Special Items - Additional Disclosures (Detail) - $ / Employees	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Tax reform bonus, amount per employee	1,000
Mainline [Member]
Restructuring Cost and Reserve [Line Items]
Tax reform bonus, amount per employee		1,000
American Airlines, Inc. [Member]
Restructuring Cost and Reserve [Line Items]
Tax reform bonus, amount per employee	1,000
American Airlines, Inc. [Member] | Mainline [Member]
Restructuring Cost and Reserve [Line Items]
Tax reform bonus, amount per employee		1,000