Earnings (Loss) Per Share - Summary of Warrants Outstanding (Details) $ / shares in Units, shares in Millions	9 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares
Class of Warrant or Right [Line Items]
Number of shares of common stock (in shares)	10.0
PSP1 Note | Unsecured Debt
Class of Warrant or Right [Line Items]
Face amount | $	$ 1,500,000,000
Term of debt	10 years
PSP1 Warrants
Class of Warrant or Right [Line Items]
Number of shares of common stock (in shares)	4.8
Exercise price (in dollars per share) | $ / shares	$ 31.50
CARES Act Loan Warrants
Class of Warrant or Right [Line Items]
Number of shares of common stock (in shares)	1.7
Exercise price (in dollars per share) | $ / shares	$ 31.50
PSP2 Warrants
Class of Warrant or Right [Line Items]
Number of shares of common stock (in shares)	2.0
Exercise price (in dollars per share) | $ / shares	$ 43.26
PSP3 Warrants
Class of Warrant or Right [Line Items]
Number of shares of common stock (in shares)	1.5
Exercise price (in dollars per share) | $ / shares	$ 53.92