Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Feb. 28, 2021	Feb. 29, 2020
Operating Activities:
Net income	$ 3,363	$ 1,620
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	2,818	2,688
Asset impairment charges		66
Provision for uncollectible accounts	428	295
Stock-based compensation	161	137
Retirement plan mark-to-market adjustment	52
Other noncash items and deferred income taxes	2,020	1,758
Changes in assets and liabilities:
Receivables	(1,187)	(504)
Other assets	(165)	(149)
Accounts payable and other liabilities	63	(2,612)
Other, net	(161)	(21)
Cash provided by operating activities	7,392	3,278
Investing Activities:
Capital expenditures	(4,202)	(4,705)
Business acquisitions, net of cash acquired	(225)
Proceeds from asset dispositions and other	88	15
Cash used in investing activities	(4,339)	(4,690)
Financing Activities:
Proceeds from short-term borrowings, net		298
Principal payments on debt	(105)	(1,045)
Proceeds from debt issuances	970	2,093
Proceeds from stock issuances	482	38
Dividends paid	(513)	(509)
Purchase of treasury stock		(3)
Other, net	(13)	(5)
Cash provided by financing activities	821	867
Effect of exchange rate changes on cash	101	(8)
Net increase (decrease) in cash and cash equivalents	3,975	(553)
Cash and cash equivalents at beginning of period	4,881	2,319
Cash and cash equivalents at end of period	$ 8,856	$ 1,766