Business Segments Business Segment Information (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]
Depreciation and amortization	$ 211	$ 204	$ 422	$ 406
Corporate and other [Member] | Corporate and Other [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	9	11	18	20
Operating Segments [Member] | Automation Solutions [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	138	131	277	260
Operating Segments [Member] | Commercial & Residential Solutions [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	64	62	127	126
Operating Segments [Member] | Climate Technologies [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	45	45	89	90
Operating Segments [Member] | Tools & Home Products [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization	$ 19	$ 17	$ 38	$ 36