Fair Value Measurements and Other Investments - Schedule of Carrying Value and Estimated Fair Value of Long-Term Debt, Including Current Maturities (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Carrying Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, including current maturities	$ 25,065	$ 24,344
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	25,848	24,983
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	23,294	22,577
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	$ 24,029	$ 23,181