Loss Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Basic and diluted EPS:
Net loss	$ (1,250)	$ (2,241)
Basic (in shares)	634,609	425,713
Diluted (in shares)	634,609	425,713
Basic EPS (in dollars per share)	$ (1.97)	$ (5.26)
Diluted EPS (in dollars per share)	$ (1.97)	$ (5.26)
Restricted stock unit awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	3,255	4,934
Warrant | PSP1 Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	4,957	0
Warrant | Treasury Loan Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	1,545	0
Warrant | PSP2 Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	520	0
6.50% convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities	61,728	0