FLEET TRANSITION (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2022
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	$ 146,000,000		$ 221,000,000
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	43,000,000		43,000,000
Lease return costs and other expenses
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	103,000,000		108,000,000
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	143,000,000		148,000,000
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	40,000,000		40,000,000
Airbus Aircraft [Member] | Lease return costs and other expenses
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	103,000,000		108,000,000
Q400 Aircraft
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	3,000,000		73,000,000
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	3,000,000		3,000,000
Q400 Aircraft | Lease return costs and other expenses
Impaired Long-Lived Assets [Line Items]
Asset Impairment Charges	$ 0		$ 0