Employee Benefit Plans - Assumptions Used to Calculate Net Periodic Benefit Cost for Domestic Defined Benefit Pension and Postretirement Benefit Plans (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pre-65
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate	7.00%	7.30%	7.00%
Ultimate cost trend rate	4.50%	4.50%		4.50%
Post-65
Defined Benefit Plan Disclosure [Line Items]
Health care cost trend rate	6.80%	7.30%	7.80%
Ultimate cost trend rate	4.50%	4.50%		4.50%
Defined benefit pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.10%	3.40%	3.90%
Long-term rate of return on plan assets	6.00%	6.00%	6.30%
Postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.10%	3.40%	3.90%
Annual increase in Medicare Part B premium	6.00%	6.00%	6.00%