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Property, Plant and Equipment (Narrative) (Details) | 9 Months Ended
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Sep. 30, 2024 USD ($) lease_renewal_period_option MW
IPL [Member] |
Property, Plant and Equipment [Line Items] |
Electric capacity of solar project | MW | 400
Construction project cost target, exceedance | $ 1,837.5
Construction project cost target, original | $ 1,650
Solar project cost return on equity, percentage | 10.25%
WPL [Member] |
Property, Plant and Equipment [Line Items] |
Electric capacity of solar project | MW | 1,100
Construction project cost target, exceedance | $ 195,000,000
WPL [Member] | Sheboygan Falls Energy Facility |
Property, Plant and Equipment [Line Items] |
Financing lease, lease renewal periods remaining | lease_renewal_period_option | 0
WPL [Member] | West Riverside Energy Center [Member] |
Property, Plant and Equipment [Line Items] |
Ownership interest, percent | 56.60%
Electric Generation | WPL [Member] | Edgewater Unit 5 |
Property, Plant and Equipment [Line Items] |
Net book value, Edgewater Unit 5 | $ 493,000,000
Utility electric generation plant in service, Edgewater Unit 5 | $ 794,000,000

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