Goodwill and Other Intangible Assets - Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Goodwill
Beginning balance	$ 3,993.0	$ 3,529.0
Acquisition of businesses		417.0
Translation	7.0	47.0
Ending balance	$ 3,839.0	3,993.0	$ 3,529.0
Goodwill, Impairment Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]	Goodwill and intangible asset impairment
Impairment	$ (161.0)		(158.0)
Gross carrying value of Goodwill	4,158.0
Accumulated impairment losses	(319.0)
Intelligent Devices
Goodwill
Beginning balance	900.0	596.0
Acquisition of businesses		283.0
Translation	4.0	21.0
Ending balance	904.0	900.0	596.0
Impairment	0.0
Gross carrying value of Goodwill	904.0
Accumulated impairment losses	0.0
Software & Control
Goodwill
Beginning balance	2,437.0	2,420.0
Acquisition of businesses		0.0
Translation	3.0	17.0
Ending balance	2,440.0	2,437.0	2,420.0
Impairment	0.0
Gross carrying value of Goodwill	2,440.0
Accumulated impairment losses	0.0
Lifecycle Services
Goodwill
Beginning balance	656.0	513.0
Acquisition of businesses		134.0
Translation	0.0	9.0
Ending balance	495.0	$ 656.0	$ 513.0
Impairment	(161.0)
Gross carrying value of Goodwill	814.0
Accumulated impairment losses	$ (319.0)