Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Self-insured retention per occurrence	$ 5.0
Insurance expense	4.3	$ 3.1	$ 3.1
Prepaid insurance	2.0	1.6
Health coverage expense	20.2	21.5	24.9
Income taxes receivable	23.7	13.8
Deferred Compensation Arrangement with Individual, Compensation Expense	0.3	0.5	0.8
Related Party Transactions, Total Purchases from related party over the life of project	474.9
Billings from related party	3.0	5.7	2.4
Service Company [Member]
Related Party Transaction [Line Items]
Costs incurred by related party	42.0	44.5	34.4
Prepaid balance to related party	8.4
Ipalco Enterprises, Inc. [Member]
Related Party Transaction [Line Items]
Costs incurred by related party	9.7	10.1	10.7
Indianapolis Power And Light Company
Related Party Transaction [Line Items]
Self-insured retention per occurrence	5.0
Insurance expense	4.3	3.1	3.1
Prepaid insurance	2.0	1.6
Health coverage expense	20.2	21.5	24.9
Income taxes receivable	23.1	13.5
Deferred Compensation Arrangement with Individual, Compensation Expense	0.3	0.5	0.8
Costs incurred by related party	9.7	10.1	10.7
Prepaid balance to related party	8.4
Related Party Transactions, Total Purchases from related party over the life of project	474.9
Billings from related party	3.0	5.7	2.4
Indianapolis Power And Light Company \| Service Company [Member]
Related Party Transaction [Line Items]
Costs incurred by related party	$ 41.8	$ 44.1	$ 34.1

Prepaid Expense to Related Party

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Related Party Transactions,Total Purchases from related party over the life of project

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Self-Insured Retention Per Occurrence

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Costs of sales and operating expenses for the period incurred from transactions with related parties.

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The compensation expense recognized during the period pertaining to the deferred compensation arrangement.

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The expense in the period incurred with respect to protection provided by insurance entities against risks other than risks associated with production (which are allocated to cost of sales).

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Carrying amount as of the balance sheet date of income taxes previously overpaid to tax authorities (such as U.S. Federal, state and local tax authorities) representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes. Also called income tax refund receivable.

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Amount of asset related to consideration paid in advance for insurance that provides economic benefits within a future period of one year or the normal operating cycle, if longer.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Purchases during the period (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

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