Retirement Plans and Other Employee Benefits - Schedule of Amounts Recognized in Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net actuarial (gain) loss arising during measurement period	$ 13	$ (8)	$ (14)
Items amortized during the measurement period:
Actuarial (gain)/loss	(10)	(13)	(10)
Total recognized in other comprehensive income	3	(21)	(24)
Other Benefits
Defined Benefit Plan, Amounts Recognized in Other Comprehensive Income (Loss) [Abstract]
Net actuarial (gain) loss arising during measurement period	(7)	3	5
Items amortized during the measurement period:
Actuarial (gain)/loss	0	0	0
Total recognized in other comprehensive income	$ (7)	$ 3	$ 5