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Stock-based Compensation Plans - Summary of Assumptions Used to Determine Benefit Obligation (Detail) - Other Post Retirement Benefits
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Weighted average assumptions used to determine benefit obligation:    
Discount rate 2.50% 1.90%
Assumed weighted average healthcare cost trend rates:    
Initial healthcare trend rate 7.00% 6.50%
Ultimate trend rate 4.00% 4.50%
Year ultimate trend rate reached 2033 2024