Business Segment Information - Sales and Operating Results (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jun. 30, 2025	Dec. 31, 2024	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Sales and operating results of reportable segments
Sales	$ 2,144.0		$ 2,051.0	$ 6,026.0	$ 6,229.0
Purchase accounting depreciation and amortization	(35.0)		(35.0)	(106.0)	(108.0)
Corporate and other	(40.0)		(29.0)	(111.0)	(97.0)
Non-operating pension and postretirement benefit credit	0.0		4.0	0.0	14.0
Change in fair value of investments	0.0		(5.0)	(3.0)	1.0
Restructuring charges	0.0	$ (97.0)	(70.0)	0.0	(70.0)
Interest expense, net	(37.0)		(36.0)	(109.0)	(101.0)
Income before income taxes	342.0		255.0	854.0	825.0
Operating Segments
Sales and operating results of reportable segments
Segment operating earnings	454.0		426.0	1,183.0	1,186.0
Intelligent Devices
Sales and operating results of reportable segments
Sales	968.0		957.0	2,670.0	2,858.0
Intelligent Devices \| Operating Segments
Sales and operating results of reportable segments
Segment operating earnings	182.0		193.0	461.0	504.0
Software & Control
Sales and operating results of reportable segments
Sales	629.0		513.0	1,726.0	1,686.0
Software & Control \| Operating Segments
Sales and operating results of reportable segments
Segment operating earnings	199.0		121.0	503.0	418.0
Lifecycle Services
Sales and operating results of reportable segments
Sales	547.0		581.0	1,630.0	1,685.0
Lifecycle Services \| Operating Segments
Sales and operating results of reportable segments
Segment operating earnings	$ 73.0		$ 112.0	$ 219.0	$ 264.0

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