Retirement Plans and Other Postretirement Benefits - Summary of Corporation's Pension Plan Asset Allocation (Detail)	Dec. 31, 2023	Dec. 31, 2022
Summary of corporation's pension plan asset allocation
Assets category, total	100.00%	100.00%
Equity Securities [Member]
Summary of corporation's pension plan asset allocation
Assets category, total	64.00%	62.00%
Debt Securities [Member]
Summary of corporation's pension plan asset allocation
Assets category, total	34.00%	36.00%
Other [Member]
Summary of corporation's pension plan asset allocation
Assets category, total	2.00%	2.00%