Leases (Components Of Lease Cost) (Details) - USD ($) $ in Millions	4 Months Ended	8 Months Ended	12 Months Ended
	Apr. 30, 2021	Dec. 31, 2021	Dec. 31, 2020
Successor [Member]
Lessee, Lease, Description [Line Items]
Amortization of right-of-use assets		$ 13
Interest on lease liabilities		6
Finance lease cost		19
Operating lease cost		38
Short-term lease cost		2
Variable lease cost		4
Sublease income		(11)
Total Lease cost		$ 46
Predecessor [Member]
Lessee, Lease, Description [Line Items]
Amortization of right-of-use assets	$ 7		$ 15
Interest on lease liabilities	4		13
Finance lease cost	11		28
Operating lease cost	19		68
Short-term lease cost	1		2
Variable lease cost	2		6
Sublease income	(4)		(11)
Total Lease cost	$ 26		$ 85