Acquisitions - Schedule of Recognized Identified Assets Acquired and Liabilities Assumed - Knowledge Lens (Details) - USD ($) $ in Millions	Feb. 28, 2023	Aug. 31, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Business Acquisition [Line Items]
Goodwill			$ 3,529.2	$ 3,524.0	$ 3,625.9
Knowledge Lens
Business Acquisition [Line Items]
Accounts receivable	$ 23.8
Inventories	17.7
Property	27.5
Goodwill	111.3
Other intangible assets	54.1
All other assets	21.0
Total assets acquired	255.4
Less: Other liabilities assumed	(12.6)
Less: Deferred income taxes	(56.6)
Net assets acquired	186.2
Total purchase consideration, net of cash acquired	$ 186.2
Plex Systems
Business Acquisition [Line Items]
Accounts receivable		$ 14.8
Goodwill		1,730.0
All other assets		28.3
Total assets acquired		2,304.5
Less: Other liabilities assumed		(33.4)
Net assets acquired		2,205.5
Total purchase consideration, net of cash acquired		$ 2,205.5