CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net Income	$ 197	$ 386
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	191	180
Stock-based compensation and other	17	25
Changes in certain assets and liabilities:
Changes in deferred tax provision	67	127
Increase in air traffic liability	306	384
Increase in deferred revenue	52	69
Other—net	(104)	(87)
Net cash provided by operating activities	726	1,084
Property and equipment additions:
Aircraft and aircraft purchase deposits	(271)	(404)
Other flight equipment	(56)	(45)
Other property and equipment	(96)	(63)
Total property and equipment additions, including capitalized interest	(423)	(512)
Purchases of marketable securities	(529)	(1,010)
Sales and maturities of marketable securities	474	541
Other investing activities	10	10
Net cash used in investing activities	(468)	(971)
Cash flows from financing activities:
Long-term debt payments	(258)	(159)
Common stock repurchases	(25)	(22)
Dividends paid	(79)	(74)
Other financing activities	15	12
Net cash used in financing activities	(347)	(243)
Net increase (decrease) in cash, cash equivalents, and restricted cash	(89)	(130)
Cash, cash equivalents, and restricted cash at beginning of year	197	328
Cash, cash equivalents, and restricted cash at end of the period	108	198
Cash paid during the period for:
Interest (net of amount capitalized)	39	42
Income taxes	$ 0	$ 14