Condensed Consolidated Balance Sheet (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Current assets [Abstract]
Cash and Cash Equivalents, at Carrying Value	$ 1,016	$ 1,261
Short-term Investments	2,640	2,277
Accounts and other receivables	369	195
Inventories of parts and supplies, at cost	459	243
Deferred income taxes	0	214
Prepaid expenses and other current assets	110	89
Total current assets	4,594	4,279
Property and equipment, at cost [Abstract]
Flight equipment	15,451	13,991
Ground property and equipment	2,303	2,122
Deposits on flight equipment purchase contracts	229	230
Property and equipment, at cost	17,983	16,343
Less allowance for depreciation and amortization	6,149	5,765
Property and equipment, net	11,834	10,578
Goodwill	970	0
Other assets	487	606
Total assets	17,885	15,463
Current liabilities [Abstract]
Accounts payable	1,083	739
Accrued liabilities	1,193	863
Air traffic liability	2,058	1,198
Less current maturities	986	505
Total current liabilities	5,320	3,305
Long-term debt less current maturities	3,220	2,875
Deferred income taxes	1,856	2,493
Deferred gains from sale and leaseback of aircraft	78	88
Other non-current liabilities	926	465
Stockholders' equity [Abstract]
Common stock	808	808
Capital in excess of par value	1,222	1,183
Retained earnings	5,251	5,399
Accumulated other comprehensive income (loss)	(513)	(262)
Treasury stock, at cost	(283)	(891)
Total stockholders' equity	6,485	6,237
Total liabilities and stockholders' equity	$ 17,885	$ 15,463