Pension and Other Post-Retirement Benefits - Pension and Post-Retirement Plans (Details) - Pension Benefits - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Components of net periodic pension expense (credit):
Interest cost	$ 1	$ 1
Expected return on plan assets	(4)	(4)
Amortization of net actuarial loss		2
Net periodic (credit) expense	$ (3)	$ (1)