Retirement Plans - Schedule of Net Periodic Pension Cost and Other Comprehensive Income (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Interest cost	$ 6	$ 7	$ 6
Expected return on plan assets	(13)	(11)	(11)
Actuarial loss amortization	3	2	2
Total pension income	(4)	(2)	(3)
Current year actuarial loss	10	1	6
Amortization of actuarial loss	(3)	(2)	(2)
Total amount recognized in other comprehensive income	7	(1)	4
Total amount recognized in net periodic benefit cost and other comprehensive income	$ 3	$ (3)	$ 1