Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
May 31, 2020 |
May 31, 2019 |
May 31, 2018 |
|
| Reconciliation Of Unrecognized Tax Benefits Excluding Amounts Pertaining To Examined Tax Returns Roll Forward | |||
| Balance at beginning of year | $ 164 | $ 161 | $ 67 |
| Increases for tax positions taken in the current year | 3 | 3 | |
| Increases for tax positions taken in prior years | 4 | 31 | 103 |
| Decreases for tax positions taken in prior years | (10) | (4) | (10) |
| Settlements | (31) | (21) | (2) |
| Changes due to currency translation | (1) | (3) | |
| Balance at end of year | $ 129 | $ 164 | $ 161 |