Pension Plan and Other Postretirement Benefits (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	$ 1	$ 1
Benefit obligation	13		$ 13
Pension
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost	1	$ 0
Benefit obligation	$ 12		$ 12
Non-Qualified Supplemental Employee Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Treasury stock acquired (in shares)	1,745		2,035