Earnings (Loss) Per Share - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Earnings (loss) available to common stockholders	$ 1,137	$ 942	$ 2,018	$ (106)
Basic weighted-average shares outstanding(in shares)	328.0	326.8	327.8	326.2
Dilutive effect of stock warrants (in shares)	2.7	1.0	2.5	0.0
Dilutive effect of employee stock awards (in shares)	1.7	1.7	1.5	0.0
Diluted weighted-average shares outstanding (in shares)	332.4	329.5	331.8	326.2
Earnings (loss) per share, basic (in dollars per share)	$ 3.47	$ 2.88	$ 6.16	$ (0.33)
Earnings (loss) per share, diluted (in dollars per share)	$ 3.42	$ 2.86	$ 6.08	$ (0.33)
CARES Act Loan Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Warrants to purchase securities (in shares)	10.0		10.0
CARES Act Loan Warrants | Minimum
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Warrant exercise price (in dollars per share)	$ 31.50		$ 31.50
CARES Act Loan Warrants | Maximum
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Warrant exercise price (in dollars per share)	$ 53.92		$ 53.92
Stock warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	1.5	3.5	1.5	3.5
Employee stock awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities (in shares)	0.6	0.7	0.6	0.7