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