Business Segment Information: Capital Expenditures and Asset Acquisitions (Details) - USD ($) $ in Millions |
6 Months Ended | |
|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Segment Reporting Information [Line Items] | ||
| Capital Expenditures | $ 369.9 | $ 380.8 |
| Corporate, Non-Segment | ||
| Segment Reporting Information [Line Items] | ||
| Capital Expenditures | 4.3 | 4.8 |
| Electric Utilities | Operating Segments | ||
| Segment Reporting Information [Line Items] | ||
| Capital Expenditures | 211.8 | 185.6 |
| Gas Utilities | Operating Segments | ||
| Segment Reporting Information [Line Items] | ||
| Capital Expenditures | $ 153.8 | $ 190.4 |