Equity (Narrative) (Details) $ in Thousands					12 Months Ended
	Jun. 01, 2016 USD ($)	Mar. 01, 2016 USD ($) shares	Apr. 01, 2015 USD ($) shares	Feb. 11, 2015 item shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares
Class of Stock [Line Items]
Common shares issued				100
Ownership percentage by parent					82.35%
Proceeds from Contributed Capital | $					$ 0	$ 78,738	$ 0
Common stock issued and sold to CDPQ | $						$ 134,276	$ 214,366
Debt to capitalization ratio					0.65
Debt to Capitalization Ratio, Maximum					1
Preferred stock outstanding					591,353
Change in capital stock					0	0	0
5.65% Series Preferred Stock [Member]
Class of Stock [Line Items]
Dividend rate on preferred stock					5.65%
Preferred stock issued					500,000
Preferred stock outstanding					500,000
Nonredeemable Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock outstanding					91,353
Indianapolis Power And Light Company [Member]
Class of Stock [Line Items]
Equity contributions from AES | $	$ 64,800				$ 0	$ 213,014	$ 214,364
Proceeds from Contributed Capital | $	13,900
Debt to capitalization ratio					0.65
Debt to Capitalization Ratio, Maximum					1
Total preferred stock dividends declared | $					$ 3,213	$ 3,213	$ 3,213
Preferred stock outstanding					591,353
Change in capital stock					0	0	0
Indianapolis Power And Light Company [Member] | 5.65% Series Preferred Stock [Member]
Class of Stock [Line Items]
Dividend rate on preferred stock					5.65%
Preferred stock issued					500,000
Preferred stock outstanding					500,000
Indianapolis Power And Light Company [Member] | Nonredeemable Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock outstanding					91,353
Shareholder [Member]
Class of Stock [Line Items]
Proceeds from Contributed Capital | $	$ 13,900
AES U.S. Investments [Member]
Class of Stock [Line Items]
Number of board members | item				9
AES U.S. Holdings, LLC [Member]
Class of Stock [Line Items]
Ownership Interest in Parent Company, Percent					85.00%
CDPQ [Member]
Class of Stock [Line Items]
Ownership Interest in Parent Company, Percent					15.00%
Number of board members | item				2
Minimum ownership percentage to retain board members				5.00%
Percentage Of Direct And Indirect Ownership Share Of IPALCO					30.00%
Minimum [Member]
Class of Stock [Line Items]
Dividend rate on preferred stock					4.00%
Minimum [Member] | Indianapolis Power And Light Company [Member]
Class of Stock [Line Items]
Dividend rate on preferred stock					4.00%
Maximum [Member]
Class of Stock [Line Items]
Dividend rate on preferred stock					5.65%
Maximum [Member] | Indianapolis Power And Light Company [Member]
Class of Stock [Line Items]
Dividend rate on preferred stock					5.65%
Common Stock [Member]
Class of Stock [Line Items]
Common stock issued and sold to CDPQ (shares)		7,403,213
Common stock issued and sold to CDPQ | $		$ 134,300
Common Stock [Member] | Indianapolis Power And Light Company [Member]
Class of Stock [Line Items]
Common stock issued and sold to CDPQ (shares)		7,403,213	11,818,828
Common stock issued and sold to CDPQ | $		$ 134,300	$ 214,400