Basis of Presentation and Summary of Significant Accounting Policies - Significant Contract Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Contract balances, liability	$ 12,878	$ 12,864
Loyalty program [Member]
Disaggregation of Revenue [Line Items]
Contract balances, liability	8,539	8,822
Air traffic [Member]
Disaggregation of Revenue [Line Items]
Contract balances, liability	4,339	4,042
American Airlines, Inc. [Member]
Disaggregation of Revenue [Line Items]
Contract balances, liability	12,878	12,864
American Airlines, Inc. [Member] | Loyalty program [Member]
Disaggregation of Revenue [Line Items]
Contract balances, liability	8,539	8,822
American Airlines, Inc. [Member] | Air traffic [Member]
Disaggregation of Revenue [Line Items]
Contract balances, liability	$ 4,339	$ 4,042