OPERATING SEGMENT INFORMATION - Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Total segment operating revenue	$ 3,766	$ 3,072	$ 10,607	$ 8,201
Wages and benefits	1,226	883	3,518	2,469
Aircraft maintenance	238	140	698	391
Aircraft rent	64	49	190	142
Landing fees and other rentals	305	194	825	532
Contracted services	151	108	442	311
Selling expenses	107	82	312	243
Depreciation and amortization	203	139	596	393
Food and beverage service	100	69	282	194
Other	256	202	764	593
Regional carrier expenses	72	63	205	181
Total Operating Expenses	3,618	2,731	10,379	7,704
Interest income	23	28	71	69
Interest expense	(70)	(44)	(202)	(115)
Other - net	2	(4)	(10)	(4)
Total Non-operating Expense	(37)	(13)	(112)	(31)
Income Before Income Tax	111	328	116	466
Reconciliation to Consolidated Income Before Income Tax:
Special items - operating	64	74	211	254
Total assets	20,012		20,012		$ 19,768
Capital expenditures	222	265	1,032	920
Passenger revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	3,424	2,821	9,587	7,476
Loyalty Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	558	460	1,652	1,336
Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	142	80	403	216
Passenger | Passenger revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	3,424	2,821	9,587	7,476
Passenger | Loyalty Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	358	289	1,035	827
Loyalty program other | Loyalty Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	200	171	617	509
Cargo and Freight | Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	142	80	403	216
Operating Segments
Segment Reporting Information [Line Items]
Total segment operating revenue	3,763	3,069	10,599	8,193
Wages and benefits	1,072	747	3,099	2,093
Variable incentive pay	65	93	177	176
Economic fuel	761	628	2,146	1,826
Aircraft maintenance	218	126	633	346
Aircraft rent	36	22	109	61
Landing fees and other rentals	248	150	670	412
Contracted services	189	135	537	386
Selling expenses	98	72	286	213
Depreciation and amortization	186	124	550	349
Food and beverage service	91	62	258	174
Other	226	176	671	511
Regional carrier expenses	386	340	1,102	977
Total Operating Expenses	3,576	2,675	10,238	7,524
Interest income	46	30	134	73
Interest expense	(85)	(34)	(240)	(85)
Other - net	8	3	23	14
Total Non-operating Expense	(31)	(1)	(83)	2
Income Before Income Tax	156	393	278	671
Operating Segments | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	2,406	2,483	6,753	6,740
Wages and benefits	800	710	2,273	2,056
Variable incentive pay	48	93	132	176
Economic fuel	470	510	1,326	1,515
Aircraft maintenance	129	117	388	337
Aircraft rent	20	21	62	60
Landing fees and other rentals	182	142	490	404
Contracted services	152	130	428	381
Selling expenses	68	68	197	209
Depreciation and amortization	126	116	372	341
Food and beverage service	63	58	178	170
Other	157	170	484	505
Regional carrier expenses	0	0	0	0
Total Operating Expenses	2,215	2,135	6,330	6,154
Interest income	43	28	126	71
Interest expense	(54)	(28)	(157)	(79)
Other - net	7	3	19	14
Total Non-operating Expense	(4)	3	(12)	6
Income Before Income Tax	187	351	411	592
Reconciliation to Consolidated Income Before Income Tax:
Total assets	24,766		24,766		24,664
Capital expenditures	172	252	594	833
Operating Segments | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	857	95	2,461	95
Wages and benefits	272	37	826	37
Variable incentive pay	17	0	45	0
Economic fuel	188	23	533	23
Aircraft maintenance	89	9	245	9
Aircraft rent	16	1	47	1
Landing fees and other rentals	66	8	180	8
Contracted services	37	5	109	5
Selling expenses	30	4	89	4
Depreciation and amortization	60	8	178	8
Food and beverage service	28	4	80	4
Other	69	6	187	6
Regional carrier expenses	0	0	0	0
Total Operating Expenses	872	105	2,519	105
Interest income	3	2	8	2
Interest expense	(31)	(6)	(83)	(6)
Other - net	1	0	4	0
Total Non-operating Expense	(27)	(4)	(71)	(4)
Income Before Income Tax	(42)	(14)	(129)	(14)
Reconciliation to Consolidated Income Before Income Tax:
Total assets	4,646		4,646		4,423
Capital expenditures	50	2	359	2
Operating Segments | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	500	491	1,385	1,358
Wages and benefits	0	0	0	0
Variable incentive pay	0	0	0	0
Economic fuel	103	95	287	288
Aircraft maintenance	0	0	0	0
Aircraft rent	0	0	0	0
Landing fees and other rentals	0	0	0	0
Contracted services	0	0	0	0
Selling expenses	0	0	0	0
Depreciation and amortization	0	0	0	0
Food and beverage service	0	0	0	0
Other	0	0	0	0
Regional carrier expenses	386	340	1,102	977
Total Operating Expenses	489	435	1,389	1,265
Interest income	0	0	0	0
Interest expense	0	0	0	0
Other - net	0	0	0	0
Total Non-operating Expense	0	0	0	0
Income Before Income Tax	11	56	(4)	93
Operating Segments | Passenger | Passenger revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	3,424	2,821	9,587	7,476
Operating Segments | Passenger | Passenger revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	2,172	2,261	6,061	6,078
Operating Segments | Passenger | Passenger revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	768	84	2,190	84
Operating Segments | Passenger | Passenger revenue | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	484	476	1,336	1,314
Operating Segments | Loyalty program other | Loyalty Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	200	171	617	509
Operating Segments | Loyalty program other | Loyalty Plan Revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	155	151	468	460
Operating Segments | Loyalty program other | Loyalty Plan Revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	29	5	100	5
Operating Segments | Loyalty program other | Loyalty Plan Revenue | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	16	15	49	44
Operating Segments | Cargo and Freight | Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	139	77	395	208
Operating Segments | Cargo and Freight | Cargo and other revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	79	71	224	202
Operating Segments | Cargo and Freight | Cargo and other revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	60	6	171	6
Operating Segments | Cargo and Freight | Cargo and other revenue | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	0	0	0	0
Corporate And Eliminations
Segment Reporting Information [Line Items]
Total segment operating revenue	3	3	8	8
Income Before Income Tax	17	6	50	28
Reconciliation to Consolidated Income Before Income Tax:
Total assets	(9,400)		(9,400)		$ (9,319)
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment
Reconciliation to Consolidated Income Before Income Tax:
Aircraft fuel mark-to-market adjustment		4	4	22
Gains on foreign debt	2		(5)
Special items - operating	(64)	(75)	(211)	(255)
Segment Reporting, Reconciling Item, Corporate Nonsegment
Reconciliation to Consolidated Income Before Income Tax:
Capital expenditures	$ 0	$ 11	79	85
Segment Reporting, Reconciling Item, Corporate Nonsegment | Embraer E175 aircraft
Reconciliation to Consolidated Income Before Income Tax:
Capital expenditures			$ 69	$ 68