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Stock Based Compensation Plans (Details 2) (USD $)
In Millions, except Per Share data, unless otherwise specified |
12 Months Ended | ||
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May 31, 2011
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May 31, 2010
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May 31, 2009
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| Share based compensation stock option plan other information | |||
| Weighted-average grant-date fair value of stock options granted (per share) | $ 4.02 | $ 4.37 | $ 6.52 |
| Total intrinsic value of stock options exercised | $ 1.9 | $ 1.4 | $ 2.6 |
| Total grant date fair value of stock options vested | $ 20.0 | $ 19.0 | $ 25.8 |
| Weighted average assumptions used for valuation | |||
| Risk-free interest rate | 2.20% | 3.00% | 3.20% |
| Dividend yield | 4.20% | 4.50% | 3.60% |
| Volatility factor | 24.00% | 28.00% | 28.00% |
| Expected option life in years | 6.5 | 6.3 | 6.3 |
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- Definition
Schedule of share based payment award stock options other information
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- Definition
Share based compensation arrangement by share based payment award options vested in period fair value.
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- Details
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- 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://www.xbrl.org/2003/role/presentationRef
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- Definition
The period of time a share-based award is expected to be outstanding. A share-based award's expected term shall be determined based on, among other factors, the instrument's contractual term and the effects of employees' expected exercise and post-vesting employment termination behavior. An entity is required to aggregate individual awards into relatively homogeneous groups. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The estimated measure of the percentage amount 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://www.xbrl.org/2003/role/presentationRef
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- Definition
The risk-free interest rate assumption that is used in valuing an option on its own shares. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- 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://www.xbrl.org/2003/role/presentationRef
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