Taxes (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Effective Income Tax Rate Reconciliation, Percent [Abstract] | ||
| Effective income tax rate | 10.80% | 13.10% |
| MGE [Member] | ||
| Effective Income Tax Rate Reconciliation, Percent [Abstract] | ||
| Effective income tax rate | 9.20% | 11.80% |
| Indemnification Agreement [Member] | Renewable Tax Credits Transferred [Member] | ||
| Effects of The Inflation Reduction Act [Abstract] | ||
| Guarantor Obligations, Liquidation Proceeds, Monetary Amount | $ 0.4 | |