Restructuring Costs (Details) $ in Millions	12 Months Ended
	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($) employees	Sep. 30, 2015 USD ($) employees	Sep. 30, 2014 USD ($) employees
Restructuring Costs [Roll Forward]
Restructuring liability, beginning balance	$ 54	$ 70	$ 17
Restructuring, expense		96	138	$ 39
Restructuring, paid/utilized		112	85
Restructuring liability, ending balance		$ 54	$ 70	$ 17
Total number of facilities exited		19	12	8
Total number of positions eliminated | employees		1,900	3,100	1,600
Process Management [Member]
Restructuring Costs [Roll Forward]
Restructuring, expense		$ 74	$ 89	$ 17
Industrial Automation [Member]
Restructuring Costs [Roll Forward]
Restructuring, expense		6	13	4
Climate Technologies [Member]
Restructuring Costs [Roll Forward]
Restructuring, expense		5	20	14
Commercial & Residential Solutions [Member]
Restructuring Costs [Roll Forward]
Restructuring, expense		2	11	2
Severance And Benefits [Member]
Restructuring Costs [Roll Forward]
Restructuring liability, beginning balance	44	64	16
Restructuring, expense		66	110
Restructuring, paid/utilized		86	62
Restructuring liability, ending balance		44	64	16
Lease And Other Contract Terminations [Member]
Restructuring Costs [Roll Forward]
Restructuring liability, beginning balance	5	1	0
Restructuring, expense		9	2
Restructuring, paid/utilized		5	1
Restructuring liability, ending balance		5	1	0
Asset Write-Downs [Member]
Restructuring Costs [Roll Forward]
Restructuring liability, beginning balance	0	0	0
Restructuring, expense		4	3
Restructuring, paid/utilized		4	3
Restructuring liability, ending balance		0	0	0
Vacant Facility And Other Shutdown Costs [Member]
Restructuring Costs [Roll Forward]
Restructuring liability, beginning balance	3	3	0
Restructuring, expense		7	9
Restructuring, paid/utilized		7	6
Restructuring liability, ending balance		3	3	0
Start-Up And Moving Costs [Member]
Restructuring Costs [Roll Forward]
Restructuring liability, beginning balance	2	2	1
Restructuring, expense		10	14
Restructuring, paid/utilized		10	13
Restructuring liability, ending balance		2	2	1
Scenario, Forecast [Member]
Restructuring Costs [Roll Forward]
Restructuring, expense	$ 50
Corporate, Non-Segment [Member] | Corporate and other [Member]
Restructuring Costs [Roll Forward]
Restructuring, expense		$ 9	$ 5	$ 2