DERIVATIVE FINANCIAL INSTRUMENTS EFFECTS ON EARNINGS AND AOCL (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Nov. 30, 2019	Nov. 30, 2018	Nov. 30, 2019	Nov. 30, 2018
Derivative [Line Items]
Non-operating income, net	$ 92	$ 192	$ 191	$ 484
Interest expense	465	519	959	1,048
Non-Operating Income, Net [Member]
Derivative [Line Items]
Non-operating income, net	92	192	191	484
Effects of derivative instruments designated as hedges on income [Abstract]:
Total gain (loss) on hedges recognized in income	(8)	(52)	(19)	(39)
Interest Expense [Member]
Derivative [Line Items]
Interest expense	465	519	959	1,048
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	5	(24)	(13)	(28)
Hedged items	(3)	21	12	26
Fair value hedges [Member] \| Interest Expense [Member] \| Interest Rate Swaps [Member]
Effects of derivative instruments designated as hedges on income [Abstract]:
Derivative instruments	(4)	(31)	12	(38)
Hedged items	4	31	(12)	38
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	(16)	1	7	1
Hedged items	16	(1)	(7)	(1)
Cash flow hedges [Member] \| Cross-Currency Swap Agreements [Member]
Effects of derivative instruments designated as hedges on income [Abstract]:
Cross-currency swap agreements designated as cash flow hedges	(2)	(41)	(34)	(55)
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	(10)	(49)	(18)	(37)
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

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

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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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Amount, before tax and after reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

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