Pension Plans and Other Postretirement Benefits - Assumed Weighted-Average Rates Used to Determine Net Benefit Expense (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	2.50%	3.25%	4.25%
Long-term rate of return on plan assets	6.25%	6.50%	6.50%
Rate of increase in future compensation levels	3.37%	4.29%	4.31%
Other Postretirement Benefits [Member]
Pension Plans, Postretirement and Other Employee Benefits [Line Items]
Discount rate	2.50%	3.25%	4.25%