Business Segment Information - Schedule of Reportable Segments (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Segment Reporting Information [Line Items]
Sales	$ 9,058.0	$ 7,760.4	$ 6,997.4
Sales and operating results of reportable segments
Purchase accounting depreciation and amortization, and impairment	(264.4)	(103.9)	(55.1)
Corporate and other	(127.9)	(104.7)	(120.6)
Non-operating pension and postretirement benefit cost	(82.7)	(4.7)	(63.8)
Change in fair value of investments	279.3	(136.9)	397.4
Legal settlement	0.0	0.0	70.0
Interest expense, net	(125.6)	(118.8)	(93.0)
Income before income taxes	1,608.5	1,073.6	1,526.2
Operating Segments
Segment Reporting Information [Line Items]
Sales	9,058.0	7,760.4	6,997.4
Segment operating earnings	1,929.8	1,542.6	1,391.3
Intelligent Devices
Segment Reporting Information [Line Items]
Sales	4,098.2	3,544.6
Intelligent Devices \| Operating Segments
Segment Reporting Information [Line Items]
Sales	4,098.2	3,544.6	3,311.9
Segment operating earnings	828.2	717.6	702.1
Software & Control
Segment Reporting Information [Line Items]
Sales	2,886.0	2,312.9
Software & Control \| Operating Segments
Segment Reporting Information [Line Items]
Sales	2,886.0	2,312.9	1,947.0
Segment operating earnings	953.2	666.7	531.0
Lifecycle Services \| Operating Segments
Segment Reporting Information [Line Items]
Sales	2,073.8	1,902.9	1,738.5
Segment operating earnings	$ 148.4	$ 158.3	$ 158.2

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