Risk Management Activities (Schedule of Gains (Losses) on Commodity Price Risk Programs) (Details) - USD ($) $ in Millions |
Sep. 30, 2024 |
Dec. 31, 2023 |
|---|---|---|
| Deferred Derivative Gain (Loss) | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Regulatory Liabilities | $ 19.2 | $ 23.3 |
| Deferred Derivative Gain (Loss) | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Regulatory Assets | $ 11.8 | $ 24.4 |