Restructuring (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring Reserve [Roll Forward]
Beginning restructuring liability			$ 52
Restructuring expense	$ 20	$ 14	40	$ 38
Restructuring utilized/paid			53
Ending restructuring liability	39		39
Severance and benefits [Member]
Restructuring Reserve [Roll Forward]
Beginning restructuring liability			46
Restructuring expense			25
Restructuring utilized/paid			35
Ending restructuring liability	36		36
Lease and other contract terminations [Member]
Restructuring Reserve [Roll Forward]
Beginning restructuring liability			3
Restructuring expense			0
Restructuring utilized/paid			1
Ending restructuring liability	2		2
Assets Write Downs [Member]
Restructuring Reserve [Roll Forward]
Beginning restructuring liability			0
Restructuring expense			2
Restructuring utilized/paid			2
Ending restructuring liability	0		0
Vacant facility and other shutdown costs [Member]
Restructuring Reserve [Roll Forward]
Beginning restructuring liability			3
Restructuring expense			6
Restructuring utilized/paid			8
Ending restructuring liability	1		1
Start-up and moving costs [Member]
Restructuring Reserve [Roll Forward]
Beginning restructuring liability			0
Restructuring expense			7
Restructuring utilized/paid			7
Ending restructuring liability	0		0
Automation Solutions [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	15	9	26	26
Commercial & Residential Solutions [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	5	4	13	11
Climate Technologies [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	4	4	8	11
Tools & Home Products [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	1	0	5	0
Corporate [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	$ 0	$ 1	$ 1	$ 1