Retirement Benefits - Components of Net Periodic Benefit Cost (Parenthetical) (Detail) - Jun. 30, 2015 - Other Postretirement Benefit Plans [Member] - USD ($) $ in Millions	Total	Total
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service costs	$ 1	$ 1
American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service costs		$ 1