Debt (Schedule Long-Term Indebtedness) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 01, 2016	May 31, 2016	Sep. 30, 2015	Jun. 30, 2015
Debt Instrument [Line Items]
Unamortized discount - net	$ (6,900)	$ (6,800)
Debt Issuance Costs, Net	(24,400)	(22,200)
Long-term debt	2,477,538	2,499,490
Current portion of long-term debt	0	24,650
Long-term debt	2,477,538	2,474,840
First Mortgage Bond 4.55% Due December 2024 [Member]
Debt Instrument [Line Items]
Debt, stated interest rate			3.125%
Ipalco Enterprises, Inc. [Member]
Debt Instrument [Line Items]
Unamortized discount - net	(534)	(273)
Debt Issuance Costs, Net	(7,863)	(5,018)
Long-term debt	801,603	799,709
Current portion of long-term debt	0	0
Long-term debt	$ 801,603	799,709
Ipalco Enterprises, Inc. [Member] | 7.25% Senior Secured Notes [Member]
Debt Instrument [Line Items]
Long-term debt						$ 33,500
Debt, stated interest rate	7.25%
Ipalco Enterprises, Inc. [Member] | 5.00% Senior Secured Notes [Member]
Debt Instrument [Line Items]
Long-term debt	$ 0	400,000
Debt, stated interest rate	5.00%
Debt due date	May 01, 2018
Ipalco Enterprises, Inc. [Member] | 3.45% Senior Secured Notes [Member]
Debt Instrument [Line Items]
Long-term debt	$ 405,000	405,000
Debt, stated interest rate	3.45%
Debt due date	Jul. 01, 2020
Ipalco Enterprises, Inc. [Member] | Three Point Seven Zero Percent Senior Secured Notes [Domain]
Debt Instrument [Line Items]
First mortgage bonds	$ 405,000
Long-term debt	$ 405,000	0
Debt, stated interest rate	3.70%
Debt due date	Sep. 01, 2024
Indianapolis Power And Light Company [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 1,586,279	1,610,237
Unamortized discount - net	(6,353)	(6,477)
Debt Issuance Costs, Net	(16,500)	(17,200)
Unsecured Debt	89,656	89,544
Long-term debt	1,675,935	1,699,781
Current portion of long-term debt	0	24,650
Long-term debt	$ 1,675,935	1,675,131
Indianapolis Power And Light Company [Member] | First Mortgage Bond 4.90% Due January 2016 [Member]
Debt Instrument [Line Items]
Debt, stated interest rate	4.90%
Indianapolis Power And Light Company [Member] | First Mortgage Bond 5.40% Due August 2017 [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 0	24,650
Debt, stated interest rate	5.40%
Debt due date	Aug. 01, 2017
Indianapolis Power And Light Company [Member] | First Mortgage Bond 3.875% Due August 2021 [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 55,000	55,000
Debt, stated interest rate	3.875%
Debt due date	Aug. 01, 2021
Indianapolis Power And Light Company [Member] | First Mortgage Bond 3.875% Due August 2021 [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 40,000	40,000
Debt, stated interest rate	3.875%
Debt due date	Aug. 01, 2021
Indianapolis Power And Light Company [Member] | First Mortgage Bond 4.55% Due December 2024 [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 40,000	40,000
Debt, stated interest rate	4.55%		3.125%
Debt due date	Dec. 01, 2024
Indianapolis Power And Light Company [Member] | First Mortgage Bond 6.60% Due January 2034 [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 100,000	100,000
Debt, stated interest rate	6.60%
Debt due date	Jan. 01, 2034
Indianapolis Power And Light Company [Member] | First Mortgage Bond 6.05% Due October 2036 [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 158,800	158,800
Debt, stated interest rate	6.05%
Debt due date	Oct. 01, 2036
Indianapolis Power And Light Company [Member] | First Mortgage Bond 6.60% Due June 2037 [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 165,000	165,000
Debt, stated interest rate	6.60%
Debt due date	Jun. 01, 2037
Indianapolis Power And Light Company [Member] | First Mortgage Bond 4.875% Due November 2041 [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 140,000	140,000
Debt, stated interest rate	4.875%
Debt due date	Nov. 01, 2041
Indianapolis Power And Light Company [Member] | First Mortgage Bond 4.65% Due June 2043 [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 170,000	170,000
Debt, stated interest rate	4.65%
Debt due date	Jun. 01, 2043
Indianapolis Power And Light Company [Member] | First Mortgage Bond 4.70% Due September 2045 [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 130,000	130,000
Debt, stated interest rate	4.50%				4.70%
Debt due date	Jun. 01, 2044
Indianapolis Power And Light Company [Member] | First Mortgage Bond Nineteen [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 260,000	260,000
Debt, stated interest rate	4.70%
Debt due date	Sep. 01, 2045
Indianapolis Power And Light Company [Member] | FMB Twenty [Member]
Debt Instrument [Line Items]
First mortgage bonds	$ 350,000	350,000
Debt, stated interest rate	4.05%			4.05%
Debt due date	May 01, 2046
Indianapolis Power And Light Company [Member] | Environmental Facilities Refunding Revenue Notes, Series 2015A [Member]
Debt Instrument [Line Items]
Unsecured Debt	$ 30,000	30,000
Debt due date	Dec. 01, 2020
Indianapolis Power And Light Company [Member] | Environmental Facilities Refunding Revenue Notes, Series 2015B [Member]
Debt Instrument [Line Items]
Unsecured Debt	$ 60,000	60,000
Debt due date	Dec. 01, 2020
Secured Debt [Member] | Indianapolis Power And Light Company [Member]
Debt Instrument [Line Items]
Unamortized discount - net	$ (6,353)
Debt Issuance Costs, Net	(16,168)	(16,736)
Unsecured Debt [Member] | Indianapolis Power And Light Company [Member]
Debt Instrument [Line Items]
Debt Issuance Costs, Net	$ (344)	$ (456)