Employee Benefit Plans - Schedule of Fair Value of Pension Plan Assets by Asset Category - Additional Information (Details) - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
International markets, United Kingdom [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	14.00%	17.00%
International markets, United Kingdom [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	14.00%	17.00%
International markets, Switzerland [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	8.00%	7.00%
International markets, Switzerland [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	8.00%	7.00%
International markets, Ireland [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	8.00%	6.00%
International markets, Ireland [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	8.00%	6.00%
International markets, Japan [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	7.00%	10.00%
International markets, Japan [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	7.00%	10.00%
International markets, France [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	7.00%	8.00%
International markets, France [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	7.00%	8.00%
International markets, South Korea [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	6.00%
International markets, South Korea [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	6.00%
International markets, Canada [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	6.00%
International markets, Canada [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	6.00%
International markets, emerging markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	18.00%	17.00%
International markets, emerging markets [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	18.00%	17.00%
International markets, no concentration greater than 5% in any one country[Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	26.00%	35.00%
International markets, no concentration greater than 5% in any one country[Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	26.00%	35.00%
Mutual funds [Member] | U.S. Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	40.00%	37.00%
Mutual funds [Member] | US Treasuries and Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	33.00%	38.00%
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	24.00%	30.00%
Corporate debt [Member] | U.S. Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	86.00%	85.00%
Corporate debt [Member] | U.S. Companies [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	86.00%	85.00%
Corporate debt [Member] | International Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	11.00%	12.00%
Corporate debt [Member] | International Companies [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	11.00%	12.00%
Corporate debt [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%	77.00%
Corporate debt [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%	77.00%
Corporate debt [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%	23.00%
Corporate debt [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%	23.00%
Corporate debt [Member] | Emerging Market Companies [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	3.00%	3.00%
Corporate debt [Member] | Emerging Market Companies [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	3.00%	3.00%
Government securities [Member] | Domestic Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	79.00%	32.00%
Government securities [Member] | Domestic Government Securities [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	79.00%	32.00%
Government securities [Member] | Emerging Market Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	13.00%	37.00%
Government securities [Member] | Emerging Market Government Securities [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	13.00%	37.00%
Government securities [Member] | Other International Government Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	8.00%	31.00%
Government securities [Member] | Other International Government Securities [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	8.00%	31.00%
Government securities [Member] | U.S. Buyout Opportunities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		94.00%
Government securities [Member] | European Buyout Opportunities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		6.00%
Private market partnerships [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan master trust future funding commitments	$ 1.4	$ 1.0
Private market partnerships [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan master trust future funding commitments	$ 1.4	$ 1.0
Private market partnerships [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated period of liquidation of underlying assets	1 year	1 year
Private market partnerships [Member] | Minimum [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated period of liquidation of underlying assets	1 year	1 year
Private market partnerships [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated period of liquidation of underlying assets	10 years	10 years
Private market partnerships [Member] | Maximum [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated period of liquidation of underlying assets	10 years	10 years
Private market partnerships [Member] | U.S. Buyout Opportunities [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		94.00%
Private market partnerships [Member] | European Buyout Opportunities [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		6.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Common Or Collective Trust, Securities Of Larger Companies Within US [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	36.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Common Or Collective Trust, Securities Of Larger Companies Within US [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	36.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Common Or Collective Trust, Securities Of Smaller Companies Outside US [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	29.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Common Or Collective Trust, Securities Of Smaller Companies Outside US [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	29.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Common Or Collective Interest Trust, Short-Term Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	16.00%	37.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Common Or Collective Interest Trust, Short-Term Securities [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	16.00%	37.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Emerging Market 103-12 Investment Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	15.00%	45.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Emerging Market 103-12 Investment Trust [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	15.00%	45.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Canadian Segregated Balanced Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	4.00%	12.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Canadian Segregated Balanced Value [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	4.00%	12.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Common/Collective Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		6.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value [Member] | Common/Collective Trust [Member] | American Airlines, Inc. [Member]
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		6.00%