Taxes (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Effective Income Tax Rate Reconciliation, Percent [Abstract] | ||||
| Effective income tax rate | 11.40% | 10.10% | 11.00% | 12.00% |
| MGE [Member] | ||||
| Effective Income Tax Rate Reconciliation, Percent [Abstract] | ||||
| Effective income tax rate | 9.80% | 8.40% | 9.40% | 10.50% |
| Indemnification Agreement [Member] | Renewable Tax Credits Transferred [Member] | ||||
| Effects of The Inflation Reduction Act [Abstract] | ||||
| Guarantor Obligations, Liquidation Proceeds, Monetary Amount | $ 9.5 | |||