Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Total	$ 6,094	$ 6,068
Products and systems
Disaggregation of Revenue [Line Items]
Total	4,489	4,556
Services
Disaggregation of Revenue [Line Items]
Total	1,605	1,512
Building Solutions North America
Disaggregation of Revenue [Line Items]
Total	2,487	2,367
Building Solutions North America | Products and systems
Disaggregation of Revenue [Line Items]
Total	1,518	1,451
Building Solutions North America | Services
Disaggregation of Revenue [Line Items]
Total	969	916
Building Solutions EMEA/LA
Disaggregation of Revenue [Line Items]
Total	1,038	975
Building Solutions EMEA/LA | Products and systems
Disaggregation of Revenue [Line Items]
Total	572	552
Building Solutions EMEA/LA | Services
Disaggregation of Revenue [Line Items]
Total	466	423
Building Solutions Asia Pacific
Disaggregation of Revenue [Line Items]
Total	507	646
Building Solutions Asia Pacific | Products and systems
Disaggregation of Revenue [Line Items]
Total	337	473
Building Solutions Asia Pacific | Services
Disaggregation of Revenue [Line Items]
Total	170	173
Global Products
Disaggregation of Revenue [Line Items]
Total	2,062	2,080
Global Products | Products and systems
Disaggregation of Revenue [Line Items]
Total	2,062	2,080
Global Products | HVAC
Disaggregation of Revenue [Line Items]
Total	1,418	1,440
Global Products | Fire & Security
Disaggregation of Revenue [Line Items]
Total	547	570
Global Products | Industrial Refrigeration
Disaggregation of Revenue [Line Items]
Total	97	70
Global Products | Services
Disaggregation of Revenue [Line Items]
Total	$ 0	$ 0