Employee Benefit Plans - Summary of Changes in Fair Value of Pension Plan Level 3 Assets (Detail) - Insurance contracts - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at January 1	$ 8	$ 12
Purchases, sales and settlements, net	0	(4)
Fair value of plan assets at December 31	$ 8	$ 8