Investments - Schedule of Equity Investments (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	$ 120	$ 186
Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	515	541
American Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	120	186
American Airlines, Inc. | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 515	$ 541
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	$ 142	$ 115
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	$ 142	$ 115
Republic Holdings
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	$ 253	$ 240
Republic Holdings | 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	$ 253	$ 240