Regulatory Matters (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Regulatory Matters [Line Items]
Asset valuation charge for IPL's Lansing Generating Station	$ 0	$ 0	$ 0	$ 60
IPL [Member]
Regulatory Matters [Line Items]
Asset valuation charge for IPL's Lansing Generating Station	$ 0	$ 0	$ 0	$ 60

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (b)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 942
-SubTopic 10
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480095/942-10-S50-1

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 942
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480035/942-10-S99-6

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482130/360-10-45-4

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration