Business Segment Information - Sales and Operating Results (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Sales and operating results of reportable segments
Sales	$ 2,275.4	$ 1,808.1	$ 4,256.4	$ 3,665.4
Purchase accounting depreciation and amortization	(26.6)	(26.1)	(52.6)	(52.2)
Corporate and other	(29.2)	(24.6)	(56.5)	(54.0)
Non-operating pension and postretirement benefit cost	(105.4)	(21.3)	(93.0)	(16.9)
Change in fair value of investments	63.0	(140.7)	203.6	(133.1)
Interest expense, net	(34.5)	(29.6)	(67.3)	(58.7)
Income before income taxes	351.4	41.1	819.3	323.6
Operating Segments
Sales and operating results of reportable segments
Segment operating earnings	484.1	283.4	885.1	638.5
Intelligent Devices
Sales and operating results of reportable segments
Sales	1,023.2	808.6	1,959.4	1,708.9
Intelligent Devices | Operating Segments
Sales and operating results of reportable segments
Segment operating earnings	206.9	118.2	416.3	331.2
Software & Control
Sales and operating results of reportable segments
Sales	741.1	534.9	1,314.4	1,048.8
Software & Control | Operating Segments
Sales and operating results of reportable segments
Segment operating earnings	249.3	131.5	416.6	249.1
Lifecycle Services
Sales and operating results of reportable segments
Sales	511.1	464.6	982.6	907.7
Lifecycle Services | Operating Segments
Sales and operating results of reportable segments
Segment operating earnings	$ 27.9	$ 33.7	$ 52.2	$ 58.2