CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Current Assets
Cash and cash equivalents	$ 281	$ 338
Marketable securities	1,510	2,079
Total cash and marketable securities	1,791	2,417
Receivables - net	383	296
Inventories and supplies - net	116	104
Prepaid Expense	176	163
Other Assets, Current	239	60
Total Current Assets	2,705	3,040
Property and Equipment
Aircraft and other flight equipment	10,425	9,053
Other property and equipment	1,814	1,661
Deposits for future flight equipment	491	670
Property and Equipment	12,730	11,384
Less accumulated depreciation and amortization	4,342	4,127
Total Property and Equipment - Net	8,388	7,257
Other Assets
Operating Lease, Right-of-Use Asset	1,195	1,471
Goodwill and intangible assets	2,033	2,038
Other noncurrent assets	292	380
Total Other Assets	3,520	3,889
Total Assets	14,613	14,186
Current Liabilities
Accounts payable	207	221
Accrued wages, vacation and payroll taxes	584	619
Other accrued liabilities	800	846
Operating Lease, Liability, Current	158	228
Current portion of long-term debt	353	276
Total Current Liabilities	4,459	4,493
Long-Term Debt, Net of Current Portion	2,182	1,883
Other Liabilities and Credits
Operating Lease, Liability, Noncurrent	1,125	1,393
Deferred Income Tax Liabilities, Net	695	574
Deferred revenue	1,382	1,374
Obligation for pension and postretirement medical benefits	362	348
Other liabilities	295	305
Total Other Liabilities and Credits	3,859	3,994
Commitments and Contingencies
Preferred stock, par value	$ 0.01
Preferred stock, shares authorized	5,000,000
Shareholders' Equity
Preferred stock, $0.01 par value, Authorized: 5,000,000 shares, none issued or outstanding	$ 0	$ 0
Common stock, shares, outstanding	126,090,353	127,533,916
Common stock, shares issued	138,960,830	136,883,042
Common stock, $0.01 par value, Authorized: 400,000,000 shares, Issued: 2023 - 138,960,830 shares; 2022 - 136,883,042 shares, Outstanding: 2023 - 126,090,353 shares; 2022 - 127,533,916 shares	$ 1	$ 1
Capital in excess of par value	$ 695	$ 577
Treasury Stock, Common, Shares	9,349,944	12,870,477
Treasury stock (common), at cost: 2023 - 12,870,477 shares; 2022 - 9,349,944 shares	$ (819)	$ (674)
Accumulated other comprehensive loss	(299)	(388)
Retained earnings	4,535	4,300
Shareholders' Equity Total	4,113	3,816
Total Liabilities and Shareholders' Equity	$ 14,613	14,186
Common stock, shares authorized	400,000,000
Common stock, par value	$ 0.01
Air Traffic Liability
Current Liabilities
Air traffic liability	$ 1,136	1,180
Mileage Plan Revenue [Member]
Current Liabilities
Air traffic liability	$ 1,221	$ 1,123