Employee Retirement Benefits - Components of Net Periodic Costs for Qualified and Supplemental Pension Plans (Detail) - Qualified Pension Plans - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Defined Benefit Plan Disclosure
Service cost	$ 2	$ 2
Interest cost	3	2
Expected return on plan assets	(6)	(5)
Amortization of actuarial loss and prior service cost	0	2
Other	0	2
Total non-service (benefit) cost	(3)	1
Net periodic benefit cost	$ (1)	$ 3