Retirement Plans and Other Employee Benefits - Schedule of Amounts Recognized in Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Benefits
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net actuarial (gain) loss arising during measurement period	$ 17	$ 32	$ 13
Items amortized during the measurement period:
Net actuarial gain (loss)	(13)	(11)	(10)
Total recognized in other comprehensive income	4	21	3
Other Benefits
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net actuarial (gain) loss arising during measurement period	0	(3)	(7)
Items amortized during the measurement period:
Net actuarial gain (loss)	1	0	0
Total recognized in other comprehensive income	$ 1	$ (3)	$ (7)