Pension And Other Retirement Benefits - Components of Net Periodic Benefit Expense Related to Retirement Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 22	$ 19	$ 20
U.S. Plans | Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	17	19	18
Interest cost	21	17	19
Expected return on plan assets	(20)	(15)	(17)
Amortization of net actuarial loss from earlier periods	4	6	9
Net periodic expense	22	27	29
U.S. Plans | Other Retirement Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	3	3	2
Interest cost	1	1	1
Expected return on plan assets	0	0	0
Amortization of net actuarial loss from earlier periods	0	0	0
Net periodic expense	$ 4	$ 4	$ 3