OPERATING SEGMENT INFORMATION, ASSETS (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Total assets	$ 6,480	$ 6,181
Alaska Airlines [Member]
Total assets	7,567	6,772
Horizon [Member]
Total assets	781	818
Parent [Member]
Total assets	3,877	3,552
Intersegment Elimination [Member]
Total assets	$ (5,745)	$ (4,961)