through the date this report is issued. |
| Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] | Financial Statement Presentation |
| Use of Management Estimates | Use of Management Estimates The preparation of financial statements in conformity with GAAP requires that management make certain estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. The reported amounts of revenues and expenses during the reporting period may also be affected by the estimates and assumptions management is required to make. Actual results may differ from those estimates. |
| Regulation | Regulatory Accounting The retail utility operations of IPL are subject to the jurisdiction of the IURC. IPL’s wholesale power transactions are subject to the jurisdiction of the FERC. These agencies regulate IPL’s utility business operations, tariffs, accounting, depreciation allowances, services, issuances of securities and the sale and acquisition of utility properties. The financial statements of IPL are based on GAAP, including the provisions of FASB ASC 980 “Regulated Operations,” which gives recognition to the ratemaking and accounting practices of these agencies. See also Note 2, “Regulatory Matters - Regulatory Assets and Liabilities” for a discussion of specific regulatory assets and liabilities. |
| Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] | Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents are stated at cost, which approximates fair value. All highly liquid short-term investments with original maturities of three months or less are considered cash equivalents. Restricted cash includes cash which is restricted as to withdrawal or usage. The nature of the restrictions includes restrictions imposed by agreements related to deposits held as collateral. The following table provides a summary of cash, cash equivalents and restricted cash amounts as shown on the Consolidated Statements of Cash Flows: As of December 31, 2019 2018 (In Thousands) Cash, cash equivalents and restricted cash Cash and cash equivalents $ 42,189 $ 26,834 Restricted cash 400 400 Total cash, cash equivalents and restricted cash $ 42,589 $ 27,234 |
| Revenues and Accounts Receivable | Revenues and Accounts Receivable Revenues related to the sale of energy are generally recognized when service is rendered or energy is delivered to customers. However, the determination of the energy sales to individual customers is based on the reading of their meters, which occurs on a systematic basis throughout the month. At the end of each month, amounts of energy delivered to certain customers since the date of the last meter reading are estimated and the corresponding unbilled revenue is accrued. In making its estimates of unbilled revenue, IPL uses complex models that consider various factors including daily generation volumes; known amounts of energy usage by nearly all residential, small commercial and industrial customers; estimated line losses; and estimated customer rates based on prior period billings. Given the use of these models, and that customers are billed on a monthly cycle, we believe it is unlikely that materially different results will occur in future periods when revenue is billed. An allowance for potential credit losses is maintained and amounts are written off when normal collection efforts have been exhausted. IPL’s provision for doubtful accounts included in “ Operating expenses - Operation and maintenance” on the accompanying Consolidated Statements of Operations was $5.5 million , $6.0 million and $5.9 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. IPL’s basic rates include a provision for fuel costs as established in IPL’s most recent rate proceeding, which last adjusted IPL’s rates in December 2018. IPL is permitted to recover actual costs of purchased power and fuel consumed, subject to certain restrictions. This is accomplished through quarterly FAC proceedings, in which IPL estimates the amount of fuel and purchased power costs in future periods. Through these proceedings, IPL is also permitted to recover, in future rates, underestimated fuel and purchased power costs from prior periods, subject to certain restrictions, and therefore the over or underestimated costs are deferred or accrued and amortized into fuel expense in the same period that IPL’s rates are adjusted. See also Note 2, “ Regulatory Matters ” for a discussion of other costs that IPL is permitted to recover through periodic rate adjustment proceedings and the status of current rate adjustment proceedings. In addition, IPL is one of many transmission system owner members of MISO, a regional transmission organization which maintains functional control over the combined transmission systems of its members and manages one of the largest energy markets in the U.S. See Note 13, " Revenue " for additional information of MISO sales and other revenue streams. The following table summarizes our accounts receivable balances at December 31: As of December 31, 2019 2018 (In Thousands) Accounts receivable, net Customer receivables $ 90,747 $ 91,426 Unbilled revenue 65,822 68,893 Amounts due from related parties 2,992 6,030 Other 3,857 4,341 Provision for uncollectible accounts (2,053 ) (2,821 ) Total accounts receivable, net $ 161,365 $ 167,869 |
| Contingencies | Contingencies IPL accrues for loss contingencies when the amount of the loss is probable and estimable. IPL is subject to various environmental regulations and is involved in certain legal proceedings. If IPL’s actual environmental and/or legal obligations are different from our estimates, the recognition of the actual amounts may have a material impact on our results of operations, financial condition and cash flows; although that has not been the case during the periods covered by this report. As of December 31, 2019 and 2018 , total loss contingencies accrued were $4.5 million and $4.6 million , respectively, which were included in “ Accrued and Other Current Liabilities” on the accompanying Consolidated Balance Sheets. |
| Concentration of Risk | Concentrations of Risk Substantially all of IPL’s customers are located within the Indianapolis area. Approximately 69% of IPL’s employees are covered by collective bargaining agreements in two bargaining units: a physical unit and a clerical-technical unit. IPL’s contract with the physical unit expires on December 6, 2021 , and the contract with the clerical-technical unit expires February 13, 2023 . Additionally, IPL has long-term coal contracts with four suppliers, with about 33% of our existing coal under contract for the three-year period ending December 31, 2022 coming from one supplier. Substantially all of the coal is currently mined in the state of Indiana. |
| Allowance For Funds Used During Construction | Allowance For Funds Used During Construction |
| Derivatives | Derivatives All derivatives are recognized as either assets or liabilities in the balance sheets and are measured at fair value. Changes in the fair value are recorded in earnings unless the derivative is designated as a cash flow hedge of a forecasted transaction or it qualifies for the normal purchases and sales exception. IPL has contracts involving the physical delivery of energy and fuel. Because these contracts qualify for the normal purchases and normal sales scope exception in ASC 815, IPL has elected to account for them as accrual contracts, which are not adjusted for changes in fair value. |
| Impairment of Long-Lived Assets | Impairment of Long-lived Assets GAAP requires that IPL test long-lived assets for impairment when indicators of impairment exist. If an asset is deemed to be impaired, IPL is required to write down the asset to its fair value with a charge to current earnings. The net book value of IPL’s property, plant, and equipment was $4.1 billion as of December 31, 2019 and 2018 . IPL does not believe any of these assets are currently impaired. In making this assessment, IPL considers such factors as: the overall condition and generating and distribution capacity of the assets; the expected ability to recover additional expenditures in the assets; the anticipated demand and relative pricing of retail electricity in its service territory and wholesale electricity in the region; and the cost of fuel. |
| Income Taxes | Income Taxes Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of the existing assets and liabilities, and their respective income tax bases. IPL establishes a valuation allowance when it is more likely than not that all or a portion of a deferred tax asset will not be realized. IPL’s tax positions are evaluated under a more likely than not recognition threshold and measurement analysis before they are recognized for financial statement reporting. Uncertain tax positions have been classified as noncurrent income tax liabilities unless expected to be paid within one year. IPL’s policy for interest and penalties is to recognize interest and penalties as a component of the provision for income taxes in the Consolidated Statements of Operations. |
| Pension and Postretirement Benefits | Pension and Postretirement Benefits IPL recognizes in its Consolidated Balance Sheets an asset or liability reflecting the funded status of pension and other postretirement plans with current-year changes in the funded status, that would otherwise be recognized in AOCI, recorded as a regulatory asset as this can be recovered through future rates. All plan assets are recorded at fair value. IPL follows the measurement date provisions of the accounting guidance, which require a year-end measurement date of plan assets and obligations for all defined benefit plans. IPL accounts for and discloses pension and postretirement benefits in accordance with the provisions of GAAP relating to the accounting for pension and other postretirement plans. These GAAP provisions require the use of assumptions, such as the discount rate for liabilities and long-term rate of return on assets, in determining the obligations, annual cost and funding requirements of the plans. Consistent with the requirements of ASC 715, IPL applies a disaggregated discount rate approach for determining service cost and interest cost for its defined benefit pension plans and postretirement plans. |
| Repair and Maintenance Costs | Repair and Maintenance Costs Repair and maintenance costs are expensed as incurred. |
| Per Share Data | Per Share Data IPALCO owns all of the outstanding common stock of IPL. IPL does not report earnings on a per-share basis. |
| New Accounting Pronouncements | |
