Financing: Short-term Debt (Additional Information) (Details) $ in Millions |
1 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
|
Jul. 31, 2026
USD ($)
|
Jun. 30, 2026
USD ($)
|
Jun. 30, 2025
USD ($)
|
Apr. 22, 2026
GW
|
|
| Short-Term Debt [Line Items] | ||||
| Proceeds from refundable advances for construction | $ 285.0 | $ 0.0 | ||
| Wyoming Electric | ||||
| Short-Term Debt [Line Items] | ||||
| Potential load capacity of data center | GW | 1.8 | |||
| Proceeds from refundable advances for construction | $ 285.0 | |||
| Wyoming Electric | Subsequent Event | ||||
| Short-Term Debt [Line Items] | ||||
| Proceeds from refundable advances for construction as amended | $ 377.0 | |||