Basis of Presentation and Recent Accounting Pronouncement (Details)		1 Months Ended		2 Months Ended	3 Months Ended				5 Months Ended	6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) shares	Apr. 30, 2020 USD ($)	May 31, 2020 USD ($)	Dec. 31, 2020	Sep. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) shares	Mar. 31, 2020 USD ($)	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) $ / shares shares	Sep. 30, 2020 USD ($) employee $ / shares shares	Sep. 30, 2019 USD ($)	Dec. 31, 2020 USD ($)	Oct. 21, 2020 USD ($) shares	Oct. 01, 2020 employee	Sep. 29, 2020 USD ($) shares	Sep. 25, 2020 USD ($) $ / shares	Jul. 30, 2020 shares	May 29, 2020 shares	Apr. 20, 2020 shares	Feb. 29, 2020 USD ($)	Jan. 31, 2020 USD ($)
Unusual or Infrequent Item, or Both [Line Items]
Decrease in revenue compared to prior year period (in percentage)						73.00%	86.00%	20.00%
Decrease in flying compared to prior year period (in percentage)						(59.00%)
Number of positions eliminated | employee											5,100
Number of positions eliminated, percent											30.00%
Number of team members opting for early retirement or long-term paid leave (more than) | employee											20,000
Available liquidity	$ 13,600,000,000					$ 13,600,000,000			$ 13,600,000,000	$ 13,600,000,000	$ 13,600,000,000
Unrestricted cash and short-term investments	8,300,000,000					8,300,000,000			8,300,000,000	8,300,000,000	8,300,000,000
Line of credit facility, remaining borrowing capacity	$ 5,327,000,000					$ 5,327,000,000			$ 5,327,000,000	$ 5,327,000,000	$ 5,327,000,000
Issuance of shares of AAG common stock pursuant to a public stock offering (in shares) | shares							85,215,000				85,200,000
Price per share (in dollars per share) | $ / shares	$ 13.50					$ 13.50			$ 13.50	$ 13.50	$ 13.50
Issuance of AAG common stock pursuant to a public stock offering, net of offering costs							$ 1,113,000,000				$ 1,100,000,000
Proceeds from issuance of long-term debt											11,564,000,000	$ 3,550,000,000
Minimum liquidity	$ 2,000,000,000.0					$ 2,000,000,000.0			$ 2,000,000,000.0	$ 2,000,000,000.0	2,000,000,000.0
Financial assistance, CARES Act						(2,100,000,000)					(4,200,000,000)
Subsequent Event
Unusual or Infrequent Item, or Both [Line Items]
Number of team members furloughed | employee															19,000
United States Government, CARES Act, Payroll Support Program
Unusual or Infrequent Item, or Both [Line Items]
Approved financial assistance under the CARES Act			$ 5,800,000,000
Financial assistance received under the CARES Act	168,000,000								6,000,000,000.0
Financial assistance, CARES Act										4,200,000,000
Forecast
Unusual or Infrequent Item, or Both [Line Items]
Decrease in flying compared to prior year period (in percentage)					50.00%
Decrease in long-haul international capacity (in percentage)					0.75
Estimated reduction in operating and capital expenditures													$ 17,000,000,000.0
Increase in liquidity from deferral of payroll taxes under CARES Act													$ 300,000,000
Payroll Support Program Promissory Note
Unusual or Infrequent Item, or Both [Line Items]
Aggregate principal issued	$ 1,800,000,000					$ 1,800,000,000			$ 1,800,000,000	$ 1,800,000,000	$ 1,800,000,000					$ 1,700,000,000
Warrants, number of warrant shares of common stock | shares	14,100,000					14,100,000			14,100,000	14,100,000	14,100,000					13,700,000
Warrants, fair value	$ 63,000,000					$ 63,000,000			$ 63,000,000	$ 63,000,000	$ 63,000,000
Exercise price of warrants (in dollars per share) | $ / shares	$ 12.51					$ 12.51			$ 12.51	$ 12.51	$ 12.51
Treasury Loan Warrants
Unusual or Infrequent Item, or Both [Line Items]
Warrant, number of shares of common stock (in shares) | shares	4,400,000					4,400,000			4,400,000	4,400,000	4,400,000
Exercise price of warrants (in dollars per share) | $ / shares																	$ 12.51
Additional warrants, percentage of borrowing	0.10					0.10			0.10	0.10	0.10
Treasury Loan Warrants | Subsequent Event
Unusual or Infrequent Item, or Both [Line Items]
Warrants, number of warrant shares of common stock | shares														60,000,000.0
Secured Debt | 11.75% Senior Notes
Unusual or Infrequent Item, or Both [Line Items]
Fixed interest rate per annum	11.75%					11.75%			11.75%	11.75%	11.75%
Senior Notes | 3.75% Senior Notes
Unusual or Infrequent Item, or Both [Line Items]
Aggregate principal issued																					$ 500,000,000
Fixed interest rate per annum																					3.75%
Senior Notes | 4.625% Senior Notes
Unusual or Infrequent Item, or Both [Line Items]
Fixed interest rate per annum								4.625%
Repayments of senior notes											$ 500,000,000
Senior Notes | 6.50% Senior Notes
Unusual or Infrequent Item, or Both [Line Items]
Aggregate principal issued	$ 1,000,000,000	$ 1,000,000,000.0				$ 1,000,000,000	$ 1,000,000,000.0		$ 1,000,000,000	$ 1,000,000,000	1,000,000,000
Fixed interest rate per annum		6.50%					6.50%
Proceeds from issuance of long-term debt		$ 970,000,000
Revolving Credit Facility
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, remaining borrowing capacity	400,000,000					400,000,000			400,000,000	400,000,000	400,000,000
Line of Credit
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, remaining borrowing capacity	4,927,000,000					4,927,000,000			4,927,000,000	4,927,000,000	4,927,000,000
Line of Credit | Treasury Loan Agreement, CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, remaining borrowing capacity	4,900,000,000					4,900,000,000			4,900,000,000	4,900,000,000	4,900,000,000
Line of credit facility, maximum borrowing capacity	5,500,000,000					5,500,000,000			5,500,000,000	5,500,000,000	5,500,000,000						$ 5,500,000,000
Borrowings from credit facilities											550,000,000
Line of Credit | Treasury Loan Restatement Agreement, CARES Act | Subsequent Event
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, maximum borrowing capacity														$ 7,500,000,000
American Airlines, Inc.
Unusual or Infrequent Item, or Both [Line Items]
Available liquidity	13,600,000,000					13,600,000,000			13,600,000,000	13,600,000,000	13,600,000,000
Unrestricted cash and short-term investments	8,300,000,000					8,300,000,000			8,300,000,000	8,300,000,000	8,300,000,000
Line of credit facility, remaining borrowing capacity	$ 5,327,000,000					$ 5,327,000,000			$ 5,327,000,000	$ 5,327,000,000	$ 5,327,000,000
Issuance of shares of AAG common stock pursuant to a public stock offering (in shares) | shares											85,200,000
Proceeds from issuance of long-term debt											$ 8,743,000,000	$ 2,800,000,000
American Airlines, Inc. | Secured Debt | 11.75% Senior Notes
Unusual or Infrequent Item, or Both [Line Items]
Fixed interest rate per annum	11.75%					11.75%			11.75%	11.75%	11.75%
American Airlines, Inc. | Secured Debt | Delayed Draw Term Loan Facility
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, maximum borrowing capacity								$ 1,000,000,000.0
American Airlines, Inc. | Secured Debt | Special Facility Revenue Bonds
Unusual or Infrequent Item, or Both [Line Items]
Repayments of long-term debt		47,000,000
Proceeds from issuance of long-term debt		353,000,000
American Airlines, Inc. | Secured Debt | Equipment Loans and Other Notes Payable Maturing 2029 Through 2032
Unusual or Infrequent Item, or Both [Line Items]
Proceeds from sale-leaseback transactions											$ 392,000,000
Proceeds from issuance of long-term debt											197,000,000
American Airlines, Inc. | Secured Debt | Enhanced Equipment Trust Certificates and Other Equipment Financing
Unusual or Infrequent Item, or Both [Line Items]
Proceeds from issuance of long-term debt											323,000,000
American Airlines, Inc. | Secured Debt | Equipment Loans and Other Notes Payable
Unusual or Infrequent Item, or Both [Line Items]
Repayments of long-term debt											17,000,000
American Airlines, Inc. | Senior Notes | 11.75% Senior Notes
Unusual or Infrequent Item, or Both [Line Items]
Aggregate principal issued		$ 2,500,000,000					$ 2,500,000,000
Fixed interest rate per annum		11.75%					11.75%
American Airlines, Inc. | Senior Notes | Special Facility Revenue Bonds
Unusual or Infrequent Item, or Both [Line Items]
Aggregate principal issued		$ 360,000,000					$ 360,000,000
American Airlines, Inc. | Senior Notes | 10.75% Senior Secured Notes
Unusual or Infrequent Item, or Both [Line Items]
Aggregate principal issued	$ 1,200,000,000					$ 1,200,000,000			$ 1,200,000,000	$ 1,200,000,000	1,200,000,000
Fixed interest rate per annum																	10.75%
American Airlines, Inc. | Revolving Credit Facility
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, remaining borrowing capacity	400,000,000					400,000,000			400,000,000	400,000,000	400,000,000
American Airlines, Inc. | Revolving Credit Facility | Secured Debt | 2014 Credit Facilities
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, maximum borrowing capacity																						$ 1,200,000,000
Borrowings from credit facilities				$ 1,600,000,000
American Airlines, Inc. | Revolving Credit Facility | Secured Debt | April 2016 Credit Facilities
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, remaining borrowing capacity			0
Borrowings from credit facilities			450,000,000
American Airlines, Inc. | Revolving Credit Facility | Secured Debt | 2013 Credit Facilities
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, remaining borrowing capacity			0	$ 0
Borrowings from credit facilities			$ 750,000,000
American Airlines, Inc. | Line of Credit
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, remaining borrowing capacity	4,927,000,000					4,927,000,000			4,927,000,000	4,927,000,000	4,927,000,000
American Airlines, Inc. | Line of Credit | Treasury Loan Agreement, CARES Act
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, remaining borrowing capacity	$ 4,900,000,000					$ 4,900,000,000			$ 4,900,000,000	$ 4,900,000,000	4,900,000,000
Line of credit facility, maximum borrowing capacity																	$ 5,500,000,000
Borrowings from credit facilities											$ 550,000,000
American Airlines, Inc. | Line of Credit | Treasury Loan Agreement, CARES Act | Subsequent Event
Unusual or Infrequent Item, or Both [Line Items]
Line of credit facility, maximum borrowing capacity														$ 7,500,000,000
Warrants Tranche 1 | Payroll Support Program Promissory Note
Unusual or Infrequent Item, or Both [Line Items]
Warrant, number of shares of common stock (in shares) | shares																				6,700,000
Warrants Tranche 2 | Payroll Support Program Promissory Note
Unusual or Infrequent Item, or Both [Line Items]
Warrant, number of shares of common stock (in shares) | shares																			2,800,000
Warrants Tranche 3 | Payroll Support Program Promissory Note
Unusual or Infrequent Item, or Both [Line Items]
Warrant, number of shares of common stock (in shares) | shares		2,800,000					2,800,000
Warrants Tranche 4 | Payroll Support Program Promissory Note
Unusual or Infrequent Item, or Both [Line Items]
Warrant, number of shares of common stock (in shares) | shares																		1,400,000
Warrants Tranche 5 | Payroll Support Program Promissory Note
Unusual or Infrequent Item, or Both [Line Items]
Warrant, number of shares of common stock (in shares) | shares	400,000					400,000			400,000	400,000	400,000