Condensed Consolidated Balance Sheet (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 1,338	$ 1,113
Short-term investments	1,797	1,857
Accounts and other receivables	429	332
Inventories of parts and supplies, at cost	480	469
Deferred income taxes	255	246
Prepaid expenses and other current assets	215	210
Total current assets	4,514	4,227
Property and equipment, at cost:
Flight equipment	16,643	16,367
Ground property and equipment	2,754	2,714
Deposits on flight equipment purchase contracts	594	416
Property and equipment, at cost	19,991	19,497
Less allowance for depreciation and amortization	6,861	6,731
Property and equipment, net	13,130	12,766
Goodwill	970	970
Other assets	583	633
Total assets	19,197	18,596
Current liabilities:
Accounts payable	1,250	1,107
Accrued liabilities	1,004	1,102
Air traffic liability	2,877	2,170
Current maturities of long-term debt	280	271
Total current liabilities	5,411	4,650
Long-term debt less current maturities	2,708	2,883
Deferred income taxes	2,904	2,884
Deferred gains from sale and leaseback of aircraft	60	63
Other noncurrent liabilities	1,153	1,124
Stockholders' equity:
Common stock	808	808
Capital in excess of par value	1,214	1,210
Retained earnings	5,818	5,768
Accumulated other comprehensive loss	(111)	(119)
Treasury stock, at cost	(768)	(675)
Total stockholders' equity	6,961	6,992
Total liabilities and stockholders' equity	$ 19,197	$ 18,596