Restructuring (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2018
Restructuring Reserve [Roll Forward]
Beginning restructuring liability	$ 65
Restructuring expense	15	$ 11
Restructuring paid	18
Ending restructuring liability	62
Severance and benefits [Member]
Restructuring Reserve [Roll Forward]
Beginning restructuring liability	60
Restructuring expense	10
Restructuring paid	14
Ending restructuring liability	56
Lease and other contract terminations [Member]
Restructuring Reserve [Roll Forward]
Beginning restructuring liability	4
Restructuring expense	2
Restructuring paid	1
Ending restructuring liability	5
Vacant facility and other shutdown costs [Member]
Restructuring Reserve [Roll Forward]
Beginning restructuring liability	1
Restructuring expense	1
Restructuring paid	1
Ending restructuring liability	1
Start-up and moving costs [Member]
Restructuring Reserve [Roll Forward]
Beginning restructuring liability	0
Restructuring expense	2
Restructuring paid	2
Ending restructuring liability	0
Automation Solutions [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	10	6
Commercial & Residential Solutions [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	5	5
Climate Technologies [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	5	4
Tools & Home Products [Member]
Restructuring Reserve [Roll Forward]
Restructuring expense	$ 0	$ 1
Scenario, Forecast [Member]
Restructuring Reserve [Roll Forward]
Expected fiscal year restructuring expense			$ 85