Fair Value Measurements - Schedule of Carrying Value and Estimated Fair Value of Long-Term Debt, Including Current Maturities (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, including current maturities	$ 24,767	$ 25,065
Fair Value [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, including current maturities	24,932	25,848
American Airlines, Inc. [Member] | Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, including current maturities	23,492	23,294
American Airlines, Inc. [Member] | Fair Value [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, including current maturities	$ 23,640	$ 24,029