Business Segment Information: Capital Expenditures and Asset Acquisitions (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2023 |
|
| Segment Reporting Information [Line Items] | |||
| Capital Expenditures | $ 889.8 | $ 797.6 | $ 589.9 |
| Corporate, Non-Segment | |||
| Segment Reporting Information [Line Items] | |||
| Capital Expenditures | 11.3 | 13.0 | 7.3 |
| Electric Utilities | Operating Segments | |||
| Segment Reporting Information [Line Items] | |||
| Capital Expenditures | 481.3 | 381.9 | 210.7 |
| Gas Utilities | Operating Segments | |||
| Segment Reporting Information [Line Items] | |||
| Capital Expenditures | $ 397.2 | $ 402.7 | $ 371.9 |