Retirement Plans and Other Employee Benefits - Schedule of Benefit Obligation and Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits
Change in benefit obligation
Benefit obligation, beginning of year	$ 893	$ 836
Interest cost	17	24	$ 30
Actuarial (gain)/loss	(26)	70
Actual benefits paid	(39)	(37)
Benefit obligation, end of year	845	893	836
Change in plan assets
Fair value of plan assets, beginning of year	896	826
Actual return on plan assets	(18)	103
Employer contributions	10	4
Actual benefits paid – settlement payments	(3)	(36)
Actual benefits paid – other payments	(2)	(1)
Premium paid for annuity purchase	(34)	0
Fair value of plan assets, end of year	849	896	826
Funded (unfunded) status of the plans	4	3
Amounts recognized in the Balance Sheets
Other assets	37	40
Other liabilities	(33)	(37)
Net asset (liability) at end of year	4	3
Other Benefits
Change in benefit obligation
Benefit obligation, beginning of year	46	42
Interest cost	1	1	1
Actuarial (gain)/loss	(5)	4
Actual benefits paid	(1)	(1)
Benefit obligation, end of year	41	46	42
Change in plan assets
Fair value of plan assets, beginning of year	23	20
Actual return on plan assets	3	3
Employer contributions	1	1
Actual benefits paid – settlement payments	(1)	(1)
Actual benefits paid – other payments	0	0
Premium paid for annuity purchase	0	0
Fair value of plan assets, end of year	26	23	$ 20
Funded (unfunded) status of the plans	(15)	(23)
Amounts recognized in the Balance Sheets
Other assets	23	20
Other liabilities	(38)	(43)
Net asset (liability) at end of year	$ (15)	$ (23)