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v3.25.3

BUSINESS SEGMENTS - Business Segments (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2025 | Sep. 30, 2024
Business Segments [Line Items] |  |  |  |
Other | $ 1.5 | $ 1.3 | $ 4.4 | $ 3.8
Total Operating Revenue | 375.0 | 407.2 | 1,135.5 | 1,165.0
Net Income (Loss) Attributable to ALLETE | 27.1 | 45.0 | 115.1 | 128.7
Operating Segments |  |  |  |
Business Segments [Line Items] |  |  |  |
Other | 1.5 | 1.3 | 4.4 | 3.8
Total Operating Revenue | 348.4 | 376.4 | 1,054.1 | 1,074.7
Net Income (Loss) Attributable to ALLETE | 30.2 | 49.6 | 113.8 | 145.4
Corporate and Other |  |  |  |
Business Segments [Line Items] |  |  |  |
Other | 0.0 | 0.0 | 0.0 | 0.0
Total Operating Revenue | 26.6 | 30.8 | 81.4 | 90.3
Net Income (Loss) Attributable to ALLETE | (3.1) | (4.6) | 1.3 | (16.7)
Regulated Operations |  |  |  |
Business Segments [Line Items] |  |  |  |
Total Operating Revenue | 320.2 | 310.5 | 958.1 | 928.6
Net Income (Loss) Attributable to ALLETE | 32.5 | 34.0 | 93.9 | 111.9
Regulated Operations | Operating Segments |  |  |  |
Business Segments [Line Items] |  |  |  |
Other | 0.0 | 0.0 | 0.0 | 0.0
Total Operating Revenue | 320.2 | 310.5 | 958.1 | 928.6
Net Income (Loss) Attributable to ALLETE | 32.5 | 34.0 | 93.9 | 111.9
Regulated Operations | Residential |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | 43.5 | 41.9 | 139.9 | 130.5
Regulated Operations | Commercial |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | 50.1 | 49.5 | 147.1 | 143.0
Regulated Operations | Municipal |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | 9.4 | 9.2 | 27.2 | 25.6
Regulated Operations | Industrial |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | 143.0 | 149.8 | 420.1 | 456.1
Regulated Operations | Other Power Suppliers |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | 47.2 | 32.0 | 141.6 | 102.4
Regulated Operations | Other |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | 27.0 | 28.1 | 82.2 | 71.0
ALLETE Clean Energy |  |  |  |
Business Segments [Line Items] |  |  |  |
Total Operating Revenue | 12.3 | 34.1 | 44.1 | 68.9
Net Income (Loss) Attributable to ALLETE | (3.6) | 3.9 | 4.7 | 10.1
ALLETE Clean Energy | Operating Segments |  |  |  |
Business Segments [Line Items] |  |  |  |
Other | 1.5 | 1.3 | 4.4 | 3.8
Total Operating Revenue | 12.3 | 34.1 | 44.1 | 68.9
Net Income (Loss) Attributable to ALLETE | (3.6) | 3.9 | 4.7 | 10.1
ALLETE Clean Energy | Long-term PSA |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | 10.8 | 9.9 | 39.7 | 42.2
ALLETE Clean Energy | Sale of Wind Energy Facilities | Operating Segments |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | 0.0 | 22.9 | 0.0 | 22.9
ALLETE Clean Energy | Other |  |  |  |
Business Segments [Line Items] |  |  |  |
Other | 1.5 | 1.3 | 4.4 | 3.8
New Energy |  |  |  |
Business Segments [Line Items] |  |  |  |
Total Operating Revenue | 15.9 | 31.8 | 51.9 | 77.2
Net Income (Loss) Attributable to ALLETE | 1.3 | 11.7 | 15.2 | 23.4
New Energy | Operating Segments |  |  |  |
Business Segments [Line Items] |  |  |  |
Other | 0.0 | 0.0 | 0.0 | 0.0
Total Operating Revenue | 15.9 | 31.8 | 51.9 | 77.2
Net Income (Loss) Attributable to ALLETE | 1.3 | 11.7 | 15.2 | 23.4
New Energy | Sale of Renewable Development Projects |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | 8.0 | 29.2 | 36.2 | 68.7
New Energy | Other |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | 7.9 | 2.6 | 15.7 | 8.5
Corporate and Other |  |  |  |
Business Segments [Line Items] |  |  |  |
Total Operating Revenue | 26.6 | 30.8 | 81.4 | 90.3
Net Income (Loss) Attributable to ALLETE | (3.1) | (4.6) | 1.3 | (16.7)
Corporate and Other | Long-term Contract |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | 23.8 | 26.7 | 72.3 | 79.4
Corporate and Other | Other |  |  |  |
Business Segments [Line Items] |  |  |  |
Operating Revenue | $ 2.8 | $ 4.1 | $ 9.1 | $ 10.9

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