Debt - Summary of Long-Term Debt (Details) - USD ($)	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Long term debt	$ 31,580,000,000	$ 33,876,000,000
Less: unamortized debt discount, premiums and debt issuance costs	(386,000,000)	(513,000,000)
Less: current portion of long-term debt	(2,911,000,000)	(3,002,000,000)
Long-term debt, net	$ 28,283,000,000	30,361,000,000
Secured Debt \| Minimum
Debt Instrument [Line Items]
Fixed interest rate	4.00%
Secured Debt \| Maximum
Debt Instrument [Line Items]
Fixed interest rate	5.90%
Secured Debt \| Aircraft notes
Debt Instrument [Line Items]
Long term debt	$ 12,262,000,000	$ 13,293,000,000
Secured Debt \| Aircraft notes \| Minimum
Debt Instrument [Line Items]
Fixed interest rate	2.70%
Secured Debt \| Aircraft notes \| Maximum
Debt Instrument [Line Items]
Fixed interest rate	6.48%
Secured Debt \| Aircraft notes \| LIBOR \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	0.49%	0.49%
Secured Debt \| Aircraft notes \| LIBOR \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	2.25%	2.25%
Secured Debt \| MileagePlus Senior Secured Notes
Debt Instrument [Line Items]
Fixed interest rate	6.50%
Long term debt	$ 3,420,000,000	$ 3,800,000,000
Secured Debt \| MileagePlus Term Loan Facility
Debt Instrument [Line Items]
Fixed interest rate	10.00%
Long term debt	$ 2,700,000,000	$ 3,000,000,000
Secured Debt \| MileagePlus Term Loan Facility \| LIBOR \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate	5.25%	5.25%
Secured Debt \| 2026 and 2029 Notes
Debt Instrument [Line Items]
Long term debt	$ 4,000,000,000	$ 4,000,000,000
Secured Debt \| 2026 and 2029 Notes \| Minimum
Debt Instrument [Line Items]
Fixed interest rate	4.38%
Secured Debt \| 2026 and 2029 Notes \| Maximum
Debt Instrument [Line Items]
Fixed interest rate	4.63%
Secured Debt \| 2021 Term Loans
Debt Instrument [Line Items]
Fixed interest rate	8.11%
Long term debt	$ 4,913,000,000	$ 4,963,000,000
Secured Debt \| 2021 Term Loans \| LIBOR \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate	3.75%	3.75%
Unsecured
Debt Instrument [Line Items]
Fixed interest rate	4.25%
Unsecured \| Notes
Debt Instrument [Line Items]
Long term debt	$ 596,000,000	$ 1,041,000,000
Unsecured \| Notes \| Minimum
Debt Instrument [Line Items]
Fixed interest rate	4.88%
Unsecured \| Notes \| Maximum
Debt Instrument [Line Items]
Fixed interest rate	5.00%
Unsecured \| Other unsecured debt
Debt Instrument [Line Items]
Long term debt	$ 508,000,000	$ 598,000,000
Unsecured \| Other unsecured debt \| Minimum
Debt Instrument [Line Items]
Fixed interest rate	0.00%
Unsecured \| Other unsecured debt \| Maximum
Debt Instrument [Line Items]
Fixed interest rate	5.75%
Unsecured \| PSP Notes
Debt Instrument [Line Items]
Fixed interest rate	1.00%
Long term debt	$ 3,181,000,000
Aggregate principal amount	$ 1,500,000,000
Unsecured \| PSP Notes \| SOFR
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
Unsecured \| Payroll Support Program (PSP1) Note
Debt Instrument [Line Items]
Term of debt	10 years
Aggregate principal amount	$ 900,000,000
Unsecured \| PSP3 Note
Debt Instrument [Line Items]
Aggregate principal amount	$ 800,000,000

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt classified as noncurrent. Excludes lease obligation.

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