Selected Balance Sheet Information: Materials, Supplies, and Fuel Schedule (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
|---|---|---|
| Selected Balance Sheet Information [Abstract] | ||
| Materials and supplies | $ 122.7 | $ 117.3 |
| Fuel - Electric Utilities | 6.4 | 6.4 |
| Natural gas in storage | 28.8 | 48.7 |
| Total materials, supplies and fuel | $ 157.9 | $ 172.4 |
| X | ||||||||||
- Definition Selected Balance Sheet Information [Abstract] No definition available.
|
| X | ||||||||||
- Definition Carrying amount as of the balance sheet date of natural gas in storage, which is a mixture of gases (liquefied or otherwise), used for fuel and manufacturing purposes, which is ready for sale. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount of fossil fuel included in inventory classified as other. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Gross amount of unprocessed materials to be used in manufacturing or production process and supplies that will be consumed. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|