FLEET TRANSITION (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	$ 481,000,000
Loss Contingency Accrual	37,000,000	$ 22,000,000
Loss Contingency, Loss in Period	15,000,000
Asset Impairment Charge [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	70,000,000
Accelerated Aircraft Ownership Expenses [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	173,000,000
Lease return costs and other expenses [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	238,000,000
Airbus
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	378,000,000
Airbus | Asset Impairment Charge [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	0
Airbus | Accelerated Aircraft Ownership Expenses [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	140,000,000
Airbus | Lease return costs and other expenses [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	238,000,000
Q400
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	103,000,000
Q400 | Asset Impairment Charge [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	70,000,000
Q400 | Accelerated Aircraft Ownership Expenses [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	33,000,000
Q400 | Lease return costs and other expenses [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairment Charges	$ 0