Fair Value of Financial Assets and Liabilities - Consideration of Credit Risk Concentrations (Details) - Credit Concentration Risk $ in Millions |
Jun. 30, 2026
USD ($)
Counterparty
|
|---|---|
| Derivative [Line Items] | |
| Significant counterparties | 4 |
| Municipal or cooperative electric entities or other utilities | |
| Derivative [Line Items] | |
| Significant counterparties | 4 |
| External credit rating, investment grade | |
| Derivative [Line Items] | |
| Significant counterparties | 1 |
| Credit exposure | $ | $ 5 |
| Credit exposure, percentage | 18.00% |
| Internal investment grade | |
| Derivative [Line Items] | |
| Significant counterparties | 3 |
| Credit exposure | $ | $ 23 |
| Credit exposure, percentage | 75.00% |