RISK MANAGEMENT AND DERIVATIVES - Additional Information (Details) - USD ($)	12 Months Ended
	May 31, 2024	May 31, 2023
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Deferred net gains (net of tax) expected to be reclassified to Net Income during the next 12 months	$ 231,000,000
Maximum term over which the company hedges exposures to the variability of cash flows for its forecasted transactions (in months)	24 months
Interest rate swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total notional amount of outstanding derivatives	$ 1,800,000,000
Derivatives not designated as hedging instruments | Not designated as derivative instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total notional amount of outstanding derivatives	$ 4,400,000,000	$ 4,700,000,000
Derivatives designated as cash flow hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Additional period for forecasted transaction expected to occur	2 months
Percentage of anticipated exposures hedged (percent)	100.00%
Derivatives designated as cash flow hedges | Derivatives designated as hedging instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total notional amount of outstanding derivatives	$ 16,200,000,000	18,200,000,000
Derivatives designated as fair value hedges | Derivatives designated as hedging instruments
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total notional amount of outstanding derivatives	1,800,000,000	0
Derivatives designated as net investment hedges | Foreign exchange forwards and options
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative assets (liabilities), at fair value, net	0	$ 0
Minimum
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Credit risk related contingent features collateral threshold	$ 50,000,000
Minimum | Derivatives designated as cash flow hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Typical time period that anticipated exposures are hedged against (in months)	12 months
Maximum | Derivatives designated as cash flow hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Typical time period that anticipated exposures are hedged against (in months)	24 months