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Fair Value Measurements (Narrative) (Details) | 12 Months Ended | 36 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Dec. 31, 2023 USD ($) | Dec. 31, 2025 USD ($) payment | Mar. 31, 2024 USD ($) | Sep. 30, 2023 USD ($) | Mar. 31, 2023 USD ($) | Sep. 30, 2022 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Hedging Collateral Deposits |  |  | $ 0 | $ 0 | $ 0 | $ 91,670,000
California Asset Sale | Forecast |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Maximum Annual Contingent Payment |  | $ 10,000,000 |  |  |  |
Amount of Each Incremental Contingency Payment |  | 1,000,000 |  |  |  |
Incremental price, exceeding ICE Brent Average Price (in dollars per barrel) |  | 1 |  |  |  |
California Asset Sale | Minimum |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
ICE Brent Average (in dollars per barrel) | $ 95 |  |  |  |  |
California Asset Sale | Minimum | Forecast |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
ICE Brent Average (in dollars per barrel) |  | $ 95 |  |  |  |
California Asset Sale | Maximum | Forecast |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Number Of Annual Contingent Payments | payment |  | 3 |  |  |  |
ICE Brent Average (in dollars per barrel) |  | $ 105 |  |  |  |
Derivative Financial Instruments |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Level 3 Fair Value |  |  | $ 0 |  | $ 0 |

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