Share-Based Payments (Schedule of Share Option Activity) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Sep. 30, 2025	Sep. 30, 2024
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding as of October 1, 2024	1.1
Granted	0.0
Exercised	0.0
Canceled and Expired	(0.1)
Weighted-average remaining contractual term, outstanding (in years)	4 years 9 months
Outstanding as of September 30, 2025	1.0	1.1
Weighted-average remaining contractual term, vested and unvested expected to vest (in years)	4 years 9 months
Vested and unvested expected to vest as of September 30, 2025	1.0
Exercisable as of September 30, 2025	0.9
Weighted-average exercise price, outstanding (in usd per share)	$ 39.78	$ 42.93
Weighted-average exercise price, granted (in usd per share)	0
Weighted-average exercise price, canceled (in usd per share)	74.10
Weighted-average exercise price, exercised (in usd per share)	0
Weighted-average exercise price, vested and unvested expected to vest (in usd per share)	39.78
Weighted-average exercise price, exercisable (in usd per share)	$ 40.36
Aggregate intrinsic value, outstanding	$ 0.0
Aggregate intrinsic value, unvested expected to vest	$ 0.0

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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- Definition

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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Weighted average price of options that were either forfeited or expired.

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Gross number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

Number of options outstanding, including both vested and non-vested options.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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No definition available.

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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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- Definition

Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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- Definition

Weighted average price at which option holders acquired shares when converting their stock options into shares.

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- Definition

Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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- Definition

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Number of share options (or share units) exercised during the current period.

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