Retirement Plans - Schedule of Retirement Plan Costs (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Aug. 31, 2021 |
Aug. 31, 2020 |
|
| Pension And Other Postretirement Benefit Expense [Abstract] | ||
| Defined benefit pension plans, net | $ (3) | $ 25 |
| Defined contribution plans | 180 | 159 |
| Postretirement healthcare plans | 22 | 21 |
| Retirement plans costs | $ 199 | $ 205 |