Revenue Recognition Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue, Net	$ 5,862	$ 5,341
Products and Systems [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	4,420	3,799
Services [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	1,442	1,542
Building Solutions North America
Disaggregation of Revenue [Line Items]
Revenue, Net	2,152	2,034
Building Solutions North America | Products and Systems [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	1,299	1,242
Building Solutions North America | Services [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	853	792
Building Solutions EMEA/LA
Disaggregation of Revenue [Line Items]
Revenue, Net	959	948
Building Solutions EMEA/LA | Products and Systems [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	544	468
Building Solutions EMEA/LA | Services [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	415	480
Building Solutions Asia Pacific
Disaggregation of Revenue [Line Items]
Revenue, Net	675	604
Building Solutions Asia Pacific | Products and Systems [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	501	334
Building Solutions Asia Pacific | Services [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	174	270
Global Products
Disaggregation of Revenue [Line Items]
Revenue, Net	2,076	1,755
Global Products | Products and Systems [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	2,076	1,755
Global Products | Services [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	0	0
Global Products | Global Products - HVAC [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	1,483	1,218
Global Products | Global Products - Fire & Security [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	544	488
Global Products | Global Products - Industrial Refrigeration [Domain]
Disaggregation of Revenue [Line Items]
Revenue, Net	$ 49	$ 49