Condensed Consolidated Statement of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 463	$ 339
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation and amortization	277	318
Unrealized/realized (gain) loss on fuel derivative instruments	(7)	27
Deferred income taxes	72	54
Changes in certain assets and liabilities:
Accounts and other receivables	(15)	(35)
Other assets	(178)	(81)
Accounts payable and accrued liabilities	(501)	92
Air traffic liability	866	918
Cash collateral received from derivative counterparties	65	37
Other, net	(40)	(44)
Net cash provided by operating activities	1,002	1,625
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(409)	(414)
Assets constructed for others	(24)	(49)
Purchases of short-term investments	(200)	(563)
Proceeds from sales of short-term and other investments	560	556
Net cash used in investing activities	(73)	(470)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Employee stock plans	9	7
Reimbursement for assets constructed for others	139	49
Payments of long-term debt and capital lease obligations	(82)	(369)
Payments of cash dividends	(148)	(123)
Repayment of construction obligation	(7)	(2)
Repurchase of common stock	(500)	(550)
Other, net	(13)	4
Net cash used in financing activities	(602)	(984)
NET CHANGE IN CASH AND CASH EQUIVALENTS	327	171
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	1,495	1,680
CASH AND CASH EQUIVALENTS AT END OF PERIOD	1,822	1,851
CASH PAYMENTS FOR:
Interest, net of amount capitalized	18	27
Income taxes	4	6
SUPPLEMENTAL DISCLOSURE OF NONCASH TRANSACTIONS
Flight equipment under capital leases	14	39
Assets constructed for others	$ 40	$ 50