Restructuring And Other Charges (Narrative) (Details) - USD ($) $ in Millions	4 Months Ended	8 Months Ended	12 Months Ended
	Apr. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Successor [Member]
Restructuring costs and other charges		$ 21
Successor [Member] | Severance And Employee Costs [Member]
Restructuring costs and other charges		11
Successor [Member] | Professional Fees [Member]
Restructuring costs and other charges		$ 10
Predecessor [Member]
Restructuring costs and other charges	$ 7		$ 87	$ 168
Predecessor [Member] | Transformation Initiatives [Member]
Restructuring costs and other charges			8	46
Predecessor [Member] | Pension/OPEB Special Termination Benefit Enhancements [Member]
Restructuring costs and other charges				44
Predecessor [Member] | Severance And Employee Costs [Member]
Restructuring costs and other charges	$ 7		7	38
Predecessor [Member] | Consulting And Advisory [Member]
Restructuring costs and other charges			$ 72	$ 40