OPERATING SEGMENT INFORMATION - Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Segment Reporting Information [Line Items]
Total segment operating revenue	$ 3,704	$ 2,897	$ 6,841	$ 5,129
Wages and benefits	1,165	782	2,292	1,586
Aircraft maintenance	240	129	460	251
Aircraft rent	64	46	126	93
Landing fees and other rentals	278	173	520	338
Contracted services	146	106	291	203
Selling expenses	105	84	205	161
Depreciation and amortization	199	128	393	254
Food and beverage service	97	67	182	125
Other	247	186	508	391
Regional carrier expenses	69	64	133	118
Total Operating Expenses	3,427	2,575	6,761	4,973
Interest income	22	24	48	41
Interest expense	(66)	(36)	(132)	(71)
Other - net	(4)	0	(12)	0
Total Non-operating Expense	(39)	(6)	(75)	(18)
Income Before Income Tax	238	316	5	138
Reconciliation to Consolidated Income Before Income Tax:
Special items - operating	56	146	147	180
Total assets	19,885		19,885		$ 19,768
Capital expenditures	549	553	810	655
Passenger revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	3,355	2,651	6,163	4,655
Mileage Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	571	464	1,094	876
Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	139	72	261	136
Passenger | Passenger revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	3,355	2,651	6,163	4,655
Passenger | Mileage Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	361	290	677	538
Mileage plan other revenue | Mileage Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	210	174	417	338
Cargo and Freight | Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	139	72	261	136
Operating Segments
Segment Reporting Information [Line Items]
Total segment operating revenue	3,701	2,894	6,836	5,124
Wages and benefits	1,029	663	2,027	1,346
Variable incentive pay	56	46	112	83
Economic fuel	701	620	1,385	1,198
Aircraft maintenance	217	113	415	220
Aircraft rent	37	19	73	39
Landing fees and other rentals	225	134	422	262
Contracted services	178	131	348	251
Selling expenses	96	73	188	141
Depreciation and amortization	184	113	364	225
Food and beverage service	89	59	167	112
Other	214	158	445	335
Regional carrier expenses	371	329	716	637
Total Operating Expenses	3,397	2,458	6,662	4,849
Interest income	42	25	88	43
Interest expense	(77)	(26)	(155)	(51)
Other - net	6	7	15	11
Total Non-operating Expense	(29)	6	(52)	3
Income Before Income Tax	275	442	122	278
Operating Segments | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	2,373	2,417	4,347	4,257
Wages and benefits	752	663	1,473	1,346
Variable incentive pay	41	46	84	83
Economic fuel	437	520	856	1,005
Aircraft maintenance	136	113	259	220
Aircraft rent	21	19	42	39
Landing fees and other rentals	166	134	308	262
Contracted services	142	131	276	251
Selling expenses	67	73	129	141
Depreciation and amortization	124	113	246	225
Food and beverage service	60	59	115	112
Other	154	158	327	335
Regional carrier expenses	0	0	0	0
Total Operating Expenses	2,100	2,029	4,115	4,019
Interest income	40	25	83	43
Interest expense	(51)	(26)	(103)	(51)
Other - net	5	7	12	11
Total Non-operating Expense	(6)	6	(8)	3
Income Before Income Tax	267	394	224	241
Reconciliation to Consolidated Income Before Income Tax:
Total assets	24,460		24,460		24,664
Capital expenditures	330	529	422	581
Operating Segments | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	857	0	1,604	0
Wages and benefits	277	0	554	0
Variable incentive pay	15	0	28	0
Economic fuel	171	0	345	0
Aircraft maintenance	81	0	156	0
Aircraft rent	16	0	31	0
Landing fees and other rentals	59	0	114	0
Contracted services	36	0	72	0
Selling expenses	29	0	59	0
Depreciation and amortization	60	0	118	0
Food and beverage service	29	0	52	0
Other	60	0	118	0
Regional carrier expenses	0	0	0	0
Total Operating Expenses	833	0	1,647	0
Interest income	2	0	5	0
Interest expense	(26)	0	(52)	0
Other - net	1	0	3	0
Total Non-operating Expense	(23)	0	(44)	0
Income Before Income Tax	1	0	(87)	0
Reconciliation to Consolidated Income Before Income Tax:
Total assets	4,725		4,725		4,423
Capital expenditures	165	0	309	0
Operating Segments | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	471	477	885	867
Wages and benefits	0	0	0	0
Variable incentive pay	0	0	0	0
Economic fuel	93	100	184	193
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	371	329	716	637
Total Operating Expenses	464	429	900	830
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	7	48	(15)	37
Operating Segments | Passenger | Passenger revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	3,355	2,651	6,163	4,655
Operating Segments | Passenger | Passenger revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	2,132	2,188	3,889	3,817
Operating Segments | Passenger | Passenger revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	769	0	1,422	0
Operating Segments | Passenger | Passenger revenue | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	454	463	852	838
Operating Segments | Mileage plan other revenue | Mileage Plan Revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	210	174	417	338
Operating Segments | Mileage plan other revenue | Mileage Plan Revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	161	160	313	309
Operating Segments | Mileage plan other revenue | Mileage Plan Revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	32	0	71	0
Operating Segments | Mileage plan other revenue | Mileage Plan Revenue | Regional
Segment Reporting Information [Line Items]
Total segment operating revenue	17	14	33	29
Operating Segments | Cargo and Freight | Cargo and other revenue
Segment Reporting Information [Line Items]
Total segment operating revenue	136	69	256	131
Operating Segments | Cargo and Freight | Cargo and other revenue | Alaska Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	80	69	145	131
Operating Segments | Cargo and Freight | Cargo and other revenue | Hawaiian Airlines
Segment Reporting Information [Line Items]
Total segment operating revenue	56	0	111	0
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	5	5
Income Before Income Tax	20	15	33	22
Reconciliation to Consolidated Income Before Income Tax:
Total assets	(9,300)		(9,300)		$ (9,319)
Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment
Reconciliation to Consolidated Income Before Income Tax:
Aircraft fuel mark-to-market adjustment	1	5	4	18
Losses on foreign debt	(2)		(7)
Special items - operating	(56)	(146)	(147)	(180)
Segment Reporting, Reconciling Item, Corporate Nonsegment
Reconciliation to Consolidated Income Before Income Tax:
Capital expenditures	54	24	79	74
Segment Reporting, Reconciling Item, Corporate Nonsegment | Embraer E175 aircraft
Reconciliation to Consolidated Income Before Income Tax:
Capital expenditures	$ 46	$ 23	$ 69	$ 68