CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net Income	$ 4	$ 93
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	94	90
Stock-based compensation and other	8	13
Changes in certain assets and liabilities:
Changes in deferred tax provision	2	44
Increase in air traffic liability	316	364
Increase in deferred revenue	26	31
Other—net	(144)	(165)
Net cash provided by operating activities	306	470
Property and equipment additions:
Aircraft and aircraft purchase deposits	(135)	(160)
Other flight equipment	(29)	(20)
Other property and equipment	(71)	(36)
Total property and equipment additions, including capitalized interest	(235)	(216)
Purchases of marketable securities	(238)	(557)
Sales and maturities of marketable securities	301	285
Other investing activities	8	0
Net cash used in investing activities	(164)	(488)
Cash flows from financing activities:
Long-term debt payments	(120)	(101)
Common stock repurchases	(12)	0
Dividends paid	(39)	(37)
Other financing activities	15	11
Net cash used in financing activities	(156)	(127)
Net increase (decrease) in cash, cash equivalents, and restricted cash	(14)	(145)
Cash, cash equivalents, and restricted cash at beginning of year	197	328
Cash, cash equivalents, and restricted cash at end of the period	183	183
Cash paid during the period for:
Interest (net of amount capitalized)	24	26
Income taxes	$ 0	$ 2