Condensed Consolidated Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 733	$ 743	$ 1,195	$ 1,082
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation and amortization	292	319	569	637
Unrealized/realized (gain) loss on fuel derivative instruments	(4)	(6)	(11)	21
Deferred income taxes	131	68	203	121
Changes in certain assets and liabilities:
Accounts and other receivables	(81)	12	(96)	(23)
Other assets	(35)	(119)	(213)	(200)
Accounts payable and accrued liabilities	420	(335)	(80)	(243)
Air traffic liability	100	2	966	920
Cash collateral received from derivative counterparties	75	99	140	136
Other, net	0	(37)	(41)	(81)
Net cash provided by operating activities	1,631	746	2,632	2,370
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(521)	(551)	(929)	(965)
Assets constructed for others	(17)	(47)	(41)	(97)
Purchases of short-term investments	(730)	(559)	(930)	(1,121)
Proceeds from sales of short-term and other investments	574	573	1,134	1,130
Net cash used in investing activities	(694)	(584)	(766)	(1,053)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Employee stock plans	9	7	17	14
Reimbursement for assets constructed for others	17	47	157	97
Payments of long-term debt and capital lease obligations	(75)	(59)	(157)	(428)
Payments of cash dividends	(93)	(76)	(240)	(199)
Repayment of construction obligation	(7)	(2)	(15)	(5)
Repurchase of common stock	(500)	(400)	(1,000)	(950)
Other, net	4	7	(9)	11
Net cash used in financing activities	(645)	(476)	(1,247)	(1,460)
NET CHANGE IN CASH AND CASH EQUIVALENTS	292	(314)	619	(143)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	1,822	1,851	1,495	1,680
CASH AND CASH EQUIVALENTS AT END OF PERIOD	2,114	1,537	2,114	1,537
CASH PAYMENTS FOR:
Interest, net of amount capitalized	34	18	52	45
Income taxes	170	376	174	382
SUPPLEMENTAL DISCLOSURE OF NONCASH TRANSACTIONS
Flight equipment under capital leases	0	65	14	104
Assets constructed for others	$ 40	$ 38	$ 80	$ 87

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