Earnings (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Basic EPS:
Net income (loss)	$ (1,993)	$ (8,885)	$ 1,686
Weighted average common shares outstanding (in shares)	644,015	483,888	443,363
Basic EPS (in dollars per share)	$ (3.09)	$ (18.36)	$ 3.80
Diluted EPS:
Net income (loss) for purposes of computing diluted EPS	$ (1,993)	$ (8,885)	$ 1,686
Share computation for diluted EPS:
Basic weighted average common shares outstanding (in shares)	644,015	483,888	443,363
Dilutive effect of stock awards (in shares)	0	0	906
Diluted weighted average common shares outstanding (in shares)	644,015	483,888	444,269
Diluted EPS (in dollars per share)	$ (3.09)	$ (18.36)	$ 3.79
6.50% convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	61,728	31,882	0
Warrant | PSP1 Warrant
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	5,392	349	0
Warrant | PSP2 Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	1,300	0	0
Restricted stock unit awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	3,420	4,584	2,520
Treasury Loan Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	1,681	107	0