Restructuring Costs And Other Charges (Narrative) (Details) - USD ($) $ in Millions	4 Months Ended	5 Months Ended	9 Months Ended
	Apr. 30, 2021	Sep. 30, 2021	Sep. 30, 2020
Successor [Member]
Restructuring costs		$ 19
Successor [Member] | Severance And Employee Costs [Member]
Restructuring costs		6
Successor [Member] | Professional Fees [Member]
Restructuring costs		$ 13
Predecessor [Member]
Restructuring costs			$ 87
Predecessor [Member] | Transformation Initiatives [Member]
Restructuring costs			8
Predecessor [Member] | Consulting And Advisory [Member]
Restructuring costs			72
Predecessor [Member] | Severance And Employee Costs [Member]
Restructuring costs	$ 7		$ 7