CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current Assets
Cash and cash equivalents	$ 95	$ 122
Marketable securities	1,170	1,130
Total cash and marketable securities	1,265	1,252
Receivables - net	188	130
Inventories and supplies - net	61	58
Deferred income taxes	172	148
Fuel hedge contracts	21	26
Prepaid expenses and other current assets	132	123
Total Current Assets	1,839	1,737
Property and Equipment
Aircraft and other flight equipment	4,361	4,248
Other property and equipment	862	855
Deposits for future flight equipment	341	369
Property and Equipment Total	5,564	5,472
Less accumulated depreciation and amortization	1,925	1,863
Total Property and Equipment - Net	3,639	3,609
Fuel Hedge Contracts	23	39
Other Assets	143	120
Total Assets	5,644	5,505
Current Liabilities
Accounts payable	101	65
Accrued wages, vacation and payroll taxes	132	184
Other accrued liabilities	568	557
Air traffic liability	691	534
Current portion of long-term debt	106	161
Total Current Liabilities	1,598	1,501
Long-Term Debt, Net of Current Portion	840	871
Other Liabilities and Credits
Deferred income taxes	492	446
Deferred revenue	441	443
Obligation for pension and postretirement medical benefits	479	489
Other liabilities	332	334
Other Liabilities and Credits Totals	1,744	1,712
Commitments and Contingencies
Shareholders' Equity
Preferred stock, $1 par value Authorized: 5,000,000 shares, none issued or outstanding	0	0
Common stock, $1 par value Authorized: 100,000,000 shares, Issued: 2013 - 70,492,832 shares; 2012 - 70,376,543 shares	70	70
Capital in excess of par value	657	660
Accumulated other comprehensive (loss)	(429)	(436)
Retained earnings	1,164	1,127
Total Shareholders' Equity	1,462	1,421
Total Liabilities and Shareholders' Equity	$ 5,644	$ 5,505