Schedule I - Condensed Financial Information Of Registrant (Narrative) (Details) $ in Thousands					12 Months Ended
	Jun. 01, 2016 USD ($)	Mar. 01, 2016 USD ($) shares	Apr. 01, 2015 USD ($) shares	Feb. 11, 2015 USD ($) item shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Condensed Financial Statements, Captions [Line Items]
Common shares issued | shares				100
Ownership percentage by parent					82.35%
Common stock issued and sold to CDPQ						$ 134,276	$ 214,366
Proceeds from Contributed Capital					$ 0	78,738	0
Ipalco Enterprises, Inc. [Member]
Condensed Financial Statements, Captions [Line Items]
Equity contributions from AES	$ 64,800				$ 0	78,738	$ 0
Additional investment through agreement				$ 349,000
Direct and indirect ownership percentage				30.00%
Increase in ownership percentage after investment				17.65%
Ownership percentage by parent					82.35%
Number of board members | item				11
Common stock issued and sold to CDPQ						$ 134,276
AES U.S. Investments [Member]
Condensed Financial Statements, Captions [Line Items]
Number of board members | item				9
CDPQ [Member]
Condensed Financial Statements, Captions [Line Items]
Minimum ownership percentage to retain board members				5.00%
Number of board members | item				2
Percentage Of Direct And Indirect Ownership Share Of IPALCO					30.00%
Shareholder [Member]
Condensed Financial Statements, Captions [Line Items]
Proceeds from Contributed Capital	$ 13,900
Common Stock [Member]
Condensed Financial Statements, Captions [Line Items]
Common stock issued and sold to CDPQ (shares) | shares		7,403,213
Common stock issued and sold to CDPQ		$ 134,300
Common Stock [Member] | Ipalco Enterprises, Inc. [Member]
Condensed Financial Statements, Captions [Line Items]
Common stock issued and sold to CDPQ (shares) | shares			11,818,828
Common stock issued and sold to CDPQ			$ 214,400