Accumulated Other Comprehensive Income - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
May 31, 2019 |
May 31, 2018 |
May 31, 2017 |
|
| Accumulated Other Comprehensive Income Loss [Line Items] | |||
| Beginning balance | $ 19,416 | $ 16,073 | $ 13,784 |
| Translation adjustments | (195) | (74) | (171) |
| Ending balance | 17,757 | 19,416 | 16,073 |
| Foreign Currency Translation Loss [Member] | |||
| Accumulated Other Comprehensive Income Loss [Line Items] | |||
| Beginning balance | (759) | (685) | (514) |
| Translation adjustments | (195) | (74) | (171) |
| Ending balance | (954) | (759) | (685) |
| Retirement Plans Adjustments [Member] | |||
| Accumulated Other Comprehensive Income Loss [Line Items] | |||
| Beginning balance | 181 | 270 | 345 |
| Prior service credit and other arising during period | (4) | 1 | |
| Reclassifications from AOCI | (92) | (85) | (76) |
| Ending balance | 89 | 181 | 270 |
| Accumulated Other Comprehensive Loss | |||
| Accumulated Other Comprehensive Income Loss [Line Items] | |||
| Beginning balance | (578) | (415) | (169) |
| Ending balance | $ (865) | $ (578) | $ (415) |