DERIVATIVE FINANCIAL INSTRUMENTS EFFECTS ON EARNINGS AND AOCL (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018
Derivative [Line Items]
Non-operating income, net	$ 198	$ 409	$ 681	$ 891
Interest expense	(509)	(533)	(1,557)	(1,477)
Non-Operating Income, Net [Member]
Derivative [Line Items]
Non-operating income, net	198	409	681	891
Effects of derivative instruments designated as hedges on income [Abstract]:
Total gain (loss) on hedges recognized in income	14	51	(25)	142
Interest Expense [Member]
Derivative [Line Items]
Interest expense	(509)	(533)	(1,557)	(1,477)
Effects of derivative instruments designated as hedges on income [Abstract]:
Total gain (loss) on hedges recognized in income	0	0	0	0
Fair value hedges [Member] \| Non-Operating Income, Net [Member] \| Interest Rate Swaps [Member]
Effects of derivative instruments designated as hedges on income [Abstract]:
Derivative instruments	0	0	0	0
Hedged items	0	0	0	0
Fair value hedges [Member] \| Non-Operating Income, Net [Member] \| Cross-Currency Interest Rate Swaps [Member]
Effects of derivative instruments designated as hedges on income [Abstract]:
Derivative instruments	7	0	(21)	0
Hedged items	(4)	0	22	0
Fair value hedges [Member] \| Interest Expense [Member] \| Interest Rate Swaps [Member]
Effects of derivative instruments designated as hedges on income [Abstract]:
Derivative instruments	43	(47)	5	(94)
Hedged items	(43)	47	(5)	94
Fair value hedges [Member] \| Interest Expense [Member] \| Cross-Currency Interest Rate Swaps [Member]
Effects of derivative instruments designated as hedges on income [Abstract]:
Derivative instruments	9	0	10	0
Hedged items	(9)	0	(10)	0
Cash flow hedges [Member] \| Cross-Currency Swaps [Member]
Effects of derivative and non-derivative instruments on other comprehensive income (OCI) or loss (OCL) [Abstract]
Cross-currency swap agreements designated as cash flow hedges	(7)	57	(62)	161
Cash flow hedges [Member] \| Non-Operating Income, Net [Member] \| Cross-Currency Swaps [Member]
Effects of derivative instruments designated as hedges on income [Abstract]:
Amount of gain (loss) reclassified from accumulated OCI or OCL	11	51	(26)	142
Cash flow hedges [Member] \| Interest Expense [Member] \| Cross-Currency Swaps [Member]
Effects of derivative instruments designated as hedges on income [Abstract]:
Amount of gain (loss) reclassified from accumulated OCI or OCL	0	0	0	0
Net Investment Hedge [Member] \| Foreign Currency Borrowings [Member]
Effects of derivative and non-derivative instruments on other comprehensive income (OCI) or loss (OCL) [Abstract]
Foreign currency borrowings designated as net investment hedge	$ 0	$ (31)	$ 0	$ (85)

Nonoperating income expense including elimination of net income loss attributable to noncontrolling interests.

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Summary of derivative and non-derivative instruments impact on other comprehensive income or loss.

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Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

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Amount of the cost of borrowed funds accounted for as interest expense.

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