Condensed Consolidated Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 746	$ 820	$ 1,097	$ 1,333
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation and amortization	319	299	637	588
Loss on asset impairment	0	21	0	21
Unrealized/realized (gain) loss on fuel derivative instruments	(6)	(122)	21	(34)
Deferred income taxes	69	54	131	80
Changes in certain assets and liabilities:
Accounts and other receivables	12	(14)	(23)	(35)
Other assets	(119)	(49)	(200)	(45)
Accounts payable and accrued liabilities	(338)	(288)	(245)	25
Air traffic liability	1	79	897	764
Cash collateral received from (provided to) derivative counterparties	99	347	136	116
Other, net	(37)	(35)	(81)	(85)
Net cash provided by operating activities	746	1,112	2,370	2,728
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(551)	(462)	(965)	(900)
Assets constructed for others	(47)	(26)	(97)	(37)
Purchases of short-term investments	(559)	(773)	(1,121)	(1,029)
Proceeds from sales of short-term and other investments	573	591	1,130	1,122
Payments for (Proceeds from) Other Investing Activities	0	(4)	0	(5)
Net cash used in investing activities	(584)	(674)	(1,053)	(849)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Employee stock plans	7	6	14	17
Reimbursement for assets constructed for others	47	25	97	35
Payments of long-term debt and capital lease obligations	(59)	(48)	(428)	(103)
Payments of cash dividends	(76)	(63)	(199)	(160)
Repayment of construction obligation	(2)	(2)	(5)	(4)
Repurchase of common stock	(400)	(700)	(950)	(1,200)
Other, net	7	(4)	11	(7)
Net cash used in financing activities	(476)	(786)	(1,460)	(1,422)
NET CHANGE IN CASH AND CASH EQUIVALENTS	(314)	(348)	(143)	457
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	1,851	2,388	1,680	1,583
CASH AND CASH EQUIVALENTS AT END OF PERIOD	1,537	2,040	1,537	2,040
CASH PAYMENTS FOR:
Interest, net of amount capitalized	18	23	45	50
Income taxes	376	565	382	638
SUPPLEMENTAL DISCLOSURE OF NONCASH TRANSACTIONS
Flight equipment under capital leases	65	83	104	251
Assets constructed for others	$ 38	$ 55	$ 87	$ 115