Income Taxes (Cash Paid for Taxes, Net of Refunds) (Details) - USD ($) $ in Millions	6 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Income Tax Disclosure [Abstract]
Income tax payments, net of refunds	$ 263.4	$ 710.1

Amount, after refund, of cash paid to foreign, federal, state, and local jurisdictions as income tax.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 230
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-Name Accounting Standards Codification
-Section 50
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 740
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