OPERATING SEGMENT INFORMATION - Reportable Segments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Total segment operating revenue	$ 14,239	$ 11,735	$ 10,426
Wages and benefits	4,763	3,588	3,041
Variable incentive pay	268	358	200
Aircraft fuel	2,879	2,506	2,641
Aircraft maintenance	912	620	488
Aircraft rent	250	207	208
Landing fees and other rentals	1,109	781	680
Contracted services	590	444	389
Selling expenses	407	349	303
Depreciation and amortization	795	583	451
Food and beverage service	383	287	241
Other	1,058	854	729
Regional carrier expenses	272	243	218
Special items - operating	250	345	443
Total Operating Expenses	13,936	11,165	10,032
Interest income	94	101	80
Interest expense	(272)	(171)	(121)
Other	21	29	(12)
Special items - net non-operating	0	16	(18)
Total Non-operating Expense	(157)	(25)	(71)
Income Before Income Tax	146	545	323
Capital expenditures	1,657	1,349	1,673
Total assets	20,361	19,768
Goodwill	2,723	2,724
Passenger revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	12,835	10,654	9,526
Loyalty Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	2,282	1,913	1,682
Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	549	348	252
Passenger | Passenger revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	12,835	10,654	9,526
Passenger | Loyalty Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	1,427	1,180	1,034
Loyalty program other | Loyalty Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	855	733	648
Cargo and Freight | Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	549	348	252
Operating Segments | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	9,090	9,051	8,853
Wages and benefits	3,079	2,781	2,562
Variable incentive pay	182	318	175
Aircraft fuel	1,777	1,962	2,264
Aircraft maintenance	504	475	440
Aircraft rent	83	81	100
Landing fees and other rentals	661	555	539
Contracted services	572	511	492
Selling expenses	254	271	268
Depreciation and amortization	501	462	402
Food and beverage service	244	231	218
Other	692	680	625
Regional carrier expenses	0	0	0
Special items - operating	0	0	0
Total Operating Expenses	8,549	8,327	8,085
Interest income	176	113	95
Interest expense	(209)	(112)	(96)
Other	18	19	(14)
Special items - net non-operating		0	0
Total Non-operating Expense	(15)	20	(15)
Income Before Income Tax	526	744	753
Capital expenditures	1,098	1,226	1,473
Total assets	24,985	24,664
Goodwill	2,177	2,177
Operating Segments | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	3,283	869	0
Wages and benefits	1,110	299	0
Variable incentive pay	62	4	0
Aircraft fuel	723	195	0
Aircraft maintenance	321	82	0
Aircraft rent	59	18	0
Landing fees and other rentals	244	61	0
Contracted services	143	39	0
Selling expenses	118	40	0
Depreciation and amortization	232	64	0
Food and beverage service	108	28	0
Other	243	66	0
Regional carrier expenses	0	0	0
Special items - operating	0	0	0
Total Operating Expenses	3,363	896	0
Interest income	10	7	0
Interest expense	(122)	(37)	0
Other	3	(1)	0
Special items - net non-operating		0	0
Total Non-operating Expense	(109)	(31)	0
Income Before Income Tax	(189)	(58)	0
Capital expenditures	474	33	0
Total assets	4,911	4,423
Goodwill	546	547
Operating Segments | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	1,853	1,805	1,565
Wages and benefits	0	0	0
Variable incentive pay	0	0	0
Aircraft fuel	383	377	379
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	1,471	1,317	1,141
Special items - operating	0	0	0
Total Operating Expenses	1,854	1,694	1,520
Interest income	0	0	0
Interest expense	0	0	0
Other	0	0	0
Special items - net non-operating		0	0
Total Non-operating Expense	0	0	0
Income Before Income Tax	(1)	111	45
Operating Segments | Passenger | Passenger revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	8,132	8,151	8,010
Operating Segments | Passenger | Passenger revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	2,918	757	0
Operating Segments | Passenger | Passenger revenue | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	1,785	1,746	1,516
Operating Segments | Loyalty program other | Loyalty Plan Revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	653	621	599
Operating Segments | Loyalty program other | Loyalty Plan Revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	134	53	0
Operating Segments | Loyalty program other | Loyalty Plan Revenue | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	68	59	49
Operating Segments | Cargo and Freight | Cargo and other revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	305	279	244
Operating Segments | Cargo and Freight | Cargo and other revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	231	59	0
Operating Segments | Cargo and Freight | Cargo and other revenue | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	0	0	0
Consolidating & Other
Segment Reporting Information [Line Items]
Total segment operating revenue	13	10	8
Wages and benefits	574	508	479
Variable incentive pay	24	36	25
Aircraft fuel	(4)	(28)	(2)
Aircraft maintenance	87	63	48
Aircraft rent	108	108	108
Landing fees and other rentals	204	165	141
Contracted services	(125)	(106)	(103)
Selling expenses	35	38	35
Depreciation and amortization	62	57	49
Food and beverage service	31	28	23
Other	123	108	104
Regional carrier expenses	(1,199)	(1,074)	(923)
Special items - operating	250	345	443
Total Operating Expenses	170	248	427
Interest income	(92)	(19)	(15)
Interest expense	59	(22)	(25)
Other	0	11	2
Special items - net non-operating		16	(18)
Total Non-operating Expense	(33)	(14)	(56)
Income Before Income Tax	(190)	(252)	(475)
Total assets	(9,535)	(9,319)
Consolidating & Other | Passenger | Passenger revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	0	0	0
Consolidating & Other | Loyalty program other | Loyalty Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	0	0	0
Consolidating & Other | Cargo and Freight | Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	13	10	8
Segment Reporting, Reconciling Item, Corporate Nonsegment
Segment Reporting Information [Line Items]
Capital expenditures	85	90	200
Segment Reporting, Reconciling Item, Corporate Nonsegment | Embraer E175 aircraft
Segment Reporting Information [Line Items]
Capital expenditures	$ 69	$ 68	$ 179