CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Current Assets
Cash and cash equivalents	$ 885	$ 281
Marketable securities	1,393	1,510
Total cash and marketable securities	2,278	1,791
Receivables - net	384	383
Inventories and supplies - net	104	116
Prepaid expenses	177	176
Other Assets, Current	186	239
Total Current Assets	3,129	2,705
Property and Equipment
Aircraft and other flight equipment	10,363	10,425
Other property and equipment	1,839	1,814
Deposits for future flight equipment	431	491
Property and Equipment Total	12,633	12,730
Less accumulated depreciation and amortization	4,439	4,342
Total Property and Equipment - Net	8,194	8,388
Operating Lease, Right-of-Use Asset	1,174	1,195
Goodwill	2,033	2,033
Other noncurrent assets	283	292
Other Assets	3,490	3,520
Total Assets	14,813	14,613
Current Liabilities
Accounts payable	181	207
Accrued wages, vacation and payroll taxes	481	584
Other accrued liabilities	791	800
Operating Lease, Liability, Current	158	158
Current portion of long-term debt	301	353
Total Current Liabilities	4,829	4,459
Long-Term Debt, Net of Current Portion	2,264	2,182
Noncurrent Liabilities
Operating Lease, Liability, Noncurrent	1,098	1,125
Deferred Income Tax Liabilities, Net	649	695
Deferred revenue, noncurrent	1,320	1,382
Obligation for pension and postretirement medical benefits	365	362
Other liabilities	311	295
Other Liabilities and Credits Totals	3,743	3,859
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: 2021 - 133,792,045 shares; 2020 - 133,567,534 shares, Outstanding: 2021 - 124,442,101 shares; 2020 - 124,217,590 shares	1	1
Capital in excess of par value	$ 707	$ 695
Treasury Stock, Common, Shares	13,431,563	12,870,477
Treasury stock (common), at cost: 2020 - 9,349,944 shares; 2020 - 9,349,944 shares	$ (840)	$ (819)
Accumulated other comprehensive loss	(294)	(299)
Retained earnings	4,403	4,535
Total Shareholders' Equity	3,977	4,113
Total Liabilities and Shareholders' Equity	14,813	14,613
Mileage Plan Revenue [Member]
Current Liabilities
Contract with Customer, Liability, Current	1,313	1,221
Contract with Customer, Liability, Current	1,313	1,221
Passenger Revenue [Member]
Current Liabilities
Contract with Customer, Liability, Current	1,604	1,136
Contract with Customer, Liability, Current	$ 1,604	$ 1,136