CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net Income	$ 395	$ 444
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	180	180
Stock-based compensation and other	25	13
Changes in certain assets and liabilities:
Changes in deferred tax provision	132	41
Increase in air traffic liability	406	201
Increase in deferred revenue	15	48
Other—net	(69)	(28)
Net cash provided by operating activities	1,084	899
Property and equipment additions:
Aircraft and aircraft purchase deposits	(404)	(268)
Other flight equipment	(45)	(31)
Other property and equipment	(63)	(41)
Total property and equipment additions, including capitalized interest	(512)	(340)
Purchases of marketable securities	(1,010)	(610)
Sales and maturities of marketable securities	541	357
Other investing activities	10	3
Net cash used in investing activities	(971)	(590)
Cash flows from financing activities:
Long-term debt payments	(159)	(57)
Common stock repurchases	(22)	(193)
Dividends paid	(74)	(68)
Other financing activities	12	17
Net cash used in financing activities	(243)	(301)
Net increase (decrease) in cash and cash equivalents	(130)	8
Cash and cash equivalents at beginning of year	328	73
Cash and cash equivalents at end of the period	198	81
Cash paid during the period for:
Interest (net of amount capitalized)	42	8
Income taxes	$ 14	$ 182