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DEBT - Narrative (Details)					12 Months Ended
DEBT - Narrative (Details)	Nov. 01, 2024 USD ($)	Jul. 02, 2024 USD ($)	Feb. 22, 2024 USD ($)	Feb. 15, 2024 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Aug. 05, 2024 USD ($) series aircraft	Apr. 16, 2024 USD ($)
Debt Instrument [Line Items]
Repayments of long-term debt					$ 10,138,000,000	$ 4,248,000,000	$ 4,011,000,000
Unrestricted liquidity required for credit agreement					$ 2,000,000,000
Minimum ratio of appraised value of collateral for Credit Agreement					1.6
Secured Debt \| Term Loan Facility
Debt Instrument [Line Items]
Repayments of long-term debt		$ 1,800,000,000				$ 1,000,000,000
Proceeds from issuance of debt			$ 2,500,000,000
Secured Debt \| 2021 Term Loans
Debt Instrument [Line Items]
Repayments of long-term debt			$ 1,370,000,000
Percent spread on variable rate					2.00%
Secured Debt \| 2024 Term Loans
Debt Instrument [Line Items]
Repayments of long-term debt	$ 400,000,000
Stated interest rate					6.63%
Secured Debt \| Aircraft Purchase Financing
Debt Instrument [Line Items]
Aggregate principal amount of debt								$ 1,400,000,000
Number of aircrafts financed \| aircraft								48
Number of indenture note series \| series								2
Secured Debt \| Series AA
Debt Instrument [Line Items]
Stated interest rate								5.45%
Aggregate principal amount of debt								$ 969,000,000
Secured Debt \| Series A
Debt Instrument [Line Items]
Stated interest rate								5.875%
Aggregate principal amount of debt								$ 385,000,000
Secured Debt \| 2026 Notes
Debt Instrument [Line Items]
Stated interest rate					4.375%
Secured Debt \| 2029 Notes
Debt Instrument [Line Items]
Stated interest rate					4.625%
Secured Debt \| Aircraft Purchase Financing
Debt Instrument [Line Items]
Proceeds from issuance of debt					$ 1,400,000,000
Secured Debt \| Minimum \| Aircraft Purchase Financing
Debt Instrument [Line Items]
Percent spread on variable rate					6.17%
Secured Debt \| Maximum \| Aircraft Purchase Financing
Debt Instrument [Line Items]
Percent spread on variable rate					6.51%
Secured Debt \| Secured Overnight Financing Rate (SOFR) \| 2024 Term Loans
Debt Instrument [Line Items]
Percent spread on variable rate	2.00%		2.75%
Debt instrument, interest rate floor			0.00%
Secured Debt \| Other Market Rates \| 2024 Term Loans
Debt Instrument [Line Items]
Percent spread on variable rate	1.00%		1.75%
Debt instrument, interest rate floor			1.00%
Secured Debt \| Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, increase (decrease) in maximum borrowing capacity				$ 1,115,000,000					$ 100,000,000
Maximum borrowing capacity				$ 2,865,000,000					2,965,000,000
Maximum borrowing capacity of portion involving extension of maturity									150,000,000
Undrawn and available amount under revolving credit facility					$ 2,965,000,000
Secured Debt \| Revolving Credit Facility \| Extending Lenders
Debt Instrument [Line Items]
Maximum borrowing capacity									2,950,000,000
Secured Debt \| Revolving Credit Facility \| Non-Extending Lenders
Debt Instrument [Line Items]
Maximum borrowing capacity									$ 15,000,000
Secured Debt \| Revolving Credit Facility \| Non-Extending Lenders \| Secured Overnight Financing Rate (SOFR) \| Minimum
Debt Instrument [Line Items]
Percent spread on variable rate				3.00%
Secured Debt \| Revolving Credit Facility \| Non-Extending Lenders \| Secured Overnight Financing Rate (SOFR) \| Maximum
Debt Instrument [Line Items]
Percent spread on variable rate				3.50%
Secured Debt \| Revolving Credit Facility \| Non-Extending Lenders \| Other Market Rates \| Minimum
Debt Instrument [Line Items]
Percent spread on variable rate				2.00%
Secured Debt \| Revolving Credit Facility \| Non-Extending Lenders \| Other Market Rates \| Maximum
Debt Instrument [Line Items]
Percent spread on variable rate				2.50%