Fair Value Measurements (Reconciliation of Assets and Liabilities Measured At Fair Value On A Recurring Basis Using Unobservable Inputs) (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
|
| Derivatives (net) | ||||
| Balance at beginning of period | $ 3 | $ 6 | $ 9 | $ 15 |
| Purchases, sales, issuances and settlements: | ||||
| Purchases | 14 | 29 | 14 | 29 |
| Settlements | 8 | (10) | 2 | (23) |
| Total (losses) gains included on the Condensed Consolidated Balance Sheet | (11) | 10 | (11) | 14 |
| Balance at end of period | 14 | 35 | 14 | 35 |
| Duke Energy Indiana | ||||
| Derivatives (net) | ||||
| Balance at beginning of period | 2 | 5 | 8 | 13 |
| Purchases, sales, issuances and settlements: | ||||
| Purchases | 12 | 27 | 12 | 27 |
| Settlements | 9 | (9) | 3 | (20) |
| Total (losses) gains included on the Condensed Consolidated Balance Sheet | (10) | 10 | (10) | 13 |
| Balance at end of period | $ 13 | $ 33 | $ 13 | $ 33 |