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Revenue Recognition (Allowance for Credit Losses) (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |
Allowance for Credit Loss | $ 22.9 | $ 23.9 | $ 23.5
Current period provisions | 39.8 | 36.0 |
Write-offs charged against allowance | (61.6) | (57.4) |
Recoveries of amounts previously written off | 20.8 | 21.8 |
Gas Distribution Operations |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |
Allowance for Credit Loss | 16.0 | 17.2 | 18.9
Current period provisions | 33.8 | 29.1 |
Write-offs charged against allowance | (55.4) | (52.1) |
Recoveries of amounts previously written off | 20.4 | 21.3 |
Electric Operations |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |
Allowance for Credit Loss | 6.1 | 5.9 | 3.8
Current period provisions | 6.0 | 6.9 |
Write-offs charged against allowance | (6.2) | (5.3) |
Recoveries of amounts previously written off | 0.4 | 0.5 |
Corporate and Other |  |  |
Financing Receivable, Allowance for Credit Loss [Line Items] |  |  |
Allowance for Credit Loss | 0.8 | 0.8 | $ 0.8
Current period provisions | 0.0 | 0.0 |
Write-offs charged against allowance | 0.0 | 0.0 |
Recoveries of amounts previously written off | $ 0.0 | $ 0.0 |

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