Fair Value (Summary Of Fair Value Assets And Liabilities Measured On A Recurring Basis, Level 3) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Entity Information [Line Items]
Financial transmission rights	$ 2,532	$ 4,393
Total financial assets measured at fair value	2,532	4,393
Other derivative liabilities	78	100
Total financial liabilities measured at fair value	78	100
Indianapolis Power And Light Company [Member]
Entity Information [Line Items]
Financial transmission rights	2,532	4,393
Total financial assets measured at fair value	2,532	4,393
Other derivative liabilities	78	100
Total financial liabilities measured at fair value	78	100
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Entity Information [Line Items]
Financial transmission rights	0	0
Total financial assets measured at fair value	0	0
Other derivative liabilities	0	0
Total financial liabilities measured at fair value	0	0
Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Indianapolis Power And Light Company [Member]
Entity Information [Line Items]
Financial transmission rights	0	0
Total financial assets measured at fair value	0	0
Other derivative liabilities	0	0
Total financial liabilities measured at fair value	0	0
Significant Observable Inputs (Level 2) [Member]
Entity Information [Line Items]
Financial transmission rights	0	0
Total financial assets measured at fair value	0	0
Other derivative liabilities	0	0
Total financial liabilities measured at fair value	0	0
Significant Observable Inputs (Level 2) [Member] | Indianapolis Power And Light Company [Member]
Entity Information [Line Items]
Financial transmission rights	0	0
Total financial assets measured at fair value	0	0
Other derivative liabilities	0	0
Total financial liabilities measured at fair value	0	0
Unobservable Inputs (Level 3) [Member]
Entity Information [Line Items]
Financial transmission rights	2,532	4,393
Total financial assets measured at fair value	2,532	4,393
Other derivative liabilities	78	100
Total financial liabilities measured at fair value	78	100
Unobservable Inputs (Level 3) [Member] | Indianapolis Power And Light Company [Member]
Entity Information [Line Items]
Financial transmission rights	2,532	4,393
Total financial assets measured at fair value	2,532	4,393
Other derivative liabilities	78	100
Total financial liabilities measured at fair value	$ 78	$ 100