COMMITMENTS (DETAILS) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014 carriers	Jun. 30, 2013	Jun. 30, 2014 carriers	Jun. 30, 2013
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Rent Expense	$ 66	$ 83	$ 141	$ 153
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 2014	149		149
2015	423		423
2016	359		359
2017	382		382
2018	430		430
Thereafter	1,037		1,037
Total	2,780		2,780
Capacity Purchase Agreements [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Remainder of 2014	25		25
2015	44		44
2016	32		32
2017	32		32
2018	14		14
Thereafter	0		0
Total	147		147
Engine Maintenance [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Remainder of 2014	5		5
2015	10		10
2016	0		0
2017	0		0
2018	0		0
Thereafter	0		0
Total	15		15
Aircraft Leases [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Operating Leases, Number of Units	59		59
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Remainder of 2014	26		26
2015	103		103
2016	82		82
2017	52		52
2018	36		36
Thereafter	43		43
Total	342		342
Facility Leases [Member]
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
Remainder of 2014	47		47
2015	89		89
2016	86		86
2017	83		83
2018	36		36
Thereafter	211		211
Total	$ 552		$ 552
B737 [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Committed to Purchase (in Aircraft)	66		66
Options to Purchase Additional (in Aircraft)	58		58
B737-900ER [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Committed to Purchase (in Aircraft)	29		29
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]
Options to Purchase Additional (in Aircraft)	7		7
Assets Leased to Others [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Operating Leases, Number of Units	14		14
Non Operating Aircraft [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
Operating Leases, Number of Units	16		16