Pension Plans and Other Postretirement Benefits - Assumed Weighted-Average Rates Used to Determine Net Benefit Expense (Detail)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	5.00%	2.75%	2.50%
Long-term rate of return on plan assets	6.25%	6.25%	6.25%
Rate of increase in future compensation levels	3.33%	3.35%	3.37%
Other Postretirement Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	5.00%	2.75%	2.50%