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v3.23.1

Debt (Other Short-Term Borrowings) (Details) - USD ($) $ in Millions | 3 Months Ended
--- | ---
Mar. 31, 2023 | Mar. 31, 2022
Debt [Line Items] |  |
Maximum amount outstanding (based on daily outstanding balances) | $ 793 | $ 577
Average amount outstanding (based on daily outstanding balances) | $ 574 | $ 443
Weighted average interest rates | 4.80% | 0.30%
WPL [Member] |  |
Debt [Line Items] |  |
Maximum amount outstanding (based on daily outstanding balances) | $ 349 | $ 252
Average amount outstanding (based on daily outstanding balances) | $ 304 | $ 205
Weighted average interest rates | 4.80% | 0.30%

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