Investments (Details) - USD ($) $ in Millions	Dec. 31, 2025	Nov. 30, 2025	Oct. 31, 2025	Dec. 31, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	$ 146			$ 120
Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	603			515
American Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other investments	146			120
American Airlines, Inc. | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total	$ 603			$ 515
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	$ 203			$ 142
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	$ 203			$ 142
Republic Holdings
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Ownership interest, equity method investments	20.80%	20.80%	25.00%	25.00%
Carrying value, equity method investments	$ 254			$ 253
Republic Holdings | American Airlines, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Ownership interest, equity method investments	20.80%	20.80%	25.00%	25.00%
Carrying value, equity method investments	$ 254			$ 253