Condensed Consolidating Financial Statements (Details 4) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Nov. 30, 2014	Nov. 30, 2014	Nov. 30, 2013
Condensed Financial Statements Captions [Line Items]
Cash provided by (used in) operating activities		$ 2,151	$ 1,609
Investing Activities:
Capital expenditures		(1,890)	(1,690)
Proceeds from asset dispositions and other		7	19
Cash used in investing activities		(1,883)	(1,671)
Financing Activities:
Principal payments on debt		(1)	(3)
Proceeds from stock issuances		189	380
Excess tax benefit on the exercise of stock options		23	20
Dividends paid		(114)	(95)
Purchase of treasury stock	(156)	(947)	(1,219)
Cash used in financing activities		(850)	(917)
Effect of exchange rate changes on cash		(60)	(3)
Net decrease in cash and cash equivalents		(642)	(982)
Cash and cash equivalents at beginning of period		2,908	4,917
Cash and cash equivalents at end of period	2,266	2,266	3,935
Parent Company Member
Condensed Financial Statements Captions [Line Items]
Cash provided by (used in) operating activities		(458)	(139)
Investing Activities:
Capital expenditures		(1)
Proceeds from asset dispositions and other		(1)
Cash used in investing activities		(2)
Financing Activities:
Net transfers from (to) Parent		601	(31)
Proceeds from stock issuances		189	380
Excess tax benefit on the exercise of stock options		23	20
Dividends paid		(114)	(95)
Purchase of treasury stock		(947)	(1,219)
Cash used in financing activities		(248)	(945)
Net decrease in cash and cash equivalents		(708)	(1,084)
Cash and cash equivalents at beginning of period		1,756	3,892
Cash and cash equivalents at end of period	1,048	1,048	2,808
Guarantor Subsidiaries Member
Condensed Financial Statements Captions [Line Items]
Cash provided by (used in) operating activities		2,335	1,545
Investing Activities:
Capital expenditures		(1,809)	(1,521)
Proceeds from asset dispositions and other		17	19
Cash used in investing activities		(1,792)	(1,502)
Financing Activities:
Net transfers from (to) Parent		(610)	64
Payment on loan between subsidiaries		143	(33)
Intercompany dividends		22	22
Principal payments on debt		(1)	(3)
Other, net		(39)
Cash used in financing activities		(485)	50
Effect of exchange rate changes on cash		(17)	(6)
Net decrease in cash and cash equivalents		41	87
Cash and cash equivalents at beginning of period		441	405
Cash and cash equivalents at end of period	482	482	492
Non Guarantor Subsidiaries Member
Condensed Financial Statements Captions [Line Items]
Cash provided by (used in) operating activities		257	246
Investing Activities:
Capital expenditures		(80)	(169)
Proceeds from asset dispositions and other		(9)
Cash used in investing activities		(89)	(169)
Financing Activities:
Net transfers from (to) Parent		9	(33)
Payment on loan between subsidiaries		(143)	33
Intercompany dividends		(22)	(22)
Other, net		39
Cash used in financing activities		(117)	(22)
Effect of exchange rate changes on cash		(43)	3
Net decrease in cash and cash equivalents		8	58
Cash and cash equivalents at beginning of period		861	717
Cash and cash equivalents at end of period	869	869	775
Consolidation Eliminations Member
Condensed Financial Statements Captions [Line Items]
Cash provided by (used in) operating activities		17	(43)
Financing Activities:
Net decrease in cash and cash equivalents		17	(43)
Cash and cash equivalents at beginning of period		(150)	(97)
Cash and cash equivalents at end of period	$ (133)	$ (133)	$ (140)