Number of Aircraft, Secured Debt Transactions

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The carrying amount, as of the date of the latest financial statement presented, of flight equipment which are owned but transferred to serve as collateral for the payment of the related debt obligation, primarily a secured borrowing or repurchase agreement, and for which the transferee is not permitted to sell or re-pledge them to an unrelated party.

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Scheduled maturities, Remainder of Fiscal Year, short-term borrowings, long-term debt, and finance lease obligations

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Scheduled maturities, Year 2, short-term borrowings, long-term debt, and finance lease obligations

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Scheduled maturities, Year 3, short-term borrowings, long-term debt, and finance lease obligations

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Scheduled maturities, Year 4, short-term borrowings, long-term debt, and finance lease obligations

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Scheduled maturities, Year 5, short-term borrowings, long-term debt, and finance lease obligations

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Scheduled maturities, after Year 5, short-term borrowings, long-term debt, and finance lease obligations

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

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The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

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

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

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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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The effective interest rate at the end of the reporting period.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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Amount of cash outflow for short-term and long-term debt and lease obligation.

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, maximum month-end borrowings during the period.

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Long-term Debt, Short-term Borrowings and Finance Lease Obligations (Details) - USD ($)	1 Months Ended	3 Months Ended	9 Months Ended
	May 08, 2020	Sep. 30, 2020	Sep. 30, 2020	Apr. 23, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Reduction in outstanding debt and capital lease obligations			$ 1,300,000,000
Value of aircraft, engines and other equipment and facilities which were pledged as security under various loan agreements		$ 6,200,000,000	6,200,000,000
Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year		95,000,000	95,000,000
Long-term debt, maturities, repayments of principal in Year Two		438,000,000	438,000,000
Long-term debt, maturities, repayments of principal in Year Three		417,000,000	417,000,000
Long-term debt, maturities, repayments of principal in Year Four		1,100,000,000	1,100,000,000
Long-term debt, maturities, repayments of principal in Year Five		966,000,000	966,000,000
Long-term debt, maturities, repayments of principal after Year Five		1,900,000,000	1,900,000,000
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		4,774,000,000	4,774,000,000		$ 2,245,000,000
Estimated Fair Value, Total		4,578,000,000	4,578,000,000		2,367,000,000
Long-term Debt [Member]
Carrying amounts and estimated fair values of long-term debt
Debt Instrument, Face Amount		923,000,000	923,000,000
Public Debt Fixed Rate Special Facility Bonds Due Through Two Thousand Thirty Six [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		42,000,000	42,000,000		42,000,000
Estimated Fair Value, Total		43,000,000	43,000,000		46,000,000
Fixed rate enhanced equipment notes, due through 2032, 2019-1 AA [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		574,000,000	574,000,000		581,000,000
Estimated Fair Value, Total		414,000,000	414,000,000		586,000,000
Fixed rate enhanced equipment notes, due through 2028, 2019-1 A [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		179,000,000	179,000,000		181,000,000
Estimated Fair Value, Total		146,000,000	146,000,000		186,000,000
Fixed rate enhanced equipment notes, due through 2027, 2019-1 B [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		114,000,000	114,000,000		0
Estimated Fair Value, Total		142,000,000	142,000,000		0
Fixed rate enhanced equipment notes, due through 2027, 2019-1 B [Member] \| Long-term Debt [Member]
Carrying amounts and estimated fair values of long-term debt
Debt Instrument, Face Amount		$ 115,000,000	$ 115,000,000
Debt Instrument, Interest Rate, Stated Percentage		8.00%	8.00%
Fixed rate enhanced equipment notes, due through 2032, 2020-1 A [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		$ 628,000,000	$ 628,000,000		0
Estimated Fair Value, Total		611,000,000	611,000,000		0
Fixed rate enhanced equipment notes, due through 2032, 2020-1 A [Member] \| Long-term Debt [Member]
Carrying amounts and estimated fair values of long-term debt
Debt Instrument, Face Amount		$ 636,000,000	$ 636,000,000
Debt Instrument, Interest Rate, Stated Percentage		4.00%	4.00%
Fixed rate enhanced equipment notes, due through 2028, 2020-1 B [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		$ 170,000,000	$ 170,000,000		0
Estimated Fair Value, Total		213,000,000	213,000,000		0
Fixed rate enhanced equipment notes, due through 2028, 2020-1 B [Member] \| Long-term Debt [Member]
Carrying amounts and estimated fair values of long-term debt
Debt Instrument, Face Amount		$ 172,000,000	$ 172,000,000
Debt Instrument, Interest Rate, Stated Percentage		7.75%	7.75%
Fixed rate enhanced equipment notes, 2020-1A and B [Member] \| Long-term Debt [Member]
Carrying amounts and estimated fair values of long-term debt
Debt Instrument, Face Amount		$ 808,000,000	$ 808,000,000
Non Public Debt Fixed Rate Enhanced Equipment Notes Due Through Two Thousand And Twenty Three [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		114,000,000	114,000,000		133,000,000
Estimated Fair Value, Total		115,000,000	115,000,000		141,000,000
Non Public Debt Floating Rate Equipment Notes Due Through Two Thousand And Twenty Eight [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		164,000,000	164,000,000		201,000,000
Estimated Fair Value, Total		150,000,000	150,000,000		207,000,000
Non Public Debt Fixed Rate Equipment Notes Due Through Two Thousand Twenty Eight [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		935,000,000	935,000,000		1,107,000,000
Estimated Fair Value, Total		920,000,000	920,000,000		1,201,000,000
Non Public Debt Floating Rate Term Loan Credit Facility Due Through 2024 [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		709,000,000	709,000,000		0
Estimated Fair Value, Total		750,000,000	750,000,000		0
Non Public Debt Unsecured CARES Act Payroll Support Program loan due through 2025 [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		259,000,000	259,000,000		0
Estimated Fair Value, Total		192,000,000	192,000,000		0
Non Public Debt Secured CARES Act Loan due through 2025 [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		105,000,000	105,000,000		0
Estimated Fair Value, Total		100,000,000	100,000,000		0
Non Public Debt Sale Leaseback Transactions due through 2024 [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		235,000,000	235,000,000		0
Estimated Fair Value, Total		262,000,000	262,000,000		0
Non Public Debt Citibank Line of Credit due through 2023 [Member]
Carrying amounts and estimated fair values of long-term debt
Long-term Debt		546,000,000	546,000,000		0
Estimated Fair Value, Total		$ 520,000,000	$ 520,000,000		0
Airbus A321 [Member] \| Long-term Debt [Member]
Carrying amounts and estimated fair values of long-term debt
Secured Debt		49	49
Airbus A321 [Member] \| Fixed rate enhanced equipment notes, due through 2027, 2019-1 B [Member] \| Long-term Debt [Member]
Carrying amounts and estimated fair values of long-term debt
Secured Debt		25	25
Airbus A321 [Member] \| Fixed rate enhanced equipment notes, 2020-1A and B [Member] \| Long-term Debt [Member]
Carrying amounts and estimated fair values of long-term debt
Secured Debt		24	24
Barclays [Member] \| Non Public Debt Floating Rate Term Loan Credit Facility Due Through 2024 [Member] \| Long-term Debt [Member]
Carrying amounts and estimated fair values of long-term debt
Debt Instrument, Face Amount		$ 750,000,000	$ 750,000,000
US Department of Treasury [Member] \| Non Public Debt Secured CARES Act Loan due through 2025 [Member] \| Long-term Debt [Member]
Carrying amounts and estimated fair values of long-term debt
Debt Instrument, Face Amount		115,000,000	115,000,000
US Department of Treasury [Member] \| Unsecured Debt [Member]
Carrying amounts and estimated fair values of long-term debt
Debt Instrument, Face Amount		8,000,000	8,000,000	$ 251,000,000
Debt Instrument, Interest Rate, Stated Percentage				1.00%
Long-term Debt, Term				10 years
Citibank [Member] \| Non Public Debt Citibank Line of Credit due through 2023 [Member] \| Line of Credit [Member]
Carrying amounts and estimated fair values of long-term debt
Line of Credit, Current		550,000,000	550,000,000
Morgan Stanley [Member]
Carrying amounts and estimated fair values of long-term debt
Line of Credit, Current		$ 0	$ 0		$ 0
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] \| US Department of Treasury [Member] \| Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.00%
London Interbank Offered Rate (LIBOR) [Member] \| Non Public Debt Secured CARES Act Loan due through 2025 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis			LIBOR (or another rate based on certain market interest rates, plus a margin of 1% per annum, in each case with a floor of 0%), plus a margin of 2.75% per annum
London Interbank Offered Rate (LIBOR) [Member] \| Barclays [Member] \| Non Public Debt Floating Rate Term Loan Credit Facility Due Through 2024 [Member] \| Long-term Debt [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis			LIBOR (subject to a 1.00% floor), or at our election another rate, in each case, plus a specified margin
Carrying amounts and estimated fair values of long-term debt
Debt Instrument, Interest Rate, Stated Percentage		6.25%	6.25%
London Interbank Offered Rate (LIBOR) [Member] \| Citibank [Member] \| Non Public Debt Citibank Line of Credit due through 2023 [Member] \| Line of Credit [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis			LIBOR, plus a margin
Carrying amounts and estimated fair values of long-term debt
Line of Credit Facility, Interest Rate During Period		2.22%	2.22%
Short-term Debt [Member] \| Morgan Stanley [Member]
Debt Instrument [Line Items]
Repayments of Debt		$ 998,000,000
Short-term Debt, Fair Value			$ 0
Carrying amounts and estimated fair values of long-term debt
Debt Instrument, Face Amount		1,000,000,000.0	$ 1,000,000,000.0
Short-term Debt [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Morgan Stanley [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis			LIBOR (but not less than 1% per annum), plus a margin
Line of Credit [Member] \| Morgan Stanley [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 200,000,000	$ 200,000,000
Line of Credit [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Morgan Stanley [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis			LIBOR, plus a margin