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Employee Postretirement Benefits - Composition of Periodic Benefit Cost (Details) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023
Retirement Benefits [Abstract] |  |  |  |
Net Periodic Benefit Cost (Income) | $ (1,651) | $ (1,568) | $ (4,952) | $ (4,700)
Net Amount Amortized Due to the Effect of Regulation | 379 | 374 | 1,038 | 864
Net Periodic Benefit Cost (Income) Recognized | $ (1,272) | $ (1,194) | $ (3,914) | $ (3,836)

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