CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current Assets
Cash and cash equivalents	$ 48.2	$ 102.2
Marketable securities	1,093.0	1,038.7
Total cash and marketable securities	1,141.2	1,140.9
Receivables - net	168.3	136.4
Inventories and supplies - net	45.3	44.3
Deferred income taxes	142.5	134.2
Fuel hedge contracts	58.7	46.7
Prepaid expenses and other current assets	100.9	93.0
Total Current Assets	1,656.9	1,595.5
Property and Equipment
Aircraft and other flight equipment	4,113.5	4,041.8
Other property and equipment	851.4	762.3
Deposits for future flight equipment	266.0	262.5
Property and Equipment Total	5,230.9	5,066.6
Less accumulated depreciation and amortization	1,727.2	1,665.1
Total Property and Equipment - Net	3,503.7	3,401.5
Fuel Hedge Contracts	72.8	70.2
Other Assets	148.6	127.8
Total Assets	5,382.0	5,195.0
Current Liabilities
Accounts payable	129.0	103.6
Accrued aircraft rent	4.8	31.6
Accrued wages, vacation and payroll taxes	123.8	163.8
Other accrued liabilities	551.5	513.3
Air traffic liability	654.0	489.4
Current portion of long-term debt	210.1	207.9
Total Current Liabilities	1,673.2	1,509.6
Long-Term Debt, Net of Current Portion	1,036.9	1,099.0
Other Liabilities and Credits
Deferred income taxes	405.2	362.9
Deferred revenue	406.2	410.2
Obligation for pension and postretirement medical benefits	458.4	463.4
Other liabilities	184.1	176.7
Other Liabilities and Credits Totals	1,453.9	1,413.2
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: 2012 - 71,195,578 shares; 2011 - 75,733,044 shares	71.2	37.9
Capital in excess of par value	677.8	840.0
Treasury stock (common), at cost: 2012 - 0 shares; 2011 - 4,783,494 shares	0	(125.3)
Accumulated other comprehensive loss	(382.4)	(390.0)
Retained earnings	851.4	810.6
Shareholders' Equity Total	1,218.0	1,173.2
Total Liabilities and Shareholders' Equity	$ 5,382.0	$ 5,195.0