Basis of Presentation and Summary of Significant Accounting Policies - Changes in Loyalty Program Liability (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Movement In Contract With Customer, Liability [Roll Forward]
Beginning balance	$ 12,864
Ending balance	12,878
Loyalty program [Member]
Movement In Contract With Customer, Liability [Roll Forward]
Beginning balance	8,822
Deferral of revenue	3,083
Recognition of revenue	(3,366)
Ending balance	$ 8,539
Inactive period before expiration of mileage credits	18 months
Customer liabilities	$ 3,267	$ 3,121
American Airlines, Inc. [Member]
Movement In Contract With Customer, Liability [Roll Forward]
Beginning balance	12,864
Ending balance	12,878
American Airlines, Inc. [Member] | Loyalty program [Member]
Movement In Contract With Customer, Liability [Roll Forward]
Beginning balance	8,822
Deferral of revenue	3,083
Recognition of revenue	(3,366)
Ending balance	$ 8,539
Inactive period before expiration of mileage credits	18 months
Customer liabilities	$ 3,267	$ 3,121