Regulatory Matters (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Regulatory Matters [Line Items]
Asset valuation charge for IPL's Lansing Generating Station	$ 0	$ 0	$ 60	$ 0
IPL [Member]
Regulatory Matters [Line Items]
Asset valuation charge for IPL's Lansing Generating Station	$ 0	$ 0	60	$ 0
October 2024 Through September 2025 Test Period Retail Electric [Member] | IPL [Member]
Regulatory Matters [Line Items]
Authorized increase (decrease) in final rates, amount			185
October 2024 Through September 2025 Test Period Retail Gas [Member] | IPL [Member]
Regulatory Matters [Line Items]
Authorized increase (decrease) in final rates, amount			$ 10