Retirement and Other Benefit Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation for defined benefit pension plans	$ 879	$ 882
Combined pension plan and SERP contributions	34	32
Estimated contribution of pension plans	40
Corporation's matching obligations	$ 22	22	$ 23
Defined contribution plan name	401(a)
Defined benefit plans remeasurement increased	$ 48
Postretirement Health Care Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation for defined benefit pension plans	$ 7	$ 8