Earnings (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jun. 30, 2020
Basic EPS:
Net income (loss)	$ 822	$ 127	$ (1,993)
Weighted average common shares outstanding (in shares)	653,612	650,345	644,015
Basic EPS (in dollars per share)	$ 1.26	$ 0.20	$ (3.09)
Diluted EPS:
Net income (loss)	$ 822	$ 127	$ (1,993)
Interest expense on 6.50% convertible senior notes	46	0	0
Net income (loss) for purposes of computing diluted EPS	$ 868	$ 127	$ (1,993)
Share computation for diluted EPS:
Basic weighted average common shares outstanding (in shares)	653,612	650,345	644,015
Dilutive effect of stock awards (in shares)	1,830	1,579	0
Dilutive effect of certain PSP Warrants and Treasury Loan Warrants (in shares)	2,499	3,198	0
Assumed conversion of 6.50% convertible senior notes (in shares)	61,728	0	0
Diluted weighted average common shares outstanding (in shares)	719,669	655,122	644,015
Diluted EPS (in dollars per share)	$ 1.21	$ 0.19	$ (3.09)
Convertible Senior Notes 6.50% Due 2025 | Senior Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Fixed interest rate per annum	6.50%			6.50%
Restricted stock unit awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	4,371	3,987	3,420
6.50% convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	0	61,728	61,728