Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Nov. 30, 2018	Nov. 30, 2017
Operating Activities:
Net income	$ 1,770	$ 1,371
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	1,636	1,507
Provision for uncollectible accounts	160	116
Stock-based compensation	108	103
Deferred income taxes and other noncash items	236	327
Changes in assets and liabilities:
Receivables	(1,343)	(983)
Other assets	(111)	(338)
Accounts payable and other liabilities	(227)	(564)
Other, net	(50)	(41)
Cash provided by operating activities	2,179	1,498
Investing Activities:
Capital expenditures	(2,634)	(2,621)
Business acquisitions, net of cash acquired		(44)
Proceeds from asset dispositions and other	53	12
Cash used in investing activities	(2,581)	(2,653)
Financing Activities:
Proceeds from short-term borrowings	248	250
Proceeds from debt issuances	1,233
Principal payments on debt	(785)	(28)
Proceeds from stock issuances	45	205
Dividends paid	(173)	(268)
Purchase of treasury stock	(1,271)	(270)
Other, net	1	3
Cash used in financing activities	(702)	(108)
Effect of exchange rate changes on cash	(38)	62
Net (decrease) increase in cash and cash equivalents	(1,142)	(1,201)
Cash and cash equivalents at beginning of period	3,265	3,969
Cash and cash equivalents at end of period	$ 2,123	$ 2,768