INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

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

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

	2019		2018
Excess of tax over book depreciation	$	1,233	$	1,066
Intangibles - net	16		15
Operating lease liabilities	416		—
Other - net	58		43
Deferred tax liabilities	1,723		1,124
Mileage Plan™	(337)		(315)
Inventory obsolescence	(15)		(15)
Employee benefits	(179)		(172)
Acquired net operating losses	(13)		(64)
Operating lease assets	(417)		—
Other - net	(48)		(48)
Deferred tax assets	(1,009)		(614)
Valuation allowance	1		2
Net deferred tax liabilities	$	715	$	512

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

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

	2019		2018		2017
Current income tax expense (benefit):
Federal	$	26	$	(5)	$	127
State	13		9		35
Total current income tax expense	39		4		162
Deferred income tax expense (benefit):
Federal	175		125		(3)
State	33		19		40
Total deferred income tax expense (benefit)	208		144		37
Income tax expense	$	247	$	148	$	199

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

	2019			2018			2017
Income before income tax	$	1,016		$	585		$	1,159
Expected tax expense	213			123			406
Nondeductible expenses	9			9			5
State income taxes	36			21			28
State income sourcing	1			—			9
Tax law changes	(9)			(7)			(237)
Other - net	(3)			2			(12)
Actual tax expense	$	247		$	148		$	199
Effective tax rate	24.3		%	25.3		%	17.2		%

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	2007 to 2018
Alaska	2015 to 2018
California	2007 to 2018
Oregon	2003 to 2018

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

Changes in the liability for gross unrecognized tax benefits during 2019, 2018 and 2017 are as follows (in millions):

	2019		2018		2017
Balance at January 1,	$	40	$	43	$	40
Additions related to prior years	—		1		16
Releases related to prior years	(1)		(4)		(2)
Additions related to current year activity	2		2		2
Releases due to settlements	—		(1)		(11)
Releases due to lapse of statute of limitations	(1)		(1)		(2)
Balance at December 31,	$	40	$	40	$	43