Property, Plant and Equipment (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Public Utility, Property, Plant and Equipment [Line Items]
Revisions to cash flow and timing estimates	$ 78,153	$ 54,811
Direct first mortgage lien	1,713,800
Non-contractually required removal costs of utility plant in service	788,300	761,100
Contractually required removal costs of utility plant in service	204,200	129,500
Indianapolis Power And Light Company
Public Utility, Property, Plant and Equipment [Line Items]
Revisions to cash flow and timing estimates	78,153	54,811
Direct first mortgage lien	1,713,800
Non-contractually required removal costs of utility plant in service	788,300	761,100
Contractually required removal costs of utility plant in service	$ 204,200	$ 129,500