OPERATING SEGMENT INFORMATION (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($) carriers	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) carriers segment	Sep. 30, 2014 USD ($)
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	$ 1,057	$ 1,030	$ 2,977	$ 2,858
Passenger, Regional	240	219	638	605
Total passenger revenue	1,297	1,249	3,615	3,463
CPA revenues	0	0	0	0
Freight and mail	30	32	83	88
Other - net	188	184	523	511
Total Operating Revenues	1,515	1,465	4,221	4,062
Operating expenses
Operating expenses, excluding fuel	837	755	2,437	2,230
Economic fuel	245	394	741	1,112
Total Operating Expenses	1,082	1,149	3,178	3,342
Nonoperating Income (Expense)
Interest income	5	5	16	15
Interest expense	(10)	(12)	(32)	(36)
Other	9	7	26	34
Nonoperating Income (Expense)	4	0	10	13
Income (loss) before income tax	437	316	1,053	733
Air Group Adjusted [Member]
Operating revenues
Passenger, Mainline	1,057	1,030	2,977	2,858
Passenger, Regional	240	219	638	605
Total passenger revenue	1,297	1,249	3,615	3,463
CPA revenues	0	0	0	0
Freight and mail	30	32	83	88
Other - net	188	184	523	511
Total Operating Revenues	1,515	1,465	4,221	4,062
Operating expenses
Operating expenses, excluding fuel	837	755	2,437	2,230
Economic fuel	240	390	742	1,129
Total Operating Expenses	1,077	1,145	3,179	3,359
Nonoperating Income (Expense)
Interest income	5	5	16	15
Interest expense	(10)	(12)	(32)	(36)
Other	9	7	26	34
Nonoperating Income (Expense)	4	0	10	13
Income (loss) before income tax	442	320	1,052	716
Alaska Mainline [Member]
Operating revenues
Passenger, Mainline	1,057	1,030	2,977	2,858
Passenger, Regional	0	0	0	0
Total passenger revenue	1,057	1,030	2,977	2,858
CPA revenues	0	0	0	0
Freight and mail	29	30	79	84
Other - net	167	161	465	448
Total Operating Revenues	1,253	1,221	3,521	3,390
Operating expenses
Operating expenses, excluding fuel	667	605	1,951	1,783
Economic fuel	205	338	641	980
Total Operating Expenses	872	943	2,592	2,763
Nonoperating Income (Expense)
Interest income	5	5	15	15
Interest expense	(7)	(8)	(21)	(25)
Other	7	7	21	34
Nonoperating Income (Expense)	5	4	15	24
Income (loss) before income tax	386	282	944	651
Alaska Regional [Member]
Operating revenues
Passenger, Mainline	0	0	0	0
Passenger, Regional	240	219	638	605
Total passenger revenue	240	219	638	605
CPA revenues	0	0	0	0
Freight and mail	1	2	4	4
Other - net	20	22	55	59
Total Operating Revenues	261	243	697	668
Operating expenses
Operating expenses, excluding fuel	181	162	514	464
Economic fuel	35	52	101	149
Total Operating Expenses	216	214	615	613
Nonoperating Income (Expense)
Interest income	0	0	0	0
Interest expense	0	0	0	(1)
Other	0	0	0	0
Nonoperating Income (Expense)	0	0	0	(1)
Income (loss) before income tax	45	29	82	54
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	105	99	303	277
Freight and mail	0	0	0	0
Other - net	1	1	3	4
Total Operating Revenues	106	100	306	281
Operating expenses
Operating expenses, excluding fuel	93	85	274	257
Economic fuel	0	0	0	0
Total Operating Expenses	93	85	274	257
Nonoperating Income (Expense)
Interest income	0	0	0	0
Interest expense	(3)	(4)	(8)	(10)
Other	0	0	0	0
Nonoperating Income (Expense)	(3)	(4)	(8)	(10)
Income (loss) before income tax	10	11	24	14
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	(105)	(99)	(303)	(277)
Freight and mail	0	0	$ 0	0
Other - net	0	0		0
Total Operating Revenues	(105)	(99)	$ (303)	(277)
Operating expenses
Operating expenses, excluding fuel	(104)	(97)	(302)	(274)
Economic fuel	0	0	0	0
Total Operating Expenses	(104)	(97)	(302)	(274)
Nonoperating Income (Expense)
Interest income	0	0	1	0
Interest expense	0	0	(3)	0
Other	2	0	5	0
Nonoperating Income (Expense)	2	0	3	0
Income (loss) before income tax	1	(2)	2	(3)
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
Total Operating Revenues	$ 0	0	0	0
Operating expenses
Operating expenses, excluding fuel	0	0	0	0
Economic fuel	5	4	(1)	(17)
Total Operating Expenses	5	4	(1)	(17)
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	$ (5)	$ (4)	$ 1	$ 17