Basis of Presentation and Summary of Significant Accounting Policies - Finite-Lived Intangible Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	$ (663)	$ (622)
Total	279	320
American Airlines, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	(663)	(622)
Total	279	320
Domestic airport slots [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 365	365
Useful life of intangible assets	25 years
Domestic airport slots [Member] | American Airlines, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 365	365
Useful life of intangible assets	25 years
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 300	300
Useful life of intangible assets	9 years
Customer relationships [Member] | American Airlines, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 300	300
Useful life of intangible assets	9 years
Marketing agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 105	105
Useful life of intangible assets	30 years
Marketing agreements [Member] | American Airlines, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 105	105
Useful life of intangible assets	30 years
Tradenames [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 35	35
Tradenames [Member] | American Airlines, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	35	35
Airport gate leasehold rights [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 137	137
Useful life of intangible assets	25 years
Airport gate leasehold rights [Member] | American Airlines, Inc. [Member]
Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	$ 137	$ 137
Useful life of intangible assets	25 years