Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Nov. 30, 2018	Nov. 30, 2018	Nov. 30, 2017
Condensed Cash Flow Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) 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	$ (646)	(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	2,123	2,768
Consolidation Eliminations [Member]
Condensed Cash Flow Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES		(47)	19
FINANCING ACTIVITIES
Net (decrease) increase in cash and cash equivalents		(47)	19
Cash and cash equivalents at beginning of period		(15)	(47)
Cash and cash equivalents at end of period	(62)	(62)	(28)
Parent Company [Member] \| Reportable Legal Entities [Member]
Condensed Cash Flow Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES		262	(1,959)
INVESTING ACTIVITIES
Capital expenditures		(2)
Proceeds from asset dispositions and other		(45)
Cash used in investing activities		(47)
FINANCING ACTIVITIES
Proceeds from short-term borrowings		248	250
Net transfers from (to) Parent		(344)	947
Payment on loan between subsidiaries			167
Proceeds from debt issuances		1,233
Principal payments on debt		(750)
Proceeds from stock issuances		45	205
Dividends paid		(173)	(268)
Purchase of treasury stock		(1,271)	(270)
Other, net			3
Cash used in financing activities		(1,012)	1,034
Net (decrease) increase in cash and cash equivalents		(797)	(925)
Cash and cash equivalents at beginning of period		1,485	1,884
Cash and cash equivalents at end of period	688	688	959
Guarantor Subsidiaries [Member[ \| Reportable Legal Entities [Member]
Condensed Cash Flow Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES		1,631	3,504
INVESTING ACTIVITIES
Capital expenditures		(2,337)	(2,474)
Business acquisitions, net of cash acquired			(44)
Proceeds from asset dispositions and other		83	12
Cash used in investing activities		(2,254)	(2,506)
FINANCING ACTIVITIES
Net transfers from (to) Parent		350	(1,019)
Intercompany dividends		113
Principal payments on debt		(29)	(18)
Other, net		128
Cash used in financing activities		562	(1,037)
Effect of exchange rate changes on cash		(9)	56
Net (decrease) increase in cash and cash equivalents		(70)	17
Cash and cash equivalents at beginning of period		257	325
Cash and cash equivalents at end of period	187	187	342
Non Guarantor Subsidiaries [Member] \| Reportable Legal Entities [Member]
Condensed Cash Flow Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES		333	(66)
INVESTING ACTIVITIES
Capital expenditures		(295)	(147)
Proceeds from asset dispositions and other		15
Cash used in investing activities		(280)	(147)
FINANCING ACTIVITIES
Net transfers from (to) Parent		(6)	72
Payment on loan between subsidiaries			(167)
Intercompany dividends		(113)
Principal payments on debt		(6)	(10)
Other, net		(127)
Cash used in financing activities		(252)	(105)
Effect of exchange rate changes on cash		(29)	6
Net (decrease) increase in cash and cash equivalents		(228)	(312)
Cash and cash equivalents at beginning of period		1,538	1,807
Cash and cash equivalents at end of period	$ 1,310	$ 1,310	$ 1,495

The net cash inflow (outflow) from parent as a source of financing.

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amount of cash inflow (outflow) from financing activities, including discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

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Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

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