| Fiscal period | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2018 | 2017 | 2016 | 2015 |
|---|
| Period End Date | 12/31/2024 | 12/31/2023 | 12/31/2022 | 12/31/2021 | 12/31/2020 | 12/31/2019 | 12/31/2018 | 12/31/2017 | 12/31/2016 | 12/31/2015 |
|---|
| Operating Revenue | -- | -- | -- | -- | -- | -- | -- | -- | 1,339.70 | 1,486.40 |
| Energy Services | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Automotive Services | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Contracts with Customers- Utility | 1,242.70 | 1,238.30 | 1,259.30 | 1,227.90 | 987.30 | 1,042.40 | 1,059.50 | 1,063.80 | -- | -- |
| Contracts with Customers- Non-Regulated/Non-Utility | 282.10 | 636.40 | 303.80 | 179.90 | 170.50 | 186.50 | 415.50 | 355.50 | -- | -- |
| Investments | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Prior Year Rate Refunds | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Other - Non-utility | 5.00 | 5.10 | 7.60 | 11.40 | 11.30 | 11.60 | 23.60 | -- | -- | -- |
| Total Revenue | 1,529.80 | 1,879.80 | 1,570.70 | 1,419.20 | 1,169.10 | 1,240.50 | 1,498.60 | 1,419.30 | 1,339.70 | 1,486.40 |
| Cost of Sales | 129.20 | 473.50 | 182.80 | 68.80 | 66.70 | 80.60 | 218.00 | 147.80 | 144.70 | 302.30 |
| Fuel and Purchased Power | -- | -- | -- | -- | -- | -- | -- | -- | 332.90 | 328.10 |
| Fuel and Purchased Power: Utility | 477.60 | 482.90 | 545.50 | 562.40 | 358.60 | 390.70 | 407.50 | -- | -- | -- |
| Fuel and Purchased Power: Nonregulated/Nonutility | -- | -- | -- | -- | -- | -- | -- | 396.90 | -- | -- |
| Depreciation | -- | -- | -- | -- | -- | -- | 205.60 | 177.50 | 195.80 | 170.00 |
| Depreciation and amortization | 271.50 | 251.80 | 242.20 | 231.70 | 217.80 | 202.00 | -- | -- | -- | -- |
| Interest | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Transmission Services | 64.60 | 88.20 | 76.70 | 75.30 | 67.00 | 69.80 | 69.90 | 71.20 | 65.20 | 54.10 |
| Taxes other than income | (65.40) | (57.20) | (70.40) | (70.50) | (56.10) | (53.30) | (57.90) | (56.90) | (53.80) | (51.40) |
| Expense-Other | -- | -- | -- | -- | -- | 0.00 | 2.00 | 0.70 | -- | -- |
| Operating and maintenance | (361.40) | (345.30) | (318.90) | (259.20) | (252.00) | (264.30) | (340.50) | (339.90) | (334.10) | (333.50) |
| Impairment of real estate | -- | -- | -- | -- | -- | -- | -- | -- | 10.30 | (36.30) |
| Operations: Automotive and Investments | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Operations: Nonregulated/Nonutility | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Operations: Utility | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Kendall County Charge | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Total Operating Expenses | 1,369.70 | 1,698.90 | 1,436.50 | 1,267.90 | 1,018.20 | 1,060.70 | 1,297.40 | 1,189.50 | 1,116.20 | 1,275.70 |
| Operating Income (Loss) | 160.10 | 180.90 | 134.20 | 151.30 | 150.90 | 179.80 | 201.20 | 229.80 | 223.50 | 210.70 |
| Interest expense | 81.70 | 80.80 | 75.20 | 69.10 | 65.60 | 64.90 | 67.90 | 67.80 | 70.30 | 64.90 |
| Equity Earnings in ATC | 25.00 | 21.70 | 18.70 | 20.00 | 22.10 | 21.70 | 17.50 | 22.50 | 18.50 | 16.30 |
| Other Income / (Expenses) | 23.00 | 85.00 | 22.40 | 8.70 | 14.70 | 18.70 | 7.80 | 2.40 | 3.90 | 4.70 |
| DISTRIBUTIONS ON REDEEMABLE PREFERRED SECURITIES OF ALLETE CAPITAL | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Gain on Sale of U.S. Water Services | -- | -- | -- | -- | -- | 23.60 | -- | -- | -- | -- |
| Total Non-Operating Income/Expense | (33.70) | 25.90 | (34.10) | (40.40) | (28.80) | (0.90) | (42.60) | (42.90) | (47.90) | (43.90) |
| Income (loss) before minority interest and income taxes | 126.40 | 206.80 | 100.10 | 110.90 | 122.10 | 178.90 | 158.60 | 186.90 | 175.60 | 166.80 |
| Current- Foreign | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Deferred: Foreign | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Change in valuation allowance | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Income tax expense (benefit) | 4.70 | 27.90 | (31.20) | (26.90) | (39.50) | (6.60) | (15.50) | 14.70 | 19.80 | 25.30 |
| Current : Federal | 8.40 | 9.40 | 1.20 | -- | -- | -- | -- | -- | -- | -- |
| Deferred : Federal | (20.10) | (6.00) | (32.80) | (37.20) | (48.80) | (27.80) | (26.20) | 12.10 | 12.00 | 19.40 |
| Deferred : State | 5.00 | 24.00 | (5.20) | 10.80 | 9.80 | 21.70 | 11.00 | 15.80 | 8.10 | 6.50 |
| Current : State | 12.10 | 0.90 | 6.10 | -- | -- | 0.10 | 0.30 | 0.30 | 0.40 | 0.20 |
| Deferred Tax Credits | -- | -- | -- | -- | -- | -- | -- | (13.00) | -- | -- |
| Investment Tax Credit Amortization | (0.70) | (0.40) | (0.50) | (0.50) | (0.50) | (0.60) | (0.60) | (0.50) | (0.70) | (0.80) |
| Minority interest | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Income (loss) from Continuing Operations | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| INCOME (LOSS) FROM DISCONTINUED OPERATIONS - NET OF TAX | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| CHANGE IN ACCOUNTING PRINCIPLE - NET OF TAX | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Net Income before Preferred Dividend & Noncontrolling Interest | 121.70 | 178.90 | 131.30 | 137.80 | 161.60 | 185.50 | 174.10 | 172.20 | 155.80 | 141.50 |
| Non-Controlling Interest in Subsidiaries | (57.60) | (68.20) | (58.00) | (31.40) | (12.60) | (0.10) | -- | -- | 0.50 | 0.40 |
| Net Income (Loss) Available to Common Shareholders | 179.30 | 247.10 | 189.30 | 169.20 | 174.20 | 185.60 | 174.10 | 172.20 | 155.30 | 141.10 |
| EPS (Basic) : Continuing operations | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| EPS (Basic) : Discontinued operations | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| EPS (Basic): Change in accounting principle | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Net Earnings Per Share (Basic) | 3.11 | 4.31 | 3.38 | 3.23 | 3.36 | 3.59 | 3.39 | 3.39 | 3.15 | 2.92 |
| EPS (Diluted) : Continuing operations | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| EPS (Diluted) : Discontinued operations | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| EPS (Diluted): Change in accounting principle | -- | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Net Earnings Per Share (Diluted) | 3.10 | 4.30 | 3.38 | 3.23 | 3.35 | 3.59 | 3.38 | 3.38 | 3.14 | 2.92 |
| Weighted Average Shares Outstanding (Basic) | 57.70 | 57.30 | 55.90 | 52.40 | 51.90 | 51.60 | 51.30 | 50.80 | 49.30 | 48.30 |
| Weighted Average Shares Outstanding (Diluted) | 57.80 | 57.40 | 56.00 | 52.50 | 51.90 | 51.70 | 51.50 | 51.00 | 49.50 | 48.40 |