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v3.25.1

BUSINESS SEGMENTS - Business Segments (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Dec. 31, 2024
Business Segments [Line Items] |  |  |
Other | $ 1.5 | $ 1.3 |
Total Operating Revenue | 400.2 | 403.3 |
Net Income (Loss) Attributable to ALLETE | 56.1 | 50.7 |
Assets | 6,866.3 | 6,604.6 | $ 6,754.3
Operating Segments |  |  |
Business Segments [Line Items] |  |  |
Other | 1.5 | 1.3 |
Total Operating Revenue | 370.7 | 374.4 |
Net Income (Loss) Attributable to ALLETE | 55.0 | 52.0 |
Assets | 6,375.8 | 6,221.0 |
Corporate and Other |  |  |
Business Segments [Line Items] |  |  |
Other | 0.0 | 0.0 |
Total Operating Revenue | 29.5 | 28.9 |
Net Income (Loss) Attributable to ALLETE | 1.1 | (1.3) |
Assets | 490.5 | 383.6 |
Regulated Operations |  |  |
Business Segments [Line Items] |  |  |
Total Operating Revenue | 332.8 | 338.3 |
Net Income (Loss) Attributable to ALLETE | 38.4 | 44.2 |
Assets | 4,560.2 |  | 4,489.4
Regulated Operations | Operating Segments |  |  |
Business Segments [Line Items] |  |  |
Other | 0.0 | 0.0 |
Total Operating Revenue | 332.8 | 338.3 |
Net Income (Loss) Attributable to ALLETE | 38.4 | 44.2 |
Assets | 4,560.2 | 4,345.1 |
Regulated Operations | Residential |  |  |
Business Segments [Line Items] |  |  |
Operating Revenue | 56.4 | 51.5 |
Regulated Operations | Commercial |  |  |
Business Segments [Line Items] |  |  |
Operating Revenue | 51.7 | 49.7 |
Regulated Operations | Municipal |  |  |
Business Segments [Line Items] |  |  |
Operating Revenue | 9.6 | 9.0 |
Regulated Operations | Industrial |  |  |
Business Segments [Line Items] |  |  |
Operating Revenue | 139.9 | 159.5 |
Regulated Operations | Other Power Suppliers |  |  |
Business Segments [Line Items] |  |  |
Operating Revenue | 47.1 | 40.0 |
Regulated Operations | Other |  |  |
Business Segments [Line Items] |  |  |
Operating Revenue | 28.1 | 28.6 |
ALLETE Clean Energy |  |  |
Business Segments [Line Items] |  |  |
Total Operating Revenue | 16.5 | 19.1 |
Net Income (Loss) Attributable to ALLETE | 7.4 | 3.8 |
Assets | 1,464.2 |  | 1,477.4
ALLETE Clean Energy | Operating Segments |  |  |
Business Segments [Line Items] |  |  |
Other | 1.5 | 1.3 |
Total Operating Revenue | 16.5 | 19.1 |
Net Income (Loss) Attributable to ALLETE | 7.4 | 3.8 |
Assets | 1,464.2 | 1,580.0 |
ALLETE Clean Energy | Long-term PSA |  |  |
Business Segments [Line Items] |  |  |
Operating Revenue | 15.0 | 17.8 |
ALLETE Clean Energy | Other |  |  |
Business Segments [Line Items] |  |  |
Other | 1.5 | 1.3 |
New Energy |  |  |
Business Segments [Line Items] |  |  |
Total Operating Revenue | 21.4 | 17.0 |
Net Income (Loss) Attributable to ALLETE | 9.2 | 4.0 |
Assets | 351.4 |  | 335.7
New Energy | Operating Segments |  |  |
Business Segments [Line Items] |  |  |
Other | 0.0 | 0.0 |
Total Operating Revenue | 21.4 | 17.0 |
Net Income (Loss) Attributable to ALLETE | 9.2 | 4.0 |
Assets | 351.4 | 295.9 |
New Energy | Sale of Renewable Development Projects |  |  |
Business Segments [Line Items] |  |  |
Operating Revenue | 18.2 | 13.9 |
New Energy | Other |  |  |
Business Segments [Line Items] |  |  |
Operating Revenue | 3.2 | 3.1 |
Corporate and Other |  |  |
Business Segments [Line Items] |  |  |
Total Operating Revenue | 29.5 | 28.9 |
Net Income (Loss) Attributable to ALLETE | 1.1 | (1.3) |
Assets | 490.5 |  | $ 451.8
Corporate and Other | Other |  |  |
Business Segments [Line Items] |  |  |
Operating Revenue | 3.4 | 3.5 |
Corporate and Other | Long-term Contract |  |  |
Business Segments [Line Items] |  |  |
Operating Revenue | $ 26.1 | $ 25.4 |

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