Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2018	Aug. 31, 2017
Operating Activities:
Net income	$ 835	$ 596
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	808	751
Provision for uncollectible accounts	82	60
Stock-based compensation	68	62
Deferred income taxes and other noncash items	23	97
Changes in assets and liabilities:
Receivables	(380)	(271)
Other assets	(120)	(142)
Accounts payable and other liabilities	(584)	(540)
Other, net	(31)	(23)
Cash provided by operating activities	701	590
Investing Activities:
Capital expenditures	(1,179)	(1,044)
Proceeds from asset dispositions and other	78	6
Cash used in investing activities	(1,101)	(1,038)
Financing Activities:
Proceeds from short-term borrowings	299
Principal payments on debt	(2)	(12)
Proceeds from stock issuances	25	150
Dividends paid	(173)	(134)
Purchase of treasury stock	(625)	(86)
Other, net	4	(6)
Cash used in financing activities	(472)	(88)
Effect of exchange rate changes on cash	(24)	70
Net (decrease) increase in cash and cash equivalents	(896)	(466)
Cash and cash equivalents at beginning of period	3,265	3,969
Cash and cash equivalents at end of period	$ 2,369	$ 3,503