Consolidated Statements Of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows provided from (used by) operating activities:
Net income (loss)	$ 60	$ (186)
Adjustments to reconcile net income (loss) to net cash provided from (used by) operating activities:
Depreciation and amortization	387	415
Pension settlement costs		103
Stock-based compensation	(1)	1
Amortization of deferred financing costs		8
Other adjustments	1	1
Deferred income taxes	84	(30)
Loss on disposal of Northwest Operations		24
Change in accounts receivable	34	29
Change in accounts payable and other liabilities	48	110
Change in prepaid expenses, income taxes and other assets	52	2
Net cash provided from operating activities	665	477
Cash flows provided from (used by) investing activities:
Capital expenditures	(384)	(286)
Proceeds on sale of assets	2	2
Other	2	2
Net cash used by investing activities	(380)	(282)
Cash flows used by financing activities:
Long-term debt principal payments		(5)
Finance lease obligation payments	(5)	(8)
Other	(2)
Net cash used by financing activities	(7)	(13)
Increase in cash, cash equivalents and restricted cash	278	182
Cash, cash equivalents and restricted cash at January 1,	1,887	809
Cash, cash equivalents and restricted cash at March 31,	2,165	991
Cash paid during the period for:
Interest	40	163
Income tax payments, net		$ 1
Reorganization items, net	$ 56