GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - MAINTENANCE DEPOSITS (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Deposit Liability [Line Items]
Aircraft Maintenance Deposits	$ 56
Aircraft Maintenance Deposits, Current	42	$ 70
Aircraft Maintenance Deposits, Noncurrent	$ 14

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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1406
-Paragraph a
-Subparagraph (3)
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1406
-Paragraph a
-Subparagraph (4)
-Publisher SEC

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