Share-Based Compensation (Compensation Cost Recognized in Income Statement) (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Share-Based Payment Arrangement [Abstract]
Before-tax share-based compensation cost	$ 49.5	$ 44.5	$ 55.8
Income tax benefit	(12.1)	(11.0)	(13.0)
After-tax share-based compensation cost	$ 37.4	$ 33.5	$ 42.8

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI https://asc.fasb.org/extlink&oid=128089324&loc=d3e5070-113901

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Amount, after tax, of expense for award under share-based payment arrangement.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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