CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 177	$ 194
Marketable securities	1,351	1,427
Total cash and marketable securities	1,528	1,621
Receivables—net	350	341
Inventories and supplies—net	62	57
Prepaid expenses and other current assets	174	133
Total Current Assets	2,114	2,152
Property and Equipment
Aircraft and other flight equipment	7,567	7,559
Other property and equipment	1,287	1,222
Deposits for future flight equipment	560	494
Property and Equipment Total	9,414	9,275
Less accumulated depreciation and amortization	3,011	2,991
Total Property and Equipment—Net	6,403	6,284
Goodwill	1,943	1,943
Intangible assets	132	133
Other noncurrent assets	256	234
Other Assets	2,331	2,310
Total Assets	10,848	10,746
Current Liabilities
Accounts payable	102	120
Accrued wages, vacation and payroll taxes	299	418
Air traffic liability	1,122	806
Other accrued liabilities	433	400
Deferred revenue, current	649	635
Current portion of long-term debt	387	307
Total Current Liabilities	2,992	2,686
Long-Term Debt, Net of Current Portion	2,062	2,262
Other Liabilities and Credits
Deferred income taxes	372	370
Deferred revenue, noncurrent	1,102	1,090
Obligation for pension and postretirement medical benefits	458	453
Other liabilities	423	425
Other Liabilities and Credits Totals	2,355	2,338
Commitments and Contingencies
Shareholders' Equity
Preferred stock, $0.01 par value, Authorized: 5,000,000 shares, none issued or outstanding	0	0
Common stock, $0.01 par value, Authorized: 400,000,000 shares, Issued: 2018 - 130,378,645 shares; 2017 - 129,903,498 shares, Outstanding: 2018 - 123,350,124 shares; 2017 - 123,060,638 shares	1	1
Capital in excess of par value	190	164
Treasury stock (common), at cost: 2018 - 7,028,521 shares; 2017 - 6,842,860 shares	(531)	(518)
Accumulated other comprehensive loss	(440)	(380)
Retained earnings	4,219	4,193
Total Shareholders' Equity	3,439	3,460
Total Liabilities and Shareholders' Equity	$ 10,848	$ 10,746