INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2023

Income Tax Disclosure [Abstract]

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

Deferred tax (assets) and liabilities comprise the following (in millions):

	2023		2022
Excess of tax over book depreciation	$	1,605	$	1,312
Intangibles - net	16		17
Operating lease assets	292		356
Other - net	3		49
Deferred tax liabilities	1,916		1,734
Mileage Plan	(455)		(436)
Inventory obsolescence	(23)		(21)
Employee benefits	(159)		(145)
Net operating losses	(166)		(28)
Operating lease liabilities	(329)		(392)
Leasehold maintenance	(28)		(67)
Other - net	(77)		(88)
Deferred tax assets	(1,237)		(1,177)
Valuation allowance	16		17
Net deferred tax liabilities	$	695	$	574

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

The components of income tax expense are as follows (in millions): 

	2023		2022		2021
Current income tax (benefit) expense:
Federal	$	(3)	$	(11)	$	40
State	(4)		(3)		16
Total current income tax (benefit) expense	(7)		(14)		56
Deferred income tax expense:
Federal	82		32		80
State	13		3		15
Total deferred income tax expense	95		35		95
Income tax expense	$	88	$	21	$	151

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	2023			2022			2021
Income before income tax	$	323		$	79		$	629
Expected tax expense	68			17			132
Nondeductible expenses	14			11			10
State income tax expense	17			5			20
Tax law changes	—			—			(14)
State income sourcing	(5)			(2)			—
Valuation allowance	(1)			(4)			1
Tax credits	(3)			(5)			(2)
Uncertain tax positions	(5)			(1)			3
Other - net	3			—			1
Actual tax expense	$	88		$	21		$	151
Effective tax rate(a)	27.1		%	26.2		%	24.0		%

Summary of Income Tax Contingencies [Table Text Block]

The Company has identified its federal tax return and its state tax returns in Alaska, Oregon and California as “major” tax jurisdictions. A summary of the Company's jurisdictions and the periods that are subject to examination are as follows:

Jurisdiction	Period
Federal	2020 to 2022
Alaska	2018 to 2022
California	2007 to 2022
Oregon	2015 to 2022

Certain tax years are open to the extent of net operating loss carryforwards.

Changes in the liability for gross unrecognized tax benefits during 2023, 2022 and 2021 are as follows (in millions):

	2023		2022		2021
Balance at January 1	$	21	$	41	$	35
Additions related to prior years	—		—		3
Releases related to prior years	—		(1)		—
Additions related to current year activity	9		1		3
Releases due to settlements	(3)		(20)		—
Releases due to lapse of statute of limitations	(2)		—		—
Balance at December 31	$	25	$	21	$	41