Consolidated Statements Of Cash Flows - USD ($) $ in Millions	4 Months Ended	5 Months Ended	9 Months Ended
	Apr. 30, 2021	Sep. 30, 2021	Sep. 30, 2020
Successor [Member]
Cash flows provided from (used by) operating activities:
Net income (loss)		$ 225
Adjustments to reconcile net income (loss) to net cash provided from (used by) operating activities:
Depreciation and amortization		452
Stock-based compensation expense		8
Other adjustments		(11)
Deferred income taxes		68
Change in accounts receivable		65
Change in accounts payable and other liabilities		149
Change in prepaid expenses, income taxes and other assets		27
Net cash provided from (used by) operating activities		983
Cash flows provided from (used by) investing activities:
Capital expenditures		(646)
Other		1
Net cash provided from (used by) investing activities		(645)
Cash flows provided from (used by) financing activities:
Long-term debt principal payments		(8)
Finance lease obligation payments		(9)
Net cash provided from (used by) financing activities		(17)
Increase (Decrease) in cash, cash equivalents, and restricted cash		321
Cash, cash equivalents, and restricted cash at the beginning of the period		940
Cash, cash equivalents, and restricted cash at the end of the period	$ 940	1,261
Cash paid during the period for:
Interest		121
Income tax payments, net		27
Predecessor [Member]
Cash flows provided from (used by) operating activities:
Net income (loss)	4,541		$ (352)
Adjustments to reconcile net income (loss) to net cash provided from (used by) operating activities:
Depreciation and amortization	506		1,204
Pension settlement costs			159
Stock-based compensation expense	(1)		3
Amortization of deferred financing costs			13
Non-cash reorganization items, net	(5,467)		85
Other adjustments	1		3
Deferred income taxes	(148)		(100)
Loss on disposal of Northwest Operations			160
Change in accounts receivable	36		63
Change in accounts payable and other liabilities	(168)		334
Change in prepaid expenses, income taxes and other assets	46		(80)
Net cash provided from (used by) operating activities	(654)		1,492
Cash flows provided from (used by) investing activities:
Capital expenditures	(500)		(825)
Proceeds from sale of Northwest Operations			1,131
Proceeds on sale of assets	9		7
Other	1		2
Net cash provided from (used by) investing activities	(490)		315
Cash flows provided from (used by) financing activities:
Long-term debt principal payments	(1)		(5)
Proceeds from long-term debt borrowings	225
Repayment of revolving debt			(749)
Financing costs paid	(4)		(19)
Finance lease obligation payments	(7)		(18)
Other	(16)
Net cash provided from (used by) financing activities	197		(791)
Increase (Decrease) in cash, cash equivalents, and restricted cash	(947)		1,016
Cash, cash equivalents, and restricted cash at the beginning of the period	1,887	$ 940	809
Cash, cash equivalents, and restricted cash at the end of the period	940		1,825
Cash paid during the period for:
Interest	84		548
Income tax payments, net	9		6
Reorganization items, net	$ 1,397		$ 134