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Pension Plans and Other Postretirement Benefit Plans - Additional Information (Details) - USD ($) $ in Millions | 6 Months Ended
--- | ---
Jun. 30, 2025 | Jun. 30, 2024
Defined Benefit Plan Disclosure [Line Items] |  |
Payment for pension benefits | $ 7 | $ 7
Percentage of service related net periodic benefit costs capitalized to utility property | 45.00% |
Percentage of service related net periodic benefit costs recorded to operating expenses | 55.00% |
Percentage of non-service related net periodic benefit costs capitalized to regulatory assets | 45.00% |
Percentage of non-service related net periodic benefit costs recorded to other expense | 55.00% |
Pension Plans, Defined Benefit [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Expected contributions to pension plan | $ 10 |

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