Investments - Schedule of Equity Investments (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	$ 184	$ 212
American Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	184	212
Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	553	610
Equity Securities | American Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 553	$ 610
China Southern Airlines
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Ownership interest, fair value method investments	1.50%	1.50%
Carrying value, fair value method investments	$ 132	$ 176
China Southern Airlines | American Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Ownership interest, fair value method investments	1.50%	1.50%
Carrying value, fair value method investments	$ 132	$ 176
Republic Airways Holdings Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Ownership interest, equity method investments	25.00%	25.00%
Carrying value, equity method investments	$ 237	$ 222
Republic Airways Holdings Inc. | American Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Ownership interest, equity method investments	25.00%	25.00%
Carrying value, equity method investments	$ 237	$ 222