Postretirement Benefit Plans - Summary of Actual Pension Plan Asset Allocation (Detail)	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Actual benefit plan asset allocation	100.00%	100.00%
Equity securities
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Actual benefit plan asset allocation	26.00%	32.00%
Debt securities
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Actual benefit plan asset allocation	38.00%	34.00%
Insurance contracts
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Actual benefit plan asset allocation	7.00%	7.00%
Other
Defined Benefit Plan, Plan Assets, Allocation [Line Items]
Actual benefit plan asset allocation	29.00%	27.00%