Stock-Based Compensation Plans (Weighted-Average Assumptions) (Details) - $ / shares |
12 Months Ended | ||
|---|---|---|---|
May 31, 2020 |
May 31, 2019 |
May 31, 2018 |
|
| Stock Options [Member] | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Risk-free interest rate | 2.00% | 2.90% | 2.10% |
| Dividend yield | 3.30% | 3.50% | 3.40% |
| Volatility factor | 0.18% | 0.18% | 0.17% |
| Expected option life in years | 6 years 2 months 12 days | 6 years 1 month 6 days | 6 years 1 month 6 days |
| Weighted-average grant-date fair value of stock options granted (per share) | $ 9.86 | $ 8.87 | $ 6.47 |
| Performance Stock Options [Member] | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Risk-free interest rate | 2.90% | 2.40% | |
| Dividend yield | 3.50% | 3.30% | |
| Volatility factor | 0.18% | 0.18% | |
| Expected option life in years | 6 years 6 months | 6 years 6 months | |
| Weighted-average grant-date fair value of stock options granted (per share) | $ 9.02 | $ 7.45 | |
| X | ||||||||||
- Definition The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
|
| X | ||||||||||
- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Definition Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|