Schedule II - Valuation And Qualifying Accounts And Reserves (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 2,365	$ 2,498	$ 2,076
Charged to Income	5,854	4,122	4,273
Net Write-offs	5,389	4,255	3,851
Balance at End of Period	2,830	2,365	2,498
Indianapolis Power And Light Company [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	2,365	2,498	2,076
Charged to Income	5,854	4,122	4,273
Net Write-offs	5,389	4,255	3,851
Balance at End of Period	$ 2,830	$ 2,365	$ 2,498