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, 2020	Dec. 31, 2019
International markets, Switzerland
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	11.00%	8.00%
International markets, Switzerland | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	11.00%	8.00%
International markets, Ireland
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	11.00%	8.00%
International markets, Ireland | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	11.00%	8.00%
International markets, United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	10.00%	14.00%
International markets, United Kingdom | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	10.00%	14.00%
International markets, France
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	9.00%	7.00%
International markets, France | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	9.00%	7.00%
International markets, Japan
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	8.00%	7.00%
International markets, Japan | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	8.00%	7.00%
International markets, Germany
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	7.00%
International markets, Germany | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	7.00%
International markets, Netherlands
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	6.00%
International markets, Netherlands | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	6.00%
International markets, South Korea
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		6.00%
International markets, South Korea | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		6.00%
International markets, Canada
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		6.00%
International markets, Canada | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations		6.00%
International markets, emerging markets
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	13.00%	18.00%
International markets, emerging markets | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	13.00%	18.00%
International markets, no concentration greater than 5% in any one country
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	25.00%	26.00%
International markets, no concentration greater than 5% in any one country | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	25.00%	26.00%
Mutual funds | U.S. Companies
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	39.00%	40.00%
Mutual funds | US Treasuries and Corporate Bonds
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	35.00%	33.00%
Mutual funds | International Companies
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	26.00%	27.00%
Mutual funds | International Companies | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	25.00%	24.00%
Corporate obligations | U.S. Companies
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	89.00%	86.00%
Corporate obligations | U.S. Companies | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	89.00%	86.00%
Corporate obligations | International Companies
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	9.00%	11.00%
Corporate obligations | International Companies | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	9.00%	11.00%
Corporate obligations | Corporate Debt with A Standard and Poor's (S&P) Rating Lower than A
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	77.00%	76.00%
Corporate obligations | Corporate Debt with A Standard and Poor's (S&P) Rating Lower than A | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	77.00%	76.00%
Corporate obligations | Corporate Debt with Standard and Poor's (S&P) Rating A or Higher
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	23.00%	24.00%
Corporate obligations | Corporate Debt with Standard and Poor's (S&P) Rating A or Higher | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	23.00%	24.00%
Corporate obligations | Emerging Market Companies
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	2.00%	3.00%
Corporate obligations | Emerging Market Companies | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	2.00%	3.00%
Government securities | Domestic Government Securities
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	89.00%	79.00%
Government securities | Domestic Government Securities | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	89.00%	79.00%
Government securities | Emerging Market Government Securities
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	9.00%	13.00%
Government securities | Emerging Market Government Securities | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	9.00%	13.00%
Government securities | Other International Government Securities
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	2.00%	8.00%
Government securities | Other International Government Securities | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	2.00%	8.00%
Private Market Partnerships
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan master trust future funding commitments	$ 1.6	$ 1.4
Private Market Partnerships | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan master trust future funding commitments	$ 1.6	$ 1.4
Private Market Partnerships | Minimum
Defined Benefit Plan Disclosure [Line Items]
Estimated period of liquidation of underlying assets	1 year	1 year
Private Market Partnerships | Minimum | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Estimated period of liquidation of underlying assets	1 year	1 year
Private Market Partnerships | Maximum
Defined Benefit Plan Disclosure [Line Items]
Estimated period of liquidation of underlying assets	10 years	10 years
Private Market Partnerships | Maximum | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Estimated period of liquidation of underlying assets	10 years	10 years
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Common or Collective Trust, Securities of Larger Companies within US
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	34.00%	36.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Common or Collective Trust, Securities of Larger Companies within US | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	34.00%	36.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Common or Collective Trust, Emerging Country
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	30.00%	15.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Common or Collective Trust, Emerging Country | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	30.00%	15.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Common or Collective Trust, Securities of Companies outside US
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	21.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Common or Collective Trust, Securities of Companies outside US | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	21.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Common or Collective Interest Trust, Short-term Securities
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	9.00%	16.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Common or Collective Interest Trust, Short-term Securities | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	9.00%	16.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Common or Collective Trust, Securities of Smaller Companies outside US
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 | Common or Collective Trust, Securities of Smaller Companies outside US | American Airlines, Inc.
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 | Common or Collective Trust, Securities of Smaller Companies within US
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	5.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Common or Collective Trust, Securities of Smaller Companies within US | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	5.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Canadian Segregated Balanced Value
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	1.00%	4.00%
Common/collective trusts and 103-12 Investment Trust measured at net asset value | Canadian Segregated Balanced Value | American Airlines, Inc.
Defined Benefit Plan Disclosure [Line Items]
Actual plan asset allocations	1.00%	4.00%