OPERATING SEGMENT INFORMATION (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Operating revenues
Passenger, Mainline		$ 4,098	$ 3,939		$ 3,774
Passenger, Regional		908	854		805
Total passenger revenue		5,006	4,793		4,579
CPA revenues		0	0		0
Freight and mail		108	108		114
Other Net and Special Revenue		817	697		675
Total Operating Revenues		5,931	5,598		5,368
Operating expenses
Operating expenses, excluding fuel		3,751	3,346		2,988
Special items—merger-related costs and other		117	32		(30)
Economic fuel		831	954		1,418
Total Operating Expenses		4,582	4,300		4,406
Nonoperating Income (Expense)
Interest income		27	21		21
Interest expense		(55)	(42)		(48)
Other		24	35		40
Nonoperating Income (Expense) Total		(4)	14		13
Income (loss) before income tax		1,345	1,312		975
Depreciation		363	320		294
Capital expenditures		678	831		694
Total assets		9,962	6,530
Air Group Adjusted [Member]
Operating revenues
Passenger, Mainline	[1]	4,098	3,939		3,774
Passenger, Regional	[1]	908	854		805
Total passenger revenue	[1]	5,006	4,793		4,579
CPA revenues	[1]	0	0		0
Freight and mail	[1]	108	108		114
Other Net and Special Revenue	[1]	817	697		675
Total Operating Revenues	[1]	5,931	5,598		5,368
Operating expenses
Operating expenses, excluding fuel	[1]	3,634	3,314		3,018
Economic fuel	[1]	844	954		1,441
Total Operating Expenses	[1]	4,478	4,268		4,459
Nonoperating Income (Expense)
Interest income	[1]	27	21		21
Interest expense	[1]	(55)	(42)		(48)
Other	[1]	24	35		40
Nonoperating Income (Expense) Total	[1]	(4)	14		13
Income (loss) before income tax	[1]	1,449	1,344		922
Alaska Airlines [Member]
Nonoperating Income (Expense)
Depreciation	[2]	296	268		243
Capital expenditures	[2]	608	821		659
Total assets	[2]	15,260	8,127
Alaska Mainline [Member]
Operating revenues
Passenger, Mainline		4,098	3,939		3,774
Passenger, Regional		0	0		0
Total passenger revenue		4,098	3,939		3,774
CPA revenues		0	0		0
Freight and mail		104	103		109
Other Net and Special Revenue		738	621		592
Total Operating Revenues		4,940	4,663		4,475
Operating expenses
Operating expenses, excluding fuel		2,883	2,653		2,417
Economic fuel		719	823		1,251
Total Operating Expenses		3,602	3,476		3,668
Nonoperating Income (Expense)
Interest income		26	19		20
Interest expense		(42)	(28)		(32)
Other		19	28		39
Nonoperating Income (Expense) Total		3	19		27
Income (loss) before income tax		1,341	1,206		834
Alaska Regional [Member]
Operating revenues
Passenger, Mainline		0	0		0
Passenger, Regional		908	854		805
Total passenger revenue		908	854		805
CPA revenues		0	0		0
Freight and mail		5	5		5
Other Net and Special Revenue		74	72		78
Total Operating Revenues		987	931		888
Operating expenses
Operating expenses, excluding fuel		769	695		623
Economic fuel		125	131		190
Total Operating Expenses		894	826		813
Nonoperating Income (Expense)
Interest income		0	0		0
Interest expense		0	0		0
Other		0	0		(1)
Nonoperating Income (Expense) Total		0	0		(1)
Income (loss) before income tax		93	105		74
Horizon [Member]
Operating revenues
Passenger, Mainline		0	0		0
Passenger, Regional		0	0		0
Total passenger revenue		0	0		0
CPA revenues		424	408		371
Freight and mail		0	0		0
Other Net and Special Revenue		4	4		5
Total Operating Revenues		428	412		376
Operating expenses
Operating expenses, excluding fuel		407	375		349
Economic fuel		0	0		0
Total Operating Expenses		407	375		349
Nonoperating Income (Expense)
Interest income		1	0		0
Interest expense		(9)	(10)		(12)
Other		1	1		2
Nonoperating Income (Expense) Total		(7)	(9)		(10)
Income (loss) before income tax		14	28		17
Depreciation		67	52		51
Capital expenditures		70	10		35
Total assets		690	717
Parent [Member]
Nonoperating Income (Expense)
Total assets		(5,988)	(2,314)
Intersegment Eliminations
Operating revenues
Passenger, Mainline		0	0		0
Passenger, Regional		0	0		0
Total passenger revenue		0	0		0
CPA revenues		(424)	(408)		(371)
Freight and mail		(1)	0		0
Other Net and Special Revenue		1	0		0
Total Operating Revenues		(424)	(408)		(371)
Operating expenses
Operating expenses, excluding fuel		(425)	(409)		(371)
Economic fuel		0	0		0
Total Operating Expenses		(425)	(409)		(371)
Nonoperating Income (Expense)
Interest income		0	2		1
Interest expense		(4)	(4)		(4)
Other		4	6		0
Nonoperating Income (Expense) Total		0	4		(3)
Income (loss) before income tax		1	5		(3)
Special Charges [Member]
Operating revenues
Passenger, Mainline	[3]	0	0		0
Passenger, Regional	[3]	0	0		0
Total passenger revenue	[3]	0	0		0
CPA revenues	[3]	0	0		0
Freight and mail	[3]	0	0		0
Other Net and Special Revenue	[3]	0	0		0
Total Operating Revenues	[3]	0	0		0
Operating expenses
Operating expenses, excluding fuel		117	32	[3]	(30)	[3]
Economic fuel		(13)	0	[3]	(23)	[3]
Total Operating Expenses	[3]	104	32		(53)
Nonoperating Income (Expense)
Interest income	[3]	0	0		0
Interest expense	[3]	0	0		0
Other	[3]	0	0		0
Nonoperating Income (Expense) Total	[3]	0	0		0
Income (loss) before income tax	[3]	$ (104)	$ (32)		$ 53

[1] Year Ended December 31, 2014Mainline Regional Horizon Consolidating & Other(b) Air Group Adjusted(c) Special Items(d) ConsolidatedOperating revenues Passenger Mainline$3,774 $— $— $— $3,774 $— $3,774Regional— 805 — — 805 — 805Total passenger revenues3,774 805 — — 4,579 — 4,579CPA revenues— — 371 (371) — — —Freight and mail109 5 — — 114 — 114Other-net592 78 5 — 675 — 675Total operating revenues4,475 888 376 (371) 5,368 — 5,368 Operating expenses Operating expenses, excluding fuel2,417 623 349 (371) 3,018 (30) 2,988Fuel expense1,251 190 — — 1,441 (23) 1,418Total operating expenses3,668 813 349 (371) 4,459 (53) 4,406 Nonoperating income (expense) Interest income20 — — 1 21 — 21Interest expense(32) — (12) (4) (48) — (48)Other39 (1) 2 — 40 — 40 27 (1) (10) (3) 13 — 13Income (loss) before income tax$834 $74 $17 $(3) $922 $53 $975

[2] 2016 2015 2014Depreciation and amortization: Mainline$296 $268 $243Horizon67 52 51Consolidated$363 $320 $294 Capital expenditures: Mainline$608 $821 $659Horizon70 10 35Consolidated$678 $831 $694 Total assets at end of period: Mainline$15,260 $8,127 Horizon690 717 Consolidating & Other(5,988) (2,314) Consolidated$9,962 $6,530

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