Retirement Benefits - Weighted Average Actuarial Assumptions to Determine Benefit Obligations (Detail)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	1.50%	2.20%
Rate of compensation increase		3.30%
Domestic Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.40%	4.50%
Expected return on plan assets	8.50%	8.50%	8.50%
Rate of compensation increase	2.50%	2.60%
Assumed for next year	6.30%	6.40%
Ultimate rate	4.30%	4.30%
Year that the ultimate rate is reached	2035	2035