Benefit Plans - Schedule of Changes in and Amount of Accumulated Postretirement Benefit Obligation (Details) - Postretirement Benefit Plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Balance as of beginning of period	$ 54	$ 51
Service cost	1	1
Interest cost	1	2
Benefits paid	(3)	(4)
Actuarial (gains) losses	(5)	4
Balance as of end of period	$ 48	$ 54