Business Segments (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Net sales	$ 4,162	$ 4,570	$ 8,313	$ 8,717
Earnings	689	675	1,112	1,266
Interest expense	(36)	(48)	(71)	(91)
Operating Segments [Member] \| Automation Solutions [Member]
Segment Reporting Information [Line Items]
Net sales	2,709	3,010	5,561	5,809
Earnings	391	444	701	851
Operating Segments [Member] \| Commercial & Residential Solutions [Member]
Segment Reporting Information [Line Items]
Net sales	1,458	1,561	2,761	2,899
Earnings	306	328	543	565
Operating Segments [Member] \| Climate Technologies [Member]
Segment Reporting Information [Line Items]
Net sales	1,026	1,092	1,899	1,972
Earnings	217	226	368	372
Operating Segments [Member] \| Tools & Home Products [Member]
Segment Reporting Information [Line Items]
Net sales	432	469	862	927
Earnings	89	102	175	193
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Stock compensation	38	(59)	(18)	(52)
Unallocated pension and postretirement costs	12	27	25	54
Interest expense	(36)	(48)	(71)	(91)
Corporate and other [Member]
Segment Reporting Information [Line Items]
Earnings	(22)	(17)	(68)	(61)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	$ (5)	$ (1)	$ (9)	$ 9

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

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