FLEET TRANSITION AND RESTRUCTURING RELATED EXPENSES (DETAILS) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011 positions	Dec. 31, 2010
Restructuring Cost and Reserve [Line Items]
Fleet transition and restructuring related expenses	$ 0	$ 39	$ 13
Horizon positions eliminated in maintenace division (in positions)		100
Horizon Fleet Transition - CRJ-700 [Member]
Restructuring Cost and Reserve [Line Items]
Fleet transition and restructuring related expenses	0	28	10
Horizon Fleet Transition - Q200 [Member]
Restructuring Cost and Reserve [Line Items]
Fleet transition and restructuring related expenses	0	11	0
Horizon Restructuring [Member]
Restructuring Cost and Reserve [Line Items]
Fleet transition and restructuring related expenses	$ 0	$ 0	$ 3