CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net Income	$ 661	$ 700
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	275	281
Stock-based compensation and other	43	19
Changes in certain assets and liabilities:
Changes in deferred tax provision	217	47
Increase in air traffic liability	254	116
Increase in deferred revenue	46	60
Other—net	(139)	(17)
Net cash provided by operating activities	1,357	1,206
Property and equipment additions:
Aircraft and aircraft purchase deposits	(679)	(408)
Other flight equipment	(70)	(35)
Other property and equipment	(92)	(66)
Total property and equipment additions, including capitalized interest	(841)	(509)
Purchases of marketable securities	(1,408)	(775)
Sales and maturities of marketable securities	1,069	638
Other investing activities	38	5
Net cash used in investing activities	(1,142)	(641)
Cash flows from financing activities:
Proceeds from issuance of debt	0	1,546
Long-term debt payments	(265)	(93)
Common stock repurchases	(50)	(193)
Dividends paid	(111)	(102)
Other financing activities	27	22
Net cash provided (used) by financing activities	(399)	1,180
Net increase (decrease) in cash and cash equivalents	(184)	1,745
Cash and cash equivalents at beginning of year	328	73
Cash and cash equivalents at end of the period	144	1,818
Cash paid during the period for:
Interest (net of amount capitalized)	68	12
Income taxes	$ 129	$ 321