Condensed Consolidating Statements of Cash Flows (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Nov. 30, 2017	Nov. 30, 2017	Nov. 30, 2016
Condensed Financial Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES		$ 1,498	$ 2,635
Investing Activities:
Capital expenditures		(2,621)	(2,681)
Business acquisitions, net of cash acquired		(44)
Proceeds from asset dispositions and other		12	100
Cash used in investing activities		(2,653)	(2,581)
Financing Activities:
Proceeds from short-term borrowings		250
Principal payments on debt		(28)	(43)
Proceeds from stock issuances		205	164
Dividends paid		(268)	(213)
Purchase of treasury stock	$ (184)	(270)	(334)
Other, net		3	(5)
Cash used in financing activities		(108)	(431)
Effect of exchange rate changes on cash		62	(98)
Net decrease in cash and cash equivalents		(1,201)	(475)
Cash and cash equivalents at beginning of period		3,969	3,534
Cash and cash equivalents at end of period	2,768	2,768	3,059
Consolidation Eliminations [Member]
Condensed Financial Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES		19	(12)
Financing Activities:
Net decrease in cash and cash equivalents		19	(12)
Cash and cash equivalents at beginning of period		(47)	(43)
Cash and cash equivalents at end of period	(28)	(28)	(55)
Parent Company [Member] | Reportable Legal Entities [Member]
Condensed Financial Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES		(1,959)	(376)
Investing Activities:
Proceeds from asset dispositions and other			84
Cash used in investing activities			84
Financing Activities:
Net transfers from (to) Parent		947	24
Payment on loan between subsidiaries		167	8
Proceeds from short-term borrowings		250
Proceeds from stock issuances		205	164
Dividends paid		(268)	(213)
Purchase of treasury stock		(270)	(334)
Other, net		3	4
Cash used in financing activities		1,034	(347)
Effect of exchange rate changes on cash			(5)
Net decrease in cash and cash equivalents		(925)	(644)
Cash and cash equivalents at beginning of period		1,884	1,974
Cash and cash equivalents at end of period	959	959	1,330
Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Financial Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES		3,504	2,550
Investing Activities:
Capital expenditures		(2,474)	(2,455)
Business acquisitions, net of cash acquired		(44)
Proceeds from asset dispositions and other		12	13
Cash used in investing activities		(2,506)	(2,442)
Financing Activities:
Net transfers from (to) Parent		(1,019)	(94)
Intercompany dividends			1
Payment on loan between subsidiaries			(15)
Principal payments on debt		(18)	(31)
Other, net			(2)
Cash used in financing activities		(1,037)	(141)
Effect of exchange rate changes on cash		56	1
Net decrease in cash and cash equivalents		17	(32)
Cash and cash equivalents at beginning of period		325	326
Cash and cash equivalents at end of period	342	342	294
Non Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Financial Statements Captions [Line Items]
CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES		(66)	473
Investing Activities:
Capital expenditures		(147)	(226)
Proceeds from asset dispositions and other			3
Cash used in investing activities		(147)	(223)
Financing Activities:
Net transfers from (to) Parent		72	70
Intercompany dividends			(1)
Payment on loan between subsidiaries		(167)	7
Principal payments on debt		(10)	(12)
Other, net			(7)
Cash used in financing activities		(105)	57
Effect of exchange rate changes on cash		6	(94)
Net decrease in cash and cash equivalents		(312)	213
Cash and cash equivalents at beginning of period		1,807	1,277
Cash and cash equivalents at end of period	$ 1,495	$ 1,495	$ 1,490