Overview and Summary of Significant Accounting Policies (Details) customer in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($) customer generating_station mi MW	Dec. 31, 2015 USD ($)
Debt Instrument [Line Items]
Distance of furthest customer from Indianapolis | mi	40
Number of generating stations | generating_station	4
Deferred financing costs	$ 23,500	$ 20,800
Adjustments for New Accounting Pronouncement [Member]
Debt Instrument [Line Items]
Deferred financing costs		(20,800)
Aes U.S. Investments [Member]
Debt Instrument [Line Items]
Ownership percentage by parent (percent)	82.35%
CDPQ [Member]
Debt Instrument [Line Items]
Ownership percentage by parent (percent)	17.65%
Ownership interest in parent company (percent)	15.00%
Percentage of direct and indirect ownership share of IPALCO	30.00%
AES U.S. Holdings, LLC [Member]
Debt Instrument [Line Items]
Ownership interest in parent company (percent)	85.00%
Indianapolis Power And Light Company [Member]
Debt Instrument [Line Items]
Number of customers | customer	480
Electric generation capability for winter, megawatts | MW	2,993
Electric generation capability for summer, megawatts | MW	2,878
Deferred financing costs	$ 18,043	13,703
Deferred Debits [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Deferred financing costs		$ 300