COMPREHENSIVE INCOME (LOSS) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Comprehensive income (loss) [Abstract]
Net Income	$ 152	$ (140)	$ 161	$ 5	$ 131	$ 205	$ 112	$ 11	$ 178	$ 459	$ 99
Unrealized gain (loss) on fuel derivative instruments, net of deferred taxes									67	330	366
Unrealized gain (loss) on interest rate swaps, net of deferred taxes									(32)	(15)	27
Other, net of deferred taxes									3	1	13
Total Other comprehensive income									38	316	406
Total comprehensive income									216	775	505
Deferred taxes on unrealized gain (loss) on fuel derivative instruments									42	205	226
Deferred taxes on unrealized gain (loss) on interest rate derivative instruments									20	9	17
Deferred taxes on Other									1	1	8
Accumulated Other Comprehensive Income Loss Net of Tax [Line Items]
Beginning Balance				(262)					(262)
Ending Balance	(224)				(262)				(224)	(262)
Fuel hedge derivatives [Member]
Accumulated Other Comprehensive Income Loss Net of Tax [Line Items]
Beginning Balance				(250)				(580)	(250)	(580)
Changes in fair value									(44)	47
Reclassification to earnings									111	283
Ending Balance	(183)				(250)				(183)	(250)
Interest Rate Swap [Member]
Accumulated Other Comprehensive Income Loss Net of Tax [Line Items]
Beginning Balance				(34)				(19)	(34)	(19)
Changes in fair value									(32)	(15)
Reclassification to earnings									0	0
Ending Balance	(66)				(34)				(66)	(34)
Other [Member]
Accumulated Other Comprehensive Income Loss Net of Tax [Line Items]
Beginning Balance				22				21	22	21
Changes in fair value									3	1
Reclassification to earnings									0	0
Ending Balance	25				22				25	22
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss Net of Tax [Line Items]
Beginning Balance				(262)				(578)	(262)	(578)
Changes in fair value									(73)	33
Reclassification to earnings									111	283
Ending Balance	$ (224)				$ (262)				$ (224)	$ (262)