LEASES (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 CapitalLeases	Dec. 31, 2010 CapitalLeases	Dec. 31, 2009
Capital leases, aircraft included in property and equipment [Abstract]
Flight equipment	$ 177	$ 132
Less accumulated depreciation	132	125
Net	45	7
Capital Leased Assets, Number of Units	7	5
Sale Leaseback Transaction [LineItems]
Proceeds from sale leaseback transactions	0	0	381
Deferred gain from sale leaseback transactions	75	88
Terms for all sale leaseback transactions	Under the terms of the lease agreements, the Company will continue to operate and maintain the aircraft. Payments under the lease agreements will be reset every six months based on changes in the six-month LIBO rate.
Frequency That Payments Under Sale Leaseback Agreements Are Reset	every six months
Rental expense for operating leases [Abstract]
Rental expense for operating leases	847	631	596
Number of aircraft under operating leases	192
Future minimum lease payments under capital leases [Abstract]
2012	6
2013	6
2014	6
2015	6
2016	6
Thereafter	26
Total minimum lease payments	56
Less amount representing interest	14
Present value of minimum lease payments	42
Less current portion	3
Long-term portion	39
Future minimum lease payments under noncancelable operating leases [Abstract]
2012	640
2013	717
2014	642
2015	579
2016	489
Thereafter	2,516
Total minimum lease payments	5,583
Capital And Operating Lease Renewal Term	one to five years
2009 Sale and Leaseback of 11 737-700 Aircraft [Member]
Sale Leaseback Transaction [LineItems]
Number of aircraft sold in sale and leaseback transaction (in units)			11
Proceeds from sale leaseback transactions			381
Deferred gain from sale leaseback transactions			$ 9
Minimum Leaseback Period			12
Maximum Leaseback Period			16