Employee Benefits - Weighted Average Assumptions used to Determine Benefit Obligations and Net Periodic Benefit Cost - Postretirement Benefits Other Than Pensions (Detail) - Post-Retirement Benefits Other Than Pensions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Weighted average assumptions used to determine benefit obligations:
Discount rate	2.86%	2.55%
Weighted average assumptions used to determine net periodic benefit cost:
Discount rate	2.55%	3.34%