Employee Benefits - Components of Net Periodic Benefit Cost and Changes in Plan Assets and Benefit Obligations Recognized in OCI (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Other Cost (Credit)	$ 17
Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost for benefits earned(1)	1	$ 1	$ 1
Interest cost on projected benefit obligation(2)	1	2	2
Net amortization of deferrals(2)	(20)	(5)	(5)
Net periodic benefit cost	(12)	(2)	$ (2)
Net actuarial loss (gain)	(3)	5
Recognized actuarial loss	(2)	(1)
Recognized prior service credit	6	6
Total (gain) loss recognized in OCI (before tax effects)	1	$ 10
Postretirement Benefit Plan [Member] | Restatement Adjustment [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost on projected benefit obligation(2)	$ 7