COMMITMENTS (DETAILS) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013 carriers	Sep. 30, 2012	Sep. 30, 2013 carriers	Sep. 30, 2012
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Rent Expense	$ 75	$ 69	$ 228	$ 207
Airline, Capacity Purchase Arrangements, Carriers	3		3
Airline, Capacity Purchase Arrangements, Percent	100.00%		100.00%
Aircraft Commitments [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Remainder of 2013	117		117
2014	448		448
2015	328		328
2016	279		279
2017	338		338
Thereafter	1,450		1,450
Total	2,960		2,960
Capacity Purchase Agreements [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Remainder of 2013	9		9
2014	38		38
2015	31		31
2016	18		18
2017	19		19
Thereafter	8		8
Total	123		123
Engine Maintenance [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Remainder of 2013	3		3
2014	10		10
2015	11		11
2016	0		0
2017	0		0
Thereafter	0		0
Total	24		24
Aircraft Leases [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Operating Leases, Number of Units	63		63
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Remainder of 2013	17		17
2014	127		127
2015	105		105
2016	82		82
2017	51		51
Thereafter	79		79
Total	461		461
Facility Leases [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Remainder of 2013	12		12
2014	45		45
2015	35		35
2016	27		27
2017	21		21
Thereafter	148		148
Total	$ 288		$ 288
B737 [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Committed to Purchase (in Aircraft)	72		72
Options to Purchase Additional (in Aircraft)	64		64
B737-900ER [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Committed to Purchase (in Aircraft)	35		35
B737 MAX [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Committed to Purchase (in Aircraft)	37		37
Q400 [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Committed to Purchase (in Aircraft)	3		3
Options to Purchase Additional (in Aircraft)	7		7
Assets Leased to Others [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Operating Leases, Number of Units	11		11
Non Operating Aircraft [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Operating Leases, Number of Units	14		14