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Employee Benefit Plans - Assumptions Used to Determine Projected and Accumulated Benefit Obligations of Domestic Defined Benefit Pension and Postretirement Benefit Plans (Detail)
Dec. 31, 2019
Dec. 31, 2018
Pre-65    
Defined Benefit Plan Disclosure [Line Items]    
Health care cost trend rate 7.00% 7.00%
Ultimate cost trend rate 4.50% 4.50%
Post-65    
Defined Benefit Plan Disclosure [Line Items]    
Health care cost trend rate 6.80% 6.80%
Ultimate cost trend rate 4.50% 4.50%
Defined benefit pension plans    
Defined Benefit Plan Disclosure [Line Items]    
Discount rate 3.00% 4.10%
Postretirement benefit plans    
Defined Benefit Plan Disclosure [Line Items]    
Discount rate 3.00% 4.10%
Annual increase in Medicare Part B premium 6.00% 6.00%