Consolidated Balance Sheet (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Current assets [Abstract]
Cash and cash equivalents	$ 1,113	$ 829
Short-term investments	1,857	2,315
Accounts and other receivables	332	299
Inventories of parts and supplies, at cost	469	401
Deferred income taxes	246	263
Prepaid expenses and other current assets	210	238
Total current assets	4,227	4,345
Property and equipment, at cost [Abstract]
Flight equipment	16,367	15,542
Ground property and equipment	2,714	2,423
Deposits on flight equipment purchase contracts	416	456
Property and equipment, at cost	19,497	18,421
Less allowance for depreciation and amortization	6,731	6,294
Property and equipment, net	12,766	12,127
Goodwill	970	970
Other assets	633	626
Total assets	18,596	18,068
Current liabilities [Abstract]
Accounts payable	1,107	1,057
Accrued liabilities	1,102	996
Air traffic liability	2,170	1,836
Current maturities of long-term debt	271	644
Total current liabilities	4,650	4,533
Long-term debt less current maturities	2,883	3,107
Deferred income taxes	2,884	2,566
Deferred gains from sale and leaseback of aircraft	63	75
Other non-current liabilities	1,124	910
Stockholders' equity [Abstract]
Common stock	808	808
Capital in excess of par value	1,210	1,222
Retained earnings	5,768	5,395
Accumulated other comprehensive income (loss)	(119)	(224)
Treasury stock, at cost	(675)	(324)
Total stockholders' equity	6,992	6,877
Total liabilities and stockholders' equity	$ 18,596	$ 18,068