Fair Value (Reconciliation Of Financial Instruments Classified As Level 3) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Forward Power Contracts Fair Value Disclosure	$ 14,294	$ 12,172
Total financial assets measured at fair value	19,234	22,945
Financial transmission rights	1,388	7,545
Investments, Fair Value Disclosure	3,552	3,228
Mutual Fund [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investments, Fair Value Disclosure	3,425	3,223
Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investments, Fair Value Disclosure	127	5
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total financial assets measured at fair value	3,552	3,228
Financial transmission rights	0	0
Investments, Fair Value Disclosure	3,552	3,228
Significant Observable Inputs (Level 2) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total financial assets measured at fair value	14,294	12,172
Financial transmission rights	0	0
Investments, Fair Value Disclosure	0	0
Unobservable Inputs (Level 3) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total financial assets measured at fair value	1,388	7,545
Financial transmission rights	1,388	7,545
Investments, Fair Value Disclosure	0	0
Derivative Financial Instruments, net Liabilities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	7,545	1,235
Issuances	3,624	15,338
Settlements	(9,781)	(9,028)
Ending balance	1,388	7,545
Indianapolis Power And Light Company
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total financial assets measured at fair value	1,388	7,545
Financial transmission rights	1,388	7,545
Indianapolis Power And Light Company | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total financial assets measured at fair value	0	0
Financial transmission rights	0	0
Indianapolis Power And Light Company | Significant Observable Inputs (Level 2) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total financial assets measured at fair value	0	0
Financial transmission rights	0	0
Indianapolis Power And Light Company | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Total financial assets measured at fair value	1,388	7,545
Financial transmission rights	1,388	7,545
Parent Company [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Forward Power Contracts Fair Value Disclosure	14,294	12,172
Total financial assets measured at fair value	17,846	15,400
Investments, Fair Value Disclosure	3,552	3,228
Parent Company [Member] | Mutual Fund [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investments, Fair Value Disclosure	3,425	3,223
Parent Company [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investments, Fair Value Disclosure	127	5
Parent Company [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Forward Power Contracts Fair Value Disclosure	0	0
Total financial assets measured at fair value	3,552	3,228
Investments, Fair Value Disclosure	3,552	3,228
Parent Company [Member] | Fair Value, Inputs, Level 1 [Member] | Mutual Fund [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investments, Fair Value Disclosure	3,425	3,223
Parent Company [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investments, Fair Value Disclosure	127	5
Parent Company [Member] | Significant Observable Inputs (Level 2) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Forward Power Contracts Fair Value Disclosure	14,294	12,172
Total financial assets measured at fair value	14,294	12,172
Investments, Fair Value Disclosure	0	0
Parent Company [Member] | Significant Observable Inputs (Level 2) [Member] | Mutual Fund [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investments, Fair Value Disclosure	0	0
Parent Company [Member] | Significant Observable Inputs (Level 2) [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investments, Fair Value Disclosure	0	0
Parent Company [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Forward Power Contracts Fair Value Disclosure	0	0
Total financial assets measured at fair value	0	0
Investments, Fair Value Disclosure		0
Parent Company [Member] | Unobservable Inputs (Level 3) [Member] | Mutual Fund [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investments, Fair Value Disclosure	0	0
Parent Company [Member] | Unobservable Inputs (Level 3) [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Investments, Fair Value Disclosure	$ 0	$ 0