OPERATING SEGMENT INFORMATION (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) segment	Mar. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of operating airlines | segment	3
Operating revenues
Passenger, Mainline	$ 1,272	$ 927
Passenger, Regional	212	206
Total passenger revenue	1,484	1,133
CPA revenues	0	0
Freight and mail	24	24
Other - net revenue	241	190
Total Operating Revenues	1,749	1,347
Operating expenses
Operating expenses, excluding fuel	1,244	890
Economic fuel	339	167
Total Operating Expenses	1,583	1,057
Nonoperating Income (Expense)
Interest income	7	6
Interest expense	(25)	(13)
Other	4	9
Nonoperating Income (Expense) Total	(14)	2
Income before income tax	152	292
Air Group Adjusted [Member]
Operating revenues
Passenger, Mainline	1,272	927
Passenger, Regional	212	206
Total passenger revenue	1,484	1,133
CPA revenues	0	0
Freight and mail	24	24
Other - net revenue	241	190
Total Operating Revenues	1,749	1,347
Operating expenses
Operating expenses, excluding fuel	1,204	890
Economic fuel	329	169
Total Operating Expenses	1,533	1,059
Nonoperating Income (Expense)
Interest income	7	6
Interest expense	(25)	(13)
Other	4	9
Nonoperating Income (Expense) Total	(14)	2
Income before income tax	202	290
Alaska Mainline [Member]
Operating revenues
Passenger, Mainline	1,272	927
Passenger, Regional	0	0
Total passenger revenue	1,272	927
CPA revenues	0	0
Freight and mail	23	23
Other - net revenue	222	172
Total Operating Revenues	1,517	1,122
Operating expenses
Operating expenses, excluding fuel	998	701
Economic fuel	292	144
Total Operating Expenses	1,290	845
Nonoperating Income (Expense)
Interest income	7	6
Interest expense	(22)	(12)
Other	3	7
Nonoperating Income (Expense) Total	(12)	1
Income before income tax	215	278
Alaska Regional [Member]
Operating revenues
Passenger, Mainline	0	0
Passenger, Regional	212	206
Total passenger revenue	212	206
CPA revenues	0	0
Freight and mail	1	1
Other - net revenue	17	17
Total Operating Revenues	230	224
Operating expenses
Operating expenses, excluding fuel	200	186
Economic fuel	36	25
Total Operating Expenses	236	211
Nonoperating Income (Expense)
Interest income	0	0
Interest expense	0	0
Other	0	0
Nonoperating Income (Expense) Total	0	0
Income before income tax	$ (6)	13
Horizon [Member]
Segment Reporting Information [Line Items]
Capacity purchase arrangements	100.00%
Operating revenues
Passenger, Mainline	$ 0	0
Passenger, Regional	0	0
Total passenger revenue	0	0
CPA revenues	97	103
Freight and mail	0	0
Other - net revenue	1	1
Total Operating Revenues	98	104
Operating expenses
Operating expenses, excluding fuel	103	105
Economic fuel	0	0
Total Operating Expenses	103	105
Nonoperating Income (Expense)
Interest income	0	0
Interest expense	(2)	(1)
Other	0	0
Nonoperating Income (Expense) Total	(2)	(1)
Income before income tax	(7)	(2)
Intersegment Elimination [Member]
Operating revenues
Passenger, Mainline	0	0
Passenger, Regional	0	0
Total passenger revenue	0	0
CPA revenues	(97)	(103)
Freight and mail	0	0
Other - net revenue	1	0
Total Operating Revenues	(96)	(103)
Operating expenses
Operating expenses, excluding fuel	(97)	(102)
Economic fuel	1	0
Total Operating Expenses	(96)	(102)
Nonoperating Income (Expense)
Interest income	0	0
Interest expense	(1)	0
Other	1	2
Nonoperating Income (Expense) Total	0	2
Income before income tax	0	1
Special Revenue and Charges [Member]
Operating revenues
Passenger, Mainline	0	0
Passenger, Regional	0	0
Total passenger revenue	0	0
CPA revenues	0	0
Freight and mail	0	0
Other - net revenue	0	0
Total Operating Revenues	0	0
Operating expenses
Operating expenses, excluding fuel	40	0
Economic fuel	10	(2)
Total Operating Expenses	50	(2)
Nonoperating Income (Expense)
Interest income	0	0
Interest expense	0	0
Other	0	0
Nonoperating Income (Expense) Total	0	0
Income before income tax	$ (50)	$ 2