Retirement Plans and Other Employee Benefits - Schedule of Benefit Obligation and Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Benefits
Change in benefit obligation
Benefit obligation, beginning of year	$ 663	$ 845
Interest cost	33	20	$ 17
Actuarial (gain)/loss	20	(163)
Actual benefits paid	(41)	(39)
Benefit obligation, end of year	675	663	845
Change in plan assets
Fair value of plan assets, beginning of year	641	849
Actual return on plan assets	35	(172)
Employer contributions	3	3
Actual benefits paid – settlement payments	(2)	(2)
Actual benefits paid – other payments	(1)	(1)
Premium paid for annuity purchase	(38)	(36)
Fair value of plan assets, end of year	638	641	849
Funded (unfunded) status of the plans	(37)	(22)
Amounts recognized in the Balance Sheets
Other assets	0	4
Other liabilities	(37)	(26)
Net asset (liability) at end of year	(37)	(22)
Other Benefits
Change in benefit obligation
Benefit obligation, beginning of year	32	41
Interest cost	2	1	1
Actuarial (gain)/loss	0	(9)
Actual benefits paid	(3)	(1)
Benefit obligation, end of year	31	32	41
Change in plan assets
Fair value of plan assets, beginning of year	21	26
Actual return on plan assets	2	(4)
Employer contributions	3	1
Actual benefits paid – settlement payments	(3)	(2)
Actual benefits paid – other payments	0	0
Premium paid for annuity purchase	0	0
Fair value of plan assets, end of year	23	21	$ 26
Funded (unfunded) status of the plans	(8)	(11)
Amounts recognized in the Balance Sheets
Other assets	21	19
Other liabilities	(29)	(30)
Net asset (liability) at end of year	$ (8)	$ (11)