Summary Of Net Periodic Benefit Cost (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 5	$ 5	$ 6
Interest cost	17	21	19
Expected return on plan assets	(31)	(30)	(33)
Defined Benefit Plan Amortization Of Unrecognized Amounts	9	7	7
Net periodic benefit cost	0	3	(1)
Employee Benefit Plans [Abstract]
Defined Benefit Plan, Benefit Obligation	926	821	722
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	(84)	(87)
Defined Benefit Plan, Benefit Obligation, Foreign Currency Translation Gain (Loss)	26	13
Defined Benefit Plan, Plan Assets, Amount	722	649	$ 549
Actual return on plan assets	71	91
Employer contributions	14	21
Defined Benefit Plan, Plan Assets, Foreign Currency Translation Gain (Loss)	14	14
Operating Expense [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	4
Selling, General and Administrative Expenses [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1	$ 1