Acquisitions and Divestitures (Details) - USD ($) $ in Millions	6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Sep. 30, 2022
Business Acquisition [Line Items]
Cash paid for business acquisition	$ 89	$ 124
Goodwill	17,559		$ 17,328
Business divestitures, net of cash divested	0	16
Global Products
Business Acquisition [Line Items]
Goodwill	5,487		5,516
Building Solutions EMEA/LA
Business Acquisition [Line Items]
Goodwill	1,924		1,725
Building Solutions EMEA/LA | Business Divestitures, Not Specific
Business Acquisition [Line Items]
Proceeds from divestiture of businesses		18
Business divestitures, net of cash divested		16
Goodwill, written off related to sale of business unit		5
Building Solutions Asia Pacific
Business Acquisition [Line Items]
Goodwill	1,169		1,116
Building Solutions North America
Business Acquisition [Line Items]
Goodwill	8,979		$ 8,971
Individually Immaterial Acquisitions
Business Acquisition [Line Items]
Purchase price, net of cash acquired	115	160
Cash paid for business acquisition	89	124
Individually Immaterial Acquisitions | Global Products
Business Acquisition [Line Items]
Goodwill	53
Individually Immaterial Acquisitions | Building Solutions EMEA/LA
Business Acquisition [Line Items]
Goodwill	$ 14	29
Individually Immaterial Acquisitions | Building Solutions Asia Pacific
Business Acquisition [Line Items]
Goodwill		45
Individually Immaterial Acquisitions | Building Solutions North America
Business Acquisition [Line Items]
Goodwill		$ 24