Goodwill and Other Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021	Jul. 31, 2023
Intangible Assets [Line Items]
Goodwill impairment loss		$ 184,000,000	$ 310,000,000
Goodwill	$ 17,936,000,000	17,936,000,000	17,350,000,000	$ 18,335,000,000
Impairment, Intangible Asset, Finite-Lived, Statement of Income or Comprehensive Income [Extensible Enumeration]	Restructuring Costs and Asset Impairment Charges
Indefinite-lived trademarks	$ 412,000,000	412,000,000
Amortization of intangible assets		439,000,000	427,000,000	435,000,000
Global Products
Intangible Assets [Line Items]
Impairment of intangible assets, finite-lived	18,000,000
Building Solutions Asia Pacific
Intangible Assets [Line Items]
Goodwill impairment loss		0	0
Goodwill	1,179,000,000	1,179,000,000	1,116,000,000	$ 1,237,000,000
Impairment of intangible assets, indefinite-lived	10,000,000
Silent-Aire
Intangible Assets [Line Items]
Goodwill impairment loss		184,000,000	75,000,000
Goodwill	0	0
Reporting Unit with Fair Value Exceeding Carrying Value by 10%
Intangible Assets [Line Items]
Goodwill					$ 455,000,000
Fair value in excess of carrying value percentage					10.00%
Reporting Unit with Fair Value Exceeding Carrying Value by 10% | Measurement Input, Discount Rate
Intangible Assets [Line Items]
Increase (decrease) in measurement input					1.00%
Reporting Unit with Fair Value Exceeding Carrying Value by 10% | Measurement Input, Long-Term Revenue Growth Rate
Intangible Assets [Line Items]
Increase (decrease) in measurement input					1.50%
North America Retail
Intangible Assets [Line Items]
Goodwill impairment loss			235,000,000
Goodwill	$ 0	$ 0	$ 0