OPERATING SEGMENT INFORMATION, ASSETS (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Total assets	$ 6,829	$ 6,530
Alaska Airlines [Member]
Total assets	8,630	8,127
Horizon [Member]
Total assets	717	717
Parent [Member]
Total assets	4,929	4,734
Intersegment Elimination [Member]
Total assets	$ (7,447)	$ (7,048)