Consolidated Statements Of Cash Flows - 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]
Cash flows provided from (used by) operating activities:
Net income (loss)		$ 414
Adjustments to reconcile net loss to net cash provided from (used by) operating activities:
Depreciation and amortization		734
Loss on early extinguishment of debt
Pension settlement costs
Pension/OPEB special termination benefit enhancements
Stock-based compensation expense		18
Amortization of deferred financing costs
Non-cash reorganization items
Other adjustments		(18)
Deferred income taxes		81
Goodwill impairment
Loss on disposal of Northwest Operations
Change in accounts receivable		59
Change in accounts payable and other liabilities		115
Change in prepaid expenses, income taxes and other assets		48
Net cash provided from (used by) operating activities		1,451
Cash flows provided from (used by) investing activities:
Capital expenditures - Business operations		(1,205)
Proceeds on sale of interest		7
Other		5
Net cash used by investing activities		(1,193)
Cash flows provided from (used by) financing activities:
Long-term debt principal payments		(17)
Proceeds from long-term debt borrowings		1,000
Proceeds from revolving debt
Repayment of revolving debt
Financing costs paid		(13)
Finance lease obligation payments		(13)
Other		23
Net cash provided from (used by) financing activities		980
Increase (Decrease) in cash, cash equivalents, and restricted cash		1,238
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	2,178
Cash paid during the period for:
Interest		281
Income tax payments, net		28
Reorganization items, net
Non-cash investing activities:
Increase (Decrease) in capital expenditures due to changes in accounts payable		(26)
Predecessor [Member]
Cash flows provided from (used by) operating activities:
Net income (loss)	4,541		$ (402)	$ (5,911)
Adjustments to reconcile net loss to net cash provided from (used by) operating activities:
Depreciation and amortization	506		1,598	1,780
Loss on early extinguishment of debt			72	20
Pension settlement costs			159	57
Pension/OPEB special termination benefit enhancements				44
Stock-based compensation expense	(1)		3	15
Amortization of deferred financing costs			15	30
Non-cash reorganization items	(5,467)		93
Other adjustments	1		6
Deferred income taxes	(148)		(91)	(619)
Goodwill impairment				5,725
Loss on disposal of Northwest Operations			162	446
Change in accounts receivable	36		73	48
Change in accounts payable and other liabilities	(168)		342	(122)
Change in prepaid expenses, income taxes and other assets	46		(41)	(5)
Net cash provided from (used by) operating activities	(654)		1,989	1,508
Cash flows provided from (used by) investing activities:
Capital expenditures - Business operations	(500)		(1,181)	(1,226)
Proceeds on sale of interest	9		27	88
Other	1		4	4
Net cash used by investing activities	(490)		(19)	(1,134)
Cash flows provided from (used by) financing activities:
Long-term debt principal payments	(1)		(4,948)	(2,008)
Proceeds from long-term debt borrowings	225		4,950	1,650
Proceeds from revolving debt				949
Repayment of revolving debt			(749)	(475)
Financing costs paid	(4)		(121)	(44)
Finance lease obligation payments	(7)		(23)	(35)
Other	(16)		(2)	(5)
Net cash provided from (used by) financing activities	197		(893)	32
Increase (Decrease) in cash, cash equivalents, and restricted cash	(947)		1,077	406
Cash, cash equivalents, and restricted cash at the beginning of the period	1,887	$ 940	810	404
Cash, cash equivalents, and restricted cash at the end of the period	940		1,887	810
Cash paid during the period for:
Interest	84		612	1,469
Income tax payments, net	9		8	4
Reorganization items, net	1,397		270
Non-cash investing activities:
Increase (Decrease) in capital expenditures due to changes in accounts payable	$ (5)		$ (117)	$ 13