Employee Benefit Plans - Additional Information (Details)	9 Months Ended
	Sep. 30, 2018 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 467,000,000
Supplemental contributions by employer	425,000,000
Minimum contributions by employer	42,000,000
American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	464,000,000
Supplemental contributions by employer	425,000,000
Minimum contributions by employer	$ 39,000,000