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Derivative Instruments (Notional Amounts Of Derivative Instruments) (Details) - Commodity Contracts [Member] gal in Thousands	9 Months Ended
	Sep. 30, 2025 Dekatherms MWh gal
Electricity (MWhs) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	1,689
Electricity (MWhs) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	563
Electricity (MWhs) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	1,126
FTRs (MWhs) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	17,992
FTRs (MWhs) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	7,143
FTRs (MWhs) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in MWhs)	10,849
Natural Gas (Dths) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	136,910
Natural Gas (Dths) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	56,355
Natural Gas (Dths) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Dths) | Dekatherms	80,555
Diesel Fuel (Gallons) [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	630
Diesel Fuel (Gallons) [Member] | IPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	0
Diesel Fuel (Gallons) [Member] | WPL [Member]
Notional Amount of Derivatives [Line Items]
Notional unit amount of derivatives (in Gallons) | gal	630

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- Definition

Notional Amount of Derivatives [Line Items]

+ References

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- Definition

Nominal number of units used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-8A

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1B

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-1A

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 40
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480237/815-40-50-5

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1I
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1I

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 505
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481112/505-10-50-18

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Nominal energy measure used to calculate payments on a derivative instrument.

+ References

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- Definition

Nominal volume used to calculate payments on a derivative instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 181
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480401/815-10-55-181

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