Pension and Other Postretirement Benefits - Schedule of Pension, Postretirement and Supplemental Retirement Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Pension Plans
Change in benefit obligation:
Benefit obligation at beginning of year	$ 162	$ 215
Interest cost	8	6	$ 5
Actuarial loss (gain)	6	(45)
Benefits paid	(12)	(9)
(Gain) loss due to settlement	1	(5)
Benefit obligation at end of year	165	162	215
Change in plan assets:
Fair value of plan assets at beginning of year	124	166
Actual return on plan assets	12	(33)
Employer contributions	10	3
Benefits paid	(12)	(9)
(Loss) gain due to settlement	0	(3)
Fair value of plan assets at end of year	134	124	166
Funded status of the plans at year end	(31)	(38)
Postretirement Benefit Plans
Change in benefit obligation:
Benefit obligation at beginning of year	1	2
Interest cost	0	0	0
Actuarial loss (gain)	0	0
Benefits paid	0	(1)
(Gain) loss due to settlement	0	0
Benefit obligation at end of year	1	1	2
Change in plan assets:
Fair value of plan assets at beginning of year	1	1
Actual return on plan assets	0	0
Employer contributions	0	0
Benefits paid	0	0
(Loss) gain due to settlement	0	0
Fair value of plan assets at end of year	1	1	1
Funded status of the plans at year end	0	0
Supplemental Retirement Plans
Change in benefit obligation:
Benefit obligation at beginning of year	17	22
Interest cost	1	1	1
Actuarial loss (gain)	0	(5)
Benefits paid	(1)	(1)
(Gain) loss due to settlement	0	0
Benefit obligation at end of year	17	17	22
Change in plan assets:
Fair value of plan assets at beginning of year	11	12
Actual return on plan assets	1	(1)
Employer contributions	1	1
Benefits paid	(1)	(1)
(Loss) gain due to settlement	0	0
Fair value of plan assets at end of year	12	11	$ 12
Funded status of the plans at year end	$ (5)	$ (6)