Business Segments (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Net sales	$ 3,914	$ 4,684	$ 12,227	$ 13,401
Earnings	458	767	1,570	2,033
Interest expense	(45)	(43)	(116)	(134)
Operating Segments [Member] \| Automation Solutions [Member]
Segment Reporting Information [Line Items]
Net sales	2,589	3,025	8,150	8,834
Earnings	311	477	1,012	1,328
Operating Segments [Member] \| Commercial & Residential Solutions [Member]
Segment Reporting Information [Line Items]
Net sales	1,327	1,662	4,088	4,561
Earnings	253	371	796	936
Operating Segments [Member] \| Climate Technologies [Member]
Segment Reporting Information [Line Items]
Net sales	970	1,199	2,869	3,171
Earnings	195	278	563	650
Operating Segments [Member] \| Tools & Home Products [Member]
Segment Reporting Information [Line Items]
Net sales	357	463	1,219	1,390
Earnings	58	93	233	286
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Stock compensation	(51)	(31)	(69)	(83)
Unallocated pension and postretirement costs	12	27	37	81
Interest expense	(45)	(43)	(116)	(134)
Corporate and other [Member]
Segment Reporting Information [Line Items]
Earnings	(22)	(34)	(90)	(95)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	$ (2)	$ (3)	$ (11)	$ 6

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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