Employee Retirement Benefits - Components of Net Periodic Costs for Qualified and Supplemental Pension Plans (Detail) - Qualified Pension Plans - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan Disclosure
Service cost	$ 2	$ 2	$ 7	$ 7
Interest cost	3	2	8	7
Expected return on plan assets	(6)	(5)	(17)	(16)
Amortization of actuarial loss and prior service cost	0	2	0	5
Other	0	0	0	2
Total non-service benefit	(3)	(1)	(9)	(2)
Net periodic benefit cost	$ (1)	$ 1	$ (2)	$ 5