Employee Benefit Plans - Schedule of Fair Value of Pension Plan Assets by Asset Category (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
International Markets [Member] | United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	17.00%	15.00%
International Markets [Member] | Japan [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	11.00%	12.00%
International Markets [Member] | France [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	9.00%	10.00%
International Markets [Member] | Switzerland [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	6.00%	7.00%
International Markets [Member] | Netherlands [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		6.00%
International Markets [Member] | Emerging Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	16.00%	17.00%
International Markets [Member] | No Concentration Greater than 5% In Any One Country [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	41.00%	33.00%
International Markets [Member] | American Airlines, Inc. [Member] | United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	17.00%	15.00%
International Markets [Member] | American Airlines, Inc. [Member] | Japan [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	11.00%	12.00%
International Markets [Member] | American Airlines, Inc. [Member] | France [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	9.00%	10.00%
International Markets [Member] | American Airlines, Inc. [Member] | Switzerland [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	6.00%	7.00%
International Markets [Member] | American Airlines, Inc. [Member] | Netherlands [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		6.00%
International Markets [Member] | American Airlines, Inc. [Member] | Emerging Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	16.00%	17.00%
International Markets [Member] | American Airlines, Inc. [Member] | No Concentration Greater than 5% In Any One Country [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	41.00%	33.00%
Mutual Funds [Member] | U.S. Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	39.00%	42.00%
Mutual Funds [Member] | US Treasuries and Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	34.00%	33.00%
Mutual Funds [Member] | International Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	27.00%	25.00%
Mutual Funds [Member] | International Companies [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	30.00%	27.00%
Corporate Bonds [Member] | U.S. Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	85.00%	86.00%
Corporate Bonds [Member] | U.S. Companies [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	85.00%	86.00%
Corporate Bonds [Member] | International Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	12.00%	12.00%
Corporate Bonds [Member] | International Companies [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	12.00%	12.00%
Corporate Bonds [Member] | Corporate Debt with A Standard and Poor's (S&P) Rating Lower than A [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	76.00%	74.00%
Corporate Bonds [Member] | Corporate Debt with A Standard and Poor's (S&P) Rating Lower than A [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	76.00%	74.00%
Corporate Bonds [Member] | Corporate Debt with Standard and Poor's (S&P) Rating A or Higher [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	24.00%	26.00%
Corporate Bonds [Member] | Corporate Debt with Standard and Poor's (S&P) Rating A or Higher [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	24.00%	26.00%
Corporate Bonds [Member] | Emerging Market Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	3.00%	2.00%
Corporate Bonds [Member] | Emerging Market Companies [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	3.00%	2.00%
Government Securities [Member] | Domestic Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	27.00%	61.00%
Government Securities [Member] | Domestic Government Securities [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	27.00%	61.00%
Government Securities [Member] | Emerging Market Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	43.00%	39.00%
Government Securities [Member] | Emerging Market Government Securities [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	43.00%	39.00%
Government Securities [Member] | Other International Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	30.00%
Government Securities [Member] | Other International Government Securities [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	30.00%
Government Securities [Member] | U.S. Buyout Opportunities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		95.00%
Government Securities [Member] | European Buyout Opportunities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		5.00%
Private Equity Partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan master trust future funding commitments	$ 903	$ 456
Private Equity Partnerships [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan master trust future funding commitments	$ 903	$ 456
Private Equity Partnerships [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated year of liquidation of underlying assets	1 year	1 year
Private Equity Partnerships [Member] | Minimum [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated year of liquidation of underlying assets	1 year	1 year
Private Equity Partnerships [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated year of liquidation of underlying assets	10 years	10 years
Private Equity Partnerships [Member] | Maximum [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated year of liquidation of underlying assets	10 years	10 years
Private Equity Partnerships [Member] | U.S. Buyout Opportunities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	94.00%
Private Equity Partnerships [Member] | U.S. Buyout Opportunities [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	94.00%	95.00%
Private Equity Partnerships [Member] | European Buyout Opportunities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	6.00%
Private Equity Partnerships [Member] | European Buyout Opportunities [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	6.00%	5.00%
Common/Collective Trust and 103-2 Investment Trusts [Member] | Collective Interest Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	42.00%
Common/Collective Trust and 103-2 Investment Trusts [Member] | Collective Interest Trust [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	42.00%
Common/Collective Trust and 103-2 Investment Trusts [Member] | Emerging Market 103-12 Investment Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	40.00%	73.00%
Common/Collective Trust and 103-2 Investment Trusts [Member] | Emerging Market 103-12 Investment Trust [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	40.00%	73.00%
Common/Collective Trust and 103-2 Investment Trusts [Member] | Canadian Segregated Balanced Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	10.00%	12.00%
Common/Collective Trust and 103-2 Investment Trusts [Member] | Canadian Segregated Balanced Value [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	10.00%	12.00%
Common/Collective Trust and 103-2 Investment Trusts [Member] | Common/Collective Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	8.00%	15.00%
Common/Collective Trust and 103-2 Investment Trusts [Member] | Common/Collective Trust [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	8.00%	15.00%