CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Current Assets
Cash and cash equivalents	$ 102	$ 194
Marketable securities	1,466	1,427
Total cash and marketable securities	1,568	1,621
Receivables—net	411	341
Inventories and supplies—net	57	57
Prepaid expenses and other current assets	180	133
Total Current Assets	2,216	2,152
Property and Equipment
Aircraft and other flight equipment	7,788	7,559
Other property and equipment	1,291	1,222
Deposits for future flight equipment	505	494
Property and Equipment Total	9,584	9,275
Less accumulated depreciation and amortization	3,091	2,991
Total Property and Equipment—Net	6,493	6,284
Goodwill	1,943	1,943
Intangible assets	130	133
Other noncurrent assets	273	234
Other Assets	2,346	2,310
Total Assets	11,055	10,746
Current Liabilities
Accounts payable	115	120
Accrued wages, vacation and payroll taxes	345	418
Air traffic liability	1,112	806
Other accrued liabilities	483	400
Deferred revenue, current	667	635
Current portion of long-term debt	314	307
Total Current Liabilities	3,036	2,686
Long-Term Debt, Net of Current Portion	1,998	2,262
Other Liabilities and Credits
Deferred income taxes	437	370
Deferred revenue, noncurrent	1,110	1,090
Obligation for pension and postretirement medical benefits	464	453
Other liabilities	417	425
Other Liabilities and Credits Totals	2,428	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 - 130,436,306 shares; 2017 - 129,903,498 shares, Outstanding: 2018 - 123,203,707 shares; 2017 - 123,060,638 shares	1	1
Capital in excess of par value	198	164
Treasury stock (common), at cost: 2018 - 7,232,599 shares; 2017 - 6,842,860 shares	(544)	(518)
Accumulated other comprehensive loss	(435)	(380)
Retained earnings	4,373	4,193
Total Shareholders' Equity	3,593	3,460
Total Liabilities and Shareholders' Equity	$ 11,055	$ 10,746