FLEET TRANSITION (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Sep. 30, 2022
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	$ 155,000,000		$ 376,000,000
Impairment Charges
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	0		70,000,000
Accelerated aircraft ownership expenses [Member]
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	80,000,000		123,000,000
Lease return costs and other expenses
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	75,000,000		183,000,000
Impairment Charges
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges		$ 70,000,000
Airbus Aircraft [Member]
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	137,000,000		285,000,000
Airbus Aircraft [Member] | Impairment Charges
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	0		0
Airbus Aircraft [Member] | Accelerated aircraft ownership expenses [Member]
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	62,000,000		102,000,000
Airbus Aircraft [Member] | Lease return costs and other expenses
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	75,000,000		183,000,000
Q400 Aircraft
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	18,000,000		91,000,000
Q400 Aircraft | Impairment Charges
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	0		70,000,000
Q400 Aircraft | Accelerated aircraft ownership expenses [Member]
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	18,000,000		21,000,000
Q400 Aircraft | Lease return costs and other expenses
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	$ 0		$ 0