Goodwill and Other Intangible Assets - Changes in Carrying amount of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Goodwill
Beginning balance	$ 1,075.5	$ 1,077.7
Acquisition of businesses	14.6	6.8
Translation	(19.0)	(9.0)
Ending balance	1,071.1	1,075.5
Architecture & Software
Goodwill
Beginning balance	422.3	417.2
Acquisition of businesses	14.6	6.8
Translation	(4.6)	(1.7)
Ending balance	432.3	422.3
Control Products & Solutions
Goodwill
Beginning balance	653.2	660.5
Acquisition of businesses	0.0	0.0
Translation	(14.4)	(7.3)
Ending balance	$ 638.8	$ 653.2

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

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Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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