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Share-based Payments - Estimate Fair Value of Stock Options (Details) - Stock options - Stock Incentive Plan - $ / shares	12 Months Ended
	Aug. 31, 2021	Aug. 31, 2020	Aug. 31, 2019
Market Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.50%	0.40%
Expected volatility	36.50%	33.70%
Risk-free interest rate	0.70%	1.50%
Expected life of options	8 years	7 years
Weighted-average fair value of options (in dollars per share)	$ 40.45	$ 44.74
Service Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield		0.40%	0.40%
Expected volatility		33.70%	32.80%
Risk-free interest rate		1.30%	3.00%
Expected life of options		5 years	4 years
Weighted-average fair value of options (in dollars per share)		$ 34.22	$ 34.06

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.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(iii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- 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.

+ References

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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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.

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No definition available.

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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.

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-Publisher FASB
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- 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.

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