Condensed Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	3 Months Ended
	Aug. 31, 2013	Aug. 31, 2012
Operating Activities:
Net income	$ 489	$ 459
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	639	573
Provision for uncollectible accounts	37	47
Stock-based compensation	45	40
Deferred income taxes and other noncash items	89	122
Changes in assets and liabilities:
Receivables	10	3
Other assets	(31)	147
Accounts payable and other liabilities	(343)	(474)
Other, net	(6)	(14)
Cash provided by operating activities	929	903
Investing Activities:
Capital expenditures	(572)	(972)
Business acquisitions, net of cash acquired		(483)
Proceeds from asset dispositions and other	10	12
Cash used in investing activities	(562)	(1,443)
Financing Activities:
Principal payments on debt		(301)
Proceeds from debt issuance		991
Proceeds from stock issuances	131	30
Excess tax benefit on the exercise of stock options	14	4
Dividends paid	(48)	(44)
Purchase of treasury stock	(278)	(246)
Other, net		(9)
Cash provided by (used in) financing activities	(181)	425
Effect of exchange rate changes on cash	(7)	15
Net increase (decrease) in cash and cash equivalents	179	(100)
Cash and cash equivalents at beginning of period	4,917	2,843
Cash and cash equivalents at end of period	$ 5,096	$ 2,743