OPERATING SEGMENT INFORMATION, ASSETS (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Total assets	$ 6,564	$ 6,181
Alaska Airlines [Member]
Total assets	7,922	6,772
Horizon [Member]
Total assets	763	818
Parent [Member]
Total assets	4,161	3,552
Intersegment Elimination [Member]
Total assets	$ (6,282)	$ (4,961)