Employee Benefit Plans - Summary of Changes in Fair Value of Plan's Level Three Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 568
Fair value of plan assets at end of year	582	$ 568
Fair Value, Inputs, Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	63	55
Actual return on plan assets still held at reporting date		10
Purchases, sales and settlements	(3)	(1)
Currency translation adjustments	6	(1)
Fair value of plan assets at end of year	$ 66	$ 63