Restructuring (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Restructuring Reserve [Roll Forward]
Beginning restructuring liability			$ 52
Restructuring expense	$ 10	$ 9	20	$ 24
Restructuring utilized/paid			34
Ending restructuring liability	38		38
Severance and benefits [Member]
Restructuring Reserve [Roll Forward]
Beginning restructuring liability			46
Restructuring expense			10
Restructuring utilized/paid			22
Ending restructuring liability	34		34
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			4
Restructuring utilized/paid			5
Ending restructuring liability	2		2
Start-up and moving costs [Member]
Restructuring Reserve [Roll Forward]
Beginning restructuring liability			0
Restructuring expense			4
Restructuring utilized/paid			4
Ending restructuring liability	0		0
Automation Solutions [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	6	7	11	17
Commercial & Residential Solutions [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	3	2	8	7
Climate Technologies [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	1	2	4	7
Tools & Home Products [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	2	0	4	0
Corporate [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	$ 1	$ 0	$ 1	$ 0