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Receivables (Details of Accounts Receivable) (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Dec. 31, 2023
--- | --- | ---
Receivables [Line Items] |  |
Customer | $ 113 | $ 121
Unbilled utility revenues | 101 | 93
Deferred proceeds | 163 | 216
Other | 58 | 53
Allowance for expected credit losses | (8) | (8)
Accounts receivable, less allowance for expected credit losses | 427 | 475
IPL [Member] |  |
Receivables [Line Items] |  |
Customer | 0 | 0
Unbilled utility revenues | 0 | 0
Deferred proceeds | 163 | 216
Other | 29 | 26
Allowance for expected credit losses | 0 | 0
Accounts receivable, less allowance for expected credit losses | 192 | 242
WPL [Member] |  |
Receivables [Line Items] |  |
Customer | 98 | 110
Unbilled utility revenues | 101 | 93
Other | 29 | 24
Allowance for expected credit losses | (8) | (8)
Accounts receivable, less allowance for expected credit losses | $ 220 | $ 219

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