INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2018

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

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



	2018			2017
Excess of tax over book depreciation	$	1,066		$	964
Intangibles—net	15			14
Other—net	43			88
Deferred tax liabilities	1,124			1,066

Mileage Plan™	(315		)	(337		)
Inventory obsolescence	(15		)	(16		)
Deferred gains	(5		)	(5		)
Employee benefits	(172		)	(154		)
Acquired net operating losses	(64		)	(127		)
Other—net	(43		)	(57		)
Deferred tax assets	(614		)	(696		)
Valuation allowance	2			—
Net deferred tax (assets) liabilities	$	512		$	370

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

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



	2018			2017			2016
Current income tax expense:
Federal	$	(5	)	$	127		$	392
State	9			35			48
Total current income tax expense	4			162			440

Deferred income tax expense (benefit):
Federal	125			(3		)	67
State	19			40			12
Total deferred income tax expense (benefit)	144			37			79
Income tax expense	$	148		$	199		$	519

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



	2018			2017			2016
Income before income tax	$	585		$	1,159		$	1,316

Expected tax expense	123			406			461
Nondeductible expenses	9			5			20
State income taxes	21			28			27
State income sourcing	—			9			12
Tax law changes	(7		)	(237		)	—
Other—net	2			(12		)	(1		)
Actual tax expense	$	148		$	199		$	519

Effective tax rate	25.3		%	17.2		%	39.4		%

Summary of Income Tax Contingencies [Table Text Block]

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

Changes in the liability for gross unrecognized tax benefits during 2018, 2017 and 2016 are as follows (in milli

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 2017
Alaska	2012 to 2017
California	2007 to 2017
Oregon	2003 to 2017

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

Changes in the liability for gross unrecognized tax benefits during 2018, 2017 and 2016 are as follows (in millions):



	2018			2017			2016
Balance at January 1,	$	43		$	40		$	32
Additions related to prior years	1			16			—
Releases related to prior years	(4		)	(2		)	—
Additions related to current year activity	2			2			—
Additions from acquisitions	—			—			8
Releases due to settlements	(1		)	(11		)	—
Releases due to lapse of statute of limitations	(1		)	(2		)	—
Balance at December 31,	$	40		$	43		$	40