Other Financial Information (Goodwill) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Sep. 30, 2019
Goodwill [Line Items]
Goodwill	$ 6,520	$ 6,536
Automation Solutions [Member]
Goodwill [Line Items]
Goodwill	5,404	5,467
Commercial & Residential Solutions [Member]
Goodwill [Line Items]
Goodwill	1,116	1,069
Climate Technologies [Member]
Goodwill [Line Items]
Goodwill	726	668
Tools & Home Products [Member]
Goodwill [Line Items]
Goodwill	$ 390	$ 401

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

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

Name:	us-gaap_Goodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant