OPERATING SEGMENT INFORMATION (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($) carriers	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) carriers segment	Jun. 30, 2014 USD ($)
Segment Reporting Information [Line Items]
Capacity purchase arrangements (percent)	100.00%		100.00%
Number of operating airlines | carriers	2		2
Number of operating segments | segment			3
Operating revenues
Passenger, Mainline	$ 1,019	$ 974	$ 1,920	$ 1,828
Passenger, Regional	212	200	398	386
Total passenger revenue	1,231	1,174	2,318	2,214
CPA revenues	0	0	0	0
Freight and mail	30	32	53	56
Other - net	176	169	335	327
Total Operating Revenues	1,437	1,375	2,706	2,597
Operating expenses
Operating expenses, excluding fuel	804	752	1,600	1,474
Economic fuel	261	360	496	718
Total Operating Expenses	1,065	1,112	2,096	2,192
Nonoperating Income (Expense)
Interest income	6	5	11	10
Interest expense	(11)	(12)	(22)	(25)
Other	9	9	17	27
Nonoperating Income (Expense)	4	2	6	12
Income (loss) before income tax	376	265	616	417
Air Group Adjusted [Member]
Operating revenues
Passenger, Mainline	1,019	974	1,920	1,828
Passenger, Regional	212	200	398	386
Total passenger revenue	1,231	1,174	2,318	2,214
CPA revenues	0	0	0	0
Freight and mail	30	32	53	56
Other - net	176	169	335	327
Total Operating Revenues	1,437	1,375	2,706	2,597
Operating expenses
Operating expenses, excluding fuel	804	752	1,600	1,474
Economic fuel	267	373	502	739
Total Operating Expenses	1,071	1,125	2,102	2,213
Nonoperating Income (Expense)
Interest income	6	5	11	10
Interest expense	(11)	(12)	(22)	(25)
Other	9	9	17	27
Nonoperating Income (Expense)	4	2	6	12
Income (loss) before income tax	370	252	610	396
Alaska Mainline [Member]
Operating revenues
Passenger, Mainline	1,019	974	1,920	1,828
Passenger, Regional	0	0	0	0
Total passenger revenue	1,019	974	1,920	1,828
CPA revenues	0	0	0	0
Freight and mail	28	31	50	54
Other - net	156	147	298	287
Total Operating Revenues	1,203	1,152	2,268	2,169
Operating expenses
Operating expenses, excluding fuel	645	602	1,284	1,178
Economic fuel	232	324	436	642
Total Operating Expenses	877	926	1,720	1,820
Nonoperating Income (Expense)
Interest income	5	5	10	10
Interest expense	(7)	(9)	(14)	(17)
Other	7	9	14	27
Nonoperating Income (Expense)	5	5	10	20
Income (loss) before income tax	331	231	558	369
Alaska Regional [Member]
Operating revenues
Passenger, Mainline	0	0	0	0
Passenger, Regional	212	200	398	386
Total passenger revenue	212	200	398	386
CPA revenues	0	0	0	0
Freight and mail	2	1	3	2
Other - net	19	20	35	37
Total Operating Revenues	233	221	436	425
Operating expenses
Operating expenses, excluding fuel	169	151	333	302
Economic fuel	35	49	66	97
Total Operating Expenses	204	200	399	399
Nonoperating Income (Expense)
Interest income	0	0	0	0
Interest expense	0	(1)	0	(1)
Other	0	1	0	0
Nonoperating Income (Expense)	0	0	0	(1)
Income (loss) before income tax	29	21	37	25
Horizon [Member]
Operating revenues
Passenger, Mainline	0	0	0	0
Passenger, Regional	0	0	0	0
Total passenger revenue	0	0	0	0
CPA revenues	99	87	198	178
Freight and mail	0	0	0	0
Other - net	1	2	2	3
Total Operating Revenues	100	89	200	181
Operating expenses
Operating expenses, excluding fuel	90	86	181	172
Economic fuel	0	0	0	0
Total Operating Expenses	90	86	181	172
Nonoperating Income (Expense)
Interest income	0	0	0	0
Interest expense	(1)	(2)	(5)	(6)
Other	(1)	(1)	0	0
Nonoperating Income (Expense)	(2)	(3)	(5)	(6)
Income (loss) before income tax	8	0	14	3
Intersegment Elimination [Member]
Operating revenues
Passenger, Mainline	0	0	0	0
Passenger, Regional	0	0	0	0
Total passenger revenue	0	0	0	0
CPA revenues	(99)	(87)	(198)	(178)
Freight and mail	0	0	0	0
Other - net	0	0	0	0
Total Operating Revenues	(99)	(87)	(198)	(178)
Operating expenses
Operating expenses, excluding fuel	(100)	(87)	(198)	(178)
Economic fuel	0	0	0	0
Total Operating Expenses	(100)	(87)	(198)	(178)
Nonoperating Income (Expense)
Interest income	1	0	1	0
Interest expense	(3)	0	(3)	(1)
Other	3	0	3	0
Nonoperating Income (Expense)	1	0	1	(1)
Income (loss) before income tax	2	0	1	(1)
Special Revenue and Charges [Member]
Operating revenues
Passenger, Mainline	0	0	0	0
Passenger, Regional	0	0	0	0
Total passenger revenue	0	0	0	0
CPA revenues	0	0	0	0
Freight and mail	0	0	0	0
Other - net	0	0	0	0
Total Operating Revenues	0	0	0	0
Operating expenses
Operating expenses, excluding fuel	0	0	0	0
Economic fuel	(6)	(13)	(6)	(21)
Total Operating Expenses	(6)	(13)	(6)	(21)
Nonoperating Income (Expense)
Interest income	0	0	0	0
Interest expense	0	0	0	0
Other	0	0	0	0
Nonoperating Income (Expense)	0	0	0	0
Income (loss) before income tax	$ 6	$ 13	$ 6	$ 21