INCOME TAXES (Details) - USD ($) $ in Billions |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Nov. 30, 2020 |
Nov. 30, 2019 |
Nov. 30, 2020 |
Nov. 30, 2019 |
May 31, 2020 |
|
| Income Tax Disclosure [Abstract] | |||||
| Effective income tax rate | 17.80% | 17.70% | 15.70% | 16.00% | |
| Deferred Tax Assets, Net [Abstract] | |||||
| Net deferred tax assets | $ 3.4 | $ 3.4 | $ 3.2 | ||