CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cash flows from operating activities:
Net Income	$ 4	$ 4
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	106	94
Stock-based compensation and other	11	8
Changes in certain assets and liabilities:
Changes in deferred tax provision	2	2
Increase in air traffic liability	328	316
Increase in deferred revenue	41	26
Other—net	(24)	(144)
Net cash provided by operating activities	468	306
Property and equipment additions:
Aircraft and aircraft purchase deposits	(53)	(135)
Other flight equipment	(29)	(29)
Other property and equipment	(33)	(71)
Total property and equipment additions, including capitalized interest	(115)	(235)
Purchases of marketable securities	(351)	(238)
Sales and maturities of marketable securities	275	301
Other investing activities	5	8
Net cash used in investing activities	(186)	(164)
Cash flows from financing activities:
Proceeds from issuance of debt	254	0
Long-term debt payments	(393)	(120)
Common stock repurchases	(13)	(13)
Dividends paid	(43)	(40)
Other financing activities	24	17
Net cash used in financing activities	(171)	(156)
Net increase (decrease) in cash, cash equivalents, and restricted cash	111	(14)
Cash, cash equivalents, and restricted cash at beginning of year	114	197
Cash, cash equivalents, and restricted cash at end of the period	225	183
Cash paid during the period for:
Interest (net of amount capitalized)	18	24
Income taxes	$ 0	$ 0