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v3.23.2

Business Segments (Details) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2023 USD ($) | Jun. 30, 2022 USD ($) | Jun. 30, 2023 USD ($) Segments | Jun. 30, 2022 USD ($) | Dec. 31, 2022 USD ($)
Business Segments [Line Items] |  |  |  |  |
Number of Reportable Segments | Segments |  |  | 2 |  |
Operating Revenue | $ 533.4 | $ 373.1 | $ 1,098.3 | $ 756.6 |
Net Income Attributable to ALLETE | 51.5 | 37.6 | 109.7 | 103.9 |
Assets | 6,567.9 |  | $ 6,567.9 |  | $ 6,845.6
Regulated Operations [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Number of Operating Segments | Segments |  |  | 3 |  |
Operating Revenue | 292.2 | 308.7 | $ 604.8 | 637.7 |
Net Income Attributable to ALLETE | 37.8 | 29.6 | 78.4 | 81.1 |
Assets | 4,259.8 |  | 4,259.8 |  | 4,291.4
Regulated Operations [Member] | Residential [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 36.0 | 40.6 | 85.4 | 96.6 |
Regulated Operations [Member] | Commercial [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 44.0 | 44.4 | 91.7 | 92.7 |
Regulated Operations [Member] | Municipal [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 7.6 | 10.0 | 16.5 | 22.1 |
Regulated Operations [Member] | Industrial [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 140.2 | 150.6 | 285.1 | 298.4 |
Regulated Operations [Member] | Other Power Suppliers [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 36.3 | 36.9 | 72.2 | 77.9 |
Regulated Operations [Member] | Other [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 28.1 | 26.2 | 53.9 | 50.0 |
ALLETE Clean Energy [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 181.1 | 21.2 | 382.6 | 49.4 |
Net Income Attributable to ALLETE | 3.1 | 5.8 | 11.6 | 22.3 |
Assets | 1,557.9 |  | 1,557.9 |  | 1,873.3
ALLETE Clean Energy [Member] | Long-term PSA [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 13.2 | 18.9 | 31.6 | 44.3 |
ALLETE Clean Energy [Member] | Other [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue, Other Than Customer Revenue | 1.3 | 2.3 | 2.6 | 5.1 |
ALLETE Clean Energy [Member] | Sale of Wind Energy Facility |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 166.6 | 0.0 | 348.4 | 0.0 |
Corporate and Other [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 60.1 | 43.2 | 110.9 | 69.5 |
Net Income Attributable to ALLETE | 10.6 | 2.2 | 19.7 | 0.5 |
Assets | 750.2 |  | 750.2 |  | $ 680.9
Corporate and Other [Member] | New Energy |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Business Combination, Acquisition Related Costs |  |  |  | 3.0 |
Purchase Price Accounting Impact |  |  | 4.0 |  |
Corporate and Other [Member] | Long-term Contract [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 23.9 | 21.4 | 49.4 | 44.0 |
Corporate and Other [Member] | Other [Member] |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | 3.6 | 7.3 | 9.1 | 11.0 |
Corporate and Other [Member] | Sale of Renewable Development Projects |  |  |  |  |
Business Segments [Line Items] |  |  |  |  |
Operating Revenue | $ 32.6 | $ 14.5 | $ 52.4 | $ 14.5 |

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