Pension Plans and Other Postretirement Benefits - Fair Values of Company's Pension Plan Assets by Asset Category (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Interest and dividend receivable on plan assets	$ 4	$ 4
High-Yielding Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Investment in mutual funds	27.00%	27.00%
Investment Grade Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Investment in mutual funds	73.00%	73.00%