Reportable Segments and Geographic Information - Schedule of Geographic Information (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Geographic Information
Total	$ 5,155.8	$ 4,558.9	$ 4,624.3
Americas
Geographic Information
Total	3,779.2	3,315.3	3,478.5
Europe, Middle East, India, Africa
Geographic Information
Total	1,025.5	872.9	803.5
Asia-Australia-Pacific
Geographic Information
Total	$ 351.1	$ 370.7	$ 342.3

Long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 41
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-41

Name:	us-gaap_NoncurrentAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant