CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net Income	$ 99	$ 184
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	90	88
Stock-based compensation and other	13	9
Changes in certain assets and liabilities:
Changes in deferred tax provision	48	(8)
Increase in air traffic liability	369	199
Increase in deferred revenue	1	36
Other—net	(150)	17
Net cash provided by operating activities	470	525
Property and equipment additions:
Aircraft and aircraft purchase deposits	(160)	(91)
Other flight equipment	(20)	(15)
Other property and equipment	(36)	(13)
Total property and equipment additions, including capitalized interest	(216)	(119)
Purchases of marketable securities	(557)	(358)
Sales and maturities of marketable securities	285	140
Other investing activities	0	1
Net cash used in investing activities	(488)	(336)
Cash flows from financing activities:
Long-term debt payments	(101)	(36)
Common stock repurchases	0	(127)
Dividends paid	(37)	(34)
Other financing activities	11	13
Net cash used in financing activities	(127)	(184)
Net increase (decrease) in cash and cash equivalents	(145)	5
Cash and cash equivalents at beginning of year	328	73
Cash and cash equivalents at end of the period	183	78
Cash paid during the period for:
Interest (net of amount capitalized)	26	8
Income taxes paid	$ 2	$ 13