COMMITMENTS (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($) aircraft	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) aircraft	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Segment Reporting Information [Line Items]
Goodwill	$ 2,703		$ 2,703		$ 1,943
Total assets	19,559		19,559		14,613
Product Liability Contingency [Line Items]
Payments for Merger Related Costs			146
Special items - Impairment charges and other	$ 74	$ 156	$ 254	$ 406
Firm aircraft commitment
Unrecorded Unconditional Purchase Obligation [Line Items]
Committed to Purchase (in Aircraft) | aircraft	85		85
Aircraft purchase option
Unrecorded Unconditional Purchase Obligation [Line Items]
Committed to Purchase (in Aircraft) | aircraft	107		107
B737 MAX [Member] | Firm aircraft commitment
Unrecorded Unconditional Purchase Obligation [Line Items]
Committed to Purchase (in Aircraft) | aircraft	69		69
B737 MAX [Member] | Aircraft purchase option
Unrecorded Unconditional Purchase Obligation [Line Items]
Committed to Purchase (in Aircraft) | aircraft	105		105
E175 [Member] | Firm aircraft commitment
Unrecorded Unconditional Purchase Obligation [Line Items]
Committed to Purchase (in Aircraft) | aircraft	6		6
E175 [Member] | Aircraft purchase option
Unrecorded Unconditional Purchase Obligation [Line Items]
Committed to Purchase (in Aircraft) | aircraft	2		2
B787-9 | Firm aircraft commitment
Unrecorded Unconditional Purchase Obligation [Line Items]
Committed to Purchase (in Aircraft) | aircraft	10		10
B787-9 | Aircraft purchase option
Unrecorded Unconditional Purchase Obligation [Line Items]
Committed to Purchase (in Aircraft) | aircraft	0		0
Aircraft-related Commitments [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Remainder of 2023	$ 337		$ 337
2024	1,380		1,380
2025	1,620		1,620
2026	1,180		1,180
2027	0		0
Thereafter	0		0
Unrecorded Unconditional Purchase Obligation	4,517		4,517
CPA and Other [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Remainder of 2023	49		49
2024	204		204
2025	207		207
2026	213		213
2027	219		219
Thereafter	507		507
Unrecorded Unconditional Purchase Obligation	1,399		1,399
Wages and Benefits [Member]
Product Liability Contingency [Line Items]
Special items - Impairment charges and other			30	51
Integration costs
Product Liability Contingency [Line Items]
Special items - Impairment charges and other	90		128
Litigation
Product Liability Contingency [Line Items]
Special items - Impairment charges and other			45
Fleet transition - impairment [Member]
Product Liability Contingency [Line Items]
Special items - Impairment charges and other	(16)	$ 156	51	$ 355
Alaska Airlines [Member]
Segment Reporting Information [Line Items]
Goodwill	1,943		1,943		1,943
Total assets	20,911		20,911		19,937
Hawaiian Airlines
Segment Reporting Information [Line Items]
Goodwill	761		761		0
Total assets	5,000		$ 5,000		$ 0
Virgin Group trademark license agreement [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Loss Contingency, Damages Sought, Value	$ 8