Leases - Components of Lease Expense (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 1,907
Finance lease cost:
Amortization of assets	78
Interest on lease liabilities	48
Variable lease cost	2,353
Total net lease cost	4,386
American Airlines, Inc. [Member]
Lessee, Lease, Description [Line Items]
Operating lease cost	1,889
Finance lease cost:
Amortization of assets	78
Interest on lease liabilities	48
Variable lease cost	2,353
Total net lease cost	$ 4,368