Employee Retirement Benefits - Components of Net Periodic Costs for Qualified and Supplemental Pension Plans (Details) - Qualified Pension Plans - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Defined Benefit Plan Disclosure
Service cost	$ 1	$ 2
Interest cost	3	3
Expected return on plan assets	(5)	(6)
Amortization of actuarial loss and prior service cost	(1)	0
Other	(5)	0
Total non-service benefit	(8)	(3)
Net periodic benefit cost	$ (7)	$ (1)