OPERATING SEGMENT INFORMATION - Reportable Segments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Total segment operating revenue	$ 11,735	$ 10,426	$ 9,646
Wages and benefits	3,588	3,041	2,640
Variable incentive pay	358	200	257
Aircraft maintenance	620	488	424
Aircraft rent	207	208	291
Landing fees and other rentals	781	680	581
Contracted services	444	389	329
Selling expenses	349	303	295
Depreciation and amortization	583	451	415
Food and beverage service	287	241	197
Other	854	729	717
Regional carrier expenses	243	218	182
Total Operating Expenses	11,165	10,032	9,576
Interest income	101	80	53
Interest expense	(171)	(121)	(108)
Other - net	0	(39)	50
Total Non-operating Income (Expense)	(25)	(71)	9
Income Before Income Tax	545	323	79
Reconciliation to Consolidated Income Before Income Tax
Special items - operating	345	443	580
Special items - net non-operating	16	(18)	0
Capital expenditures	1,349	1,673	1,671
Total assets	19,768	14,613
Goodwill	2,724	1,943
Passenger Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	10,654	9,526	8,808
Mileage Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	1,913	1,682	1,521
Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	348	252	248
Passenger | Passenger Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	10,654	9,526	8,808
Passenger | Mileage Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	1,180	1,034	931
Mileage Plan Services, Other | Mileage Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	733	648	590
Cargo and Freight | Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	348	252	248
Operating Segments
Segment Reporting Information [Line Items]
Total segment operating revenue	11,725	10,418	9,642
Wages and benefits	3,080	2,562	2,213
Variable incentive pay	322	175	229
Economic fuel	2,534	2,643	2,592
Aircraft maintenance	557	440	365
Aircraft rent	99	100	187
Landing fees and other rentals	657	559	461
Contracted services	550	492	382
Selling expenses	311	268	263
Depreciation and amortization	526	402	350
Food and beverage service	259	218	177
Other	746	625	589
Regional carrier expenses	1,276	1,121	1,085
Total Operating Expenses	10,917	9,605	8,893
Interest income	120	95	59
Interest expense	(149)	(96)	(94)
Other - net	18	(14)	65
Total Non-operating Income (Expense)	(11)	(15)	30
Income Before Income Tax	797	798	779
Operating Segments | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	9,051	8,853	8,081
Wages and benefits	2,781	2,562	2,213
Variable incentive pay	318	175	229
Economic fuel	1,962	2,264	2,195
Aircraft maintenance	475	440	365
Aircraft rent	81	100	187
Landing fees and other rentals	596	559	461
Contracted services	511	492	382
Selling expenses	271	268	263
Depreciation and amortization	462	402	350
Food and beverage service	231	218	177
Other	680	625	589
Regional carrier expenses	0	0	0
Total Operating Expenses	8,368	8,105	7,411
Interest income	113	95	59
Interest expense	(112)	(96)	(94)
Other - net	19	(14)	65
Total Non-operating Income (Expense)	20	(15)	30
Income Before Income Tax	703	733	700
Reconciliation to Consolidated Income Before Income Tax
Capital expenditures	1,226	1,473	1,544
Total assets	24,664	19,937
Goodwill	2,177	1,943
Operating Segments | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	869	0	0
Wages and benefits	299	0	0
Variable incentive pay	4	0	0
Economic fuel	195	0	0
Aircraft maintenance	82	0	0
Aircraft rent	18	0	0
Landing fees and other rentals	61	0	0
Contracted services	39	0	0
Selling expenses	40	0	0
Depreciation and amortization	64	0	0
Food and beverage service	28	0	0
Other	66	0	0
Regional carrier expenses	0	0	0
Total Operating Expenses	896	0	0
Interest income	7	0	0
Interest expense	(37)	0	0
Other - net	(1)	0	0
Total Non-operating Income (Expense)	(31)	0	0
Income Before Income Tax	(58)	0	0
Reconciliation to Consolidated Income Before Income Tax
Capital expenditures	33	0	0
Total assets	4,423	0
Goodwill	547	0
Operating Segments | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	1,805	1,565	1,561
Wages and benefits	0	0	0
Variable incentive pay	0	0	0
Economic fuel	377	379	397
Aircraft maintenance	0	0	0
Aircraft rent	0	0	0
Landing fees and other rentals	0	0	0
Contracted services	0	0	0
Selling expenses	0	0	0
Depreciation and amortization	0	0	0
Food and beverage service	0	0	0
Other	0	0	0
Regional carrier expenses	1,276	1,121	1,085
Total Operating Expenses	1,653	1,500	1,482
Interest income	0	0	0
Interest expense	0	0	0
Other - net	0	0	0
Total Non-operating Income (Expense)	0	0	0
Income Before Income Tax	152	65	79
Operating Segments | Passenger | Passenger Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	10,654	9,526	8,808
Operating Segments | Passenger | Passenger Revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	8,151	8,010	7,299
Operating Segments | Passenger | Passenger Revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	757	0	0
Operating Segments | Passenger | Passenger Revenue | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	1,746	1,516	1,509
Operating Segments | Mileage Plan Services, Other | Mileage Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	733	648	590
Operating Segments | Mileage Plan Services, Other | Mileage Plan Revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	621	599	538
Operating Segments | Mileage Plan Services, Other | Mileage Plan Revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	53	0	0
Operating Segments | Mileage Plan Services, Other | Mileage Plan Revenue | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	59	49	52
Operating Segments | Cargo and Freight | Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	338	244	244
Operating Segments | Cargo and Freight | Cargo and other revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	279	244	244
Operating Segments | Cargo and Freight | Cargo and other revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	59	0	0
Operating Segments | Cargo and Freight | Cargo and other revenue | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	0	0	0
Corporate And Eliminations
Segment Reporting Information [Line Items]
Total segment operating revenue	10	8	4
Income Before Income Tax	39	(16)	(44)
Reconciliation to Consolidated Income Before Income Tax
Total assets	(9,319)	(5,324)
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment
Reconciliation to Consolidated Income Before Income Tax
Aircraft fuel mark-to-market adjustment	28	2	(76)
Unrealized gain on foreign debt	10
Special items - operating	(345)	(443)	(580)
Special items - net non-operating	16	(18)
Segment Reporting, Reconciling Item, Corporate Nonsegment
Reconciliation to Consolidated Income Before Income Tax
Capital expenditures	90	200	$ 127
Segment Reporting, Reconciling Item, Corporate Nonsegment | Embraer E175 aircraft
Reconciliation to Consolidated Income Before Income Tax
Capital expenditures	$ 68	$ 179