Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2016	Aug. 31, 2015
Operating Activities:
Net income	$ 715	$ 692
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	739	648
Provision for uncollectible accounts	39	28
Stock-based compensation	57	53
Deferred income taxes and other noncash items	173	20
Changes in assets and liabilities:
Receivables	20	50
Other assets	(4)	(89)
Accounts payable and other liabilities	(753)	(151)
Other, net	(15)	(10)
Cash provided by operating activities	971	1,241
Investing Activities:
Capital expenditures	(1,215)	(1,209)
Proceeds from asset dispositions and other	9	10
Cash used in investing activities	(1,206)	(1,199)
Financing Activities:
Principal payments on debt	(12)	(15)
Proceeds from stock issuances	40	46
Excess tax benefit on the exercise of stock options	2	6
Dividends paid	(106)	(71)
Purchases of treasury stock	(222)	(190)
Other, net	(15)
Cash used in financing activities	(313)	(224)
Effect of exchange rate changes on cash	3	(38)
Net decrease in cash and cash equivalents	(545)	(220)
Cash and cash equivalents at beginning of period	3,534	3,763
Cash and cash equivalents at end of period	$ 2,989	$ 3,543