| Stock-Based Compensation Plans (Other Information Pertaining to Stock Option) (Details) - Stock Options [Member] - USD ($) $ in Millions | 12 Months Ended | ||
|---|---|---|---|
| May 31, 2022 | May 31, 2021 | May 31, 2020 | |
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Total intrinsic value of stock options exercised | $ 44.3 | $ 58.5 | $ 22.0 | 
| Total grant-date fair value of stock options vested | $ 6.4 | $ 6.0 | $ 5.0 | 
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- 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. 
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- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Details 
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