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Employee Postretirement Benefits - Composition of Periodic Benefit Cost (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2022 | Sep. 30, 2021
Retirement Benefits [Abstract] |  |  |  |
Net Periodic Benefit Cost | $ 1,476 | $ 2,840 | $ 4,435 | $ 8,524
Net Amount Amortized (Deferred) Due to the Effect of Regulation | 499 | 8 | 823 | 15
Net Periodic Benefit Cost Recognized | $ 1,975 | $ 2,848 | $ 5,258 | $ 8,539

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