INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

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

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

	2015			2014
Excess of tax over book depreciation	$	1,110		$	1,042
Other—net	23			22
Gross deferred tax liabilities	1,133			1,064
Mileage Plan	(208		)	(206		)
Inventory obsolescence	(22		)	(20		)
Deferred gains	(8		)	(10		)
Employee benefits	(167		)	(166		)
Fuel hedge contracts	(5		)	(5		)
Other—net	(41		)	(24		)
Gross deferred tax assets	(451		)	(431		)
Net deferred tax liabilities	$	682		$	633

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

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

	2015			2014		2013
Current tax expense:
Federal	$	397		$	229	$	145
State	30			27		17
Total current	427			256		162
Deferred tax expense:
Federal	60			103		131
State	(23		)	11		15
Total deferred	37			114		146
Income tax expense	$	464		$	370	$	308

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

Income tax expense reconciles to the amount computed by applying the U.S. federal rate of 35% to income before income tax and accounting change as follows (in millions):

	2015			2014			2013
Income before income tax	$	1,312		$	975		$	816
Expected tax expense	459			341			286
Nondeductible expenses	4			4			4
State income taxes	19			25			21
State income sourcing	(15		)	—			—
Other—net	(3		)	—			(3		)
Actual tax expense	$	464		$	370		$	308
Effective tax rate	35.4		%	37.9		%	37.7		%

Summary of Income Tax Contingencies [Table Text Block]

A summary of the Company's jurisdictions and the periods that are subject to examination are as follows:

Jurisdiction	Period
Federal	2012 to 2014
Alaska	2012 to 2014
California	2010 to 2014
Oregon	2003 to 2014*

*The 2003, 2004, 2008-2010 and 2011 Oregon tax returns are subject to examination only to the extent of net operating loss carryforwards from those years that were utilized in 2010 and later years.  

Changes in the liability for unrecognized tax benefits during 2015, 2014, and 2013 are as follows (in millions):

	2015		2014		2013
Balance at January 1,	$	3	$	2	$	1
Additions based on tax positions and settlements related to the current year	19		1		1
Balance at December 31,	$	22	$	3	$	2