Business Segments (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information [Line Items]
Net sales	$ 5,005		$ 4,697	$ 14,269	$ 13,289
Earnings	1,195		784	3,181	2,084
Gain from periodic distribution from retained subordinated interest in Vertiv (VRT)	0	$ 453	0	453	0
Gain (loss) on sale of business	483		0	483	0
Interest expense	(50)		(37)	(140)	(115)
Operating Segments [Member] | Automation Solutions [Member]
Segment Reporting Information [Line Items]
Net sales	2,872		2,865	8,451	8,193
Earnings	530		519	1,618	1,354
Operating Segments [Member] | AspenTech
Segment Reporting Information [Line Items]
Net sales	239		82	405	239
Earnings	57		2	51	(1)
Operating Segments [Member] | Commercial & Residential Solutions [Member]
Segment Reporting Information [Line Items]
Net sales	1,902		1,757	5,430	4,878
Earnings	407		375	1,071	1,042
Operating Segments [Member] | Climate Technologies [Member]
Segment Reporting Information [Line Items]
Net sales	1,380		1,268	3,884	3,459
Earnings	300		274	754	731
Operating Segments [Member] | Tools & Home Products [Member]
Segment Reporting Information [Line Items]
Net sales	522		489	1,546	1,419
Earnings	107		101	317	311
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Stock compensation	(16)		(66)	(107)	(191)
Unallocated pension and postretirement costs	25		24	76	71
Gain from periodic distribution from retained subordinated interest in Vertiv (VRT)	0		0	453	0
Gain (loss) on sale of business	483		0	483	0
Interest expense	(50)		(37)	(140)	(115)
Corporate and other [Member]
Segment Reporting Information [Line Items]
Earnings	(241)		(33)	(324)	(76)
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net sales	$ (8)		$ (7)	$ (17)	$ (21)