CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net Income	$ 769	$ 437	$ 960
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	423	398	372
Stock-based compensation and other	29	47	55
Changes in certain assets and liabilities:
Changes in deferred tax provision	209	146	45
(Increase) decrease in accounts receivable	43	(25)	(39)
Increase (decrease) in air traffic liability	112	(18)	45
Increase (decrease) in deferred revenue	116	149	191
Changes in pension and other postretirement benefits	68	52	17
Other - net	18	9	(41)
Net cash provided by operating activities	1,722	1,195	1,590
Property and equipment additions:
Aircraft and aircraft purchase deposits	(356)	(686)	(804)
Other flight equipment	(178)	(105)	(96)
Other property and equipment	(162)	(169)	(126)
Total property and equipment additions	(696)	(960)	(1,026)
Purchases of marketable securities	(1,810)	(834)	(1,569)
Sales and maturities of marketable securities	1,674	1,116	1,388
Proceeds from disposition of assets and changes in restricted deposits	41	47	78
Net cash used in investing activities	(791)	(631)	(1,129)
Cash flows from financing activities:
Proceeds from issuance of long-term debt, net of issuance costs	450	339	0
Long-term debt payments	(1,058)	(807)	(397)
Common stock repurchases	(75)	(50)	(75)
Cash dividend paid	(173)	(158)	(148)
Other financing activities	43	29	28
Net cash used in financing activities	(813)	(647)	(592)
Net increase (decrease) in cash, cash equivalents, and restricted cash	118	(83)	(131)
Cash, cash equivalents, and restricted cash at beginning of year	114	197	328
Cash, cash equivalents, and restricted cash at end of year	232	114	197
Cash paid during the year for:
Interest, net of amount capitalized	60	72	84
Income taxes, net of refunds received	31	0	177
Cash and cash equivalents	$ 221	$ 105	$ 194