Stock-Based Compensation Plans (Other Information Pertaining to Stock Option) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
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May 31, 2018 |
May 31, 2017 |
May 31, 2016 |
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| Stock Options [Member] | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Total intrinsic value of stock options exercised | $ 9.1 | $ 23.8 | $ 14.5 |
| Total grant-date fair value of stock options vested | 4.0 | 4.1 | 4.0 |
| Performance Stock Options [Member] | |||
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||
| Total intrinsic value of stock options exercised | 7.9 | 12.4 | $ 1.0 |
| Total grant-date fair value of stock options vested | $ 4.9 | $ 4.9 | |
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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://www.xbrl.org/2003/role/presentationRef
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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://www.xbrl.org/2003/role/presentationRef
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