EMPLOYEE BENEFIT PLANS  - Narrative (Details)	12 Months Ended
	Dec. 31, 2025 USD ($) plan	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of qualified defined benefit plans | plan	5
Number of defined contribution plans | plan	12
Expected required contributions, next fiscal year	$ 71,000,000
Total expense for the defined-contribution plans	348,000,000	$ 256,000,000	$ 203,000,000
Variable incentive pay	$ 268,000,000	358,000,000	200,000,000
Operational Performance Rewards Program entitles all Air Group employees to maximum quarterly payouts (in dollars per quarter)	450
Alaska Air Group
Defined Benefit Plan Disclosure [Line Items]
Number of qualified defined benefit plans | plan	4
Hawaiian Holdings, Inc.
Defined Benefit Plan Disclosure [Line Items]
Number of qualified defined benefit plans | plan	1
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 2,500,000,000	2,400,000,000
Net benefit cost	22,000,000	26,000,000	46,000,000
Total plan assets	2,491,000,000	2,307,000,000	2,023,000,000
Benefit obligation	2,524,000,000	2,462,000,000	$ 2,183,000,000
Unfunded status	(33,000,000)	$ (155,000,000)
Future benefits expected to be paid, year one	172,000,000
Future benefits expected to be paid, year two	187,000,000
Future benefits expected to be paid, year three	195,000,000
Future benefits expected to be paid, year four	196,000,000
Future benefits expected to be paid, year five	202,000,000
Future benefits expected to be paid, years 2031 through 2035	$ 1,022,000,000
Pension Plan | Minimum
Defined Benefit Plan Disclosure [Line Items]
Discount rates (in percent)	5.36%	5.62%
Pension Plan | Maximum
Defined Benefit Plan Disclosure [Line Items]
Discount rates (in percent)	5.58%	5.71%
Post-retirement Medical Benefits | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Number defined benefit postretirement and medical life insurance plans | plan	4
Net benefit cost	$ 17,000,000	$ 0
Total plan assets	51,000,000	48,000,000
Benefit obligation	177,000,000	159,000,000
Unfunded status	(126,000,000)	(111,000,000)
Future benefits expected to be paid, year one	11,000,000
Future benefits expected to be paid, year two	11,000,000
Future benefits expected to be paid, year three	11,000,000
Future benefits expected to be paid, year four	12,000,000
Future benefits expected to be paid, year five	13,000,000
Future benefits expected to be paid, years 2031 through 2035	76,000,000
Post-retirement Medical Benefits | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation	$ 112,000,000	$ 93,000,000
Post-retirement Medical Benefits | Minimum | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rates (in percent)	5.40%	5.61%
Post-retirement Medical Benefits | Maximum | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rates (in percent)	5.58%	5.70%
Postretirement Health Coverage
Defined Benefit Plan Disclosure [Line Items]
Total liability net of a prefunded trust account	$ 94,000,000	$ 86,000,000
Prefunded trust account	$ 16,000,000	$ 13,000,000