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Debt (Credit Facilities) (Details) $ in Millions | Jun. 30, 2022 USD ($)
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Debt [Line Items] |
Amount outstanding | $ 399
Weighted average interest rates | 1.80%
Available credit facility capacity | $ 601
IPL [Member] |
Debt [Line Items] |
Amount outstanding | 0
Available credit facility capacity | 250
WPL [Member] |
Debt [Line Items] |
Amount outstanding | $ 222
Weighted average interest rates | 1.70%
Available credit facility capacity | $ 78

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