Debt - Summary of Availability under Revolving Credit Facilities (Detail) - Secured Debt [Member] - Revolving Credit Facility [Member] - USD ($)	Dec. 31, 2017	Aug. 31, 2017	Jun. 30, 2017	Mar. 31, 2017
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 2,500,000,000
Credit Facility 2013 [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	1,200,000,000	$ 1,200,000,000.0		$ 1,400,000,000.0
Credit Facility 2014 [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	1,000,000,000	1,000,000,000.0	$ 1,025,000,000.000
April 2016 Credit Facilities [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	300,000,000	300,000,000
American Airlines, Inc. [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	2,500,000,000
American Airlines, Inc. [Member] | Credit Facility 2013 [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	1,200,000,000	1,200,000,000.0		$ 1,400,000,000.0
American Airlines, Inc. [Member] | Credit Facility 2014 [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	1,000,000,000	1,000,000,000.0	$ 1,025,000,000.000
American Airlines, Inc. [Member] | April 2016 Credit Facilities [Member]
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 300,000,000	$ 300,000,000