OPERATING SEGMENT INFORMATION (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	$ 2,232	$ 2,196
Operating expenses
Operating Expenses, Excluding Fuel	1,833	1,717
Economic fuel	565	665
Total Operating Expenses	2,398	2,382
Nonoperating Income (Expense)
Interest income	17	17
Interest expense	(35)	(28)
Interest capitalized	6	7
Other—net	0	(9)
Nonoperating Income (Expense)	(12)	(13)
Costs and Expenses, Total	$ 2,398	$ 2,382
Pretax Margin, Adjusted	(7.00%)	(5.20%)
Pretax Margin, GAAP	(8.00%)	(9.10%)
Mileage Plan Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	$ 412	$ 386
Air Group Adjusted [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	2,232	2,196
Operating expenses
Operating Expenses, Excluding Fuel	1,799	1,653
Economic fuel	578	645
Total Operating Expenses	2,377	2,298
Nonoperating Income (Expense)
Nonoperating Income (Expense)	(12)	(13)
Income (loss) before income tax	(157)	(115)
Alaska Mainline [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	1,840	1,873
Operating expenses
Operating Expenses, Excluding Fuel	1,514	1,390
Economic fuel	485	561
Total Operating Expenses	1,999	1,951
Nonoperating Income (Expense)
Nonoperating Income (Expense)	(3)	(6)
Income (loss) before income tax	(162)	(84)
Alaska Regional [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	390	322
Operating expenses
Operating Expenses, Excluding Fuel	299	256
Economic fuel	93	85
Total Operating Expenses	392	341
Nonoperating Income (Expense)
Nonoperating Income (Expense)	0	0
Income (loss) before income tax	(2)	(19)
Horizon [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	104	78
Operating expenses
Operating Expenses, Excluding Fuel	88	84
Economic fuel	0	0
Total Operating Expenses	88	84
Nonoperating Income (Expense)
Nonoperating Income (Expense)	(11)	(8)
Income (loss) before income tax	5	(14)
Consolidating and Other [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	(102)	(77)
Operating expenses
Operating Expenses, Excluding Fuel	(102)	(77)
Economic fuel	0	(1)
Total Operating Expenses	(102)	(78)
Nonoperating Income (Expense)
Nonoperating Income (Expense)	2	1
Income (loss) before income tax	2	2
Special Charges [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Operating expenses
Operating Expenses, Excluding Fuel	34	64
Economic fuel	(13)	20
Total Operating Expenses	21	84
Nonoperating Income (Expense)
Nonoperating Income (Expense)	0	0
Income (loss) before income tax	(21)	(84)
Passenger [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	2,004	1,984
Passenger [Member] | Air Group Adjusted [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	2,004	1,984
Passenger [Member] | Alaska Mainline [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	1,629	1,673
Passenger [Member] | Alaska Regional [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	375	311
Passenger [Member] | Horizon [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Passenger [Member] | Consolidating and Other [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Passenger [Member] | Special Charges [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Capacity Purchase Agreements [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Capacity Purchase Agreements [Member] | Air Group Adjusted [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Capacity Purchase Agreements [Member] | Alaska Mainline [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Capacity Purchase Agreements [Member] | Alaska Regional [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Capacity Purchase Agreements [Member] | Horizon [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	104	78
Capacity Purchase Agreements [Member] | Consolidating and Other [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	(104)	(78)
Capacity Purchase Agreements [Member] | Special Charges [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Mileage plan other revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	164	154
Mileage plan other revenue [Member] | Mileage Plan Revenue [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	164	154
Mileage plan other revenue [Member] | Air Group Adjusted [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	164	154
Mileage plan other revenue [Member] | Alaska Mainline [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	149	143
Mileage plan other revenue [Member] | Alaska Regional [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	15	11
Mileage plan other revenue [Member] | Horizon [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Mileage plan other revenue [Member] | Consolidating and Other [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Mileage plan other revenue [Member] | Special Charges [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Cargo and Freight [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	64	58
Cargo and Freight [Member] | Air Group Adjusted [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	64	58
Cargo and Freight [Member] | Alaska Mainline [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	62	57
Cargo and Freight [Member] | Alaska Regional [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Cargo and Freight [Member] | Horizon [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	0	0
Cargo and Freight [Member] | Consolidating and Other [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	2	1
Cargo and Freight [Member] | Special Charges [Member]
Operating Revenues
Revenue from Contract with Customer, Excluding Assessed Tax	$ 0	$ 0