Document and Entity Information - USD ($) $ / shares in Units, $ in Billions	12 Months Ended
	Sep. 30, 2017	Oct. 31, 2017	Mar. 31, 2017	Sep. 30, 2016	Sep. 02, 2016
Document Documentand Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Sep. 30, 2017
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	FY
Trading Symbol	JCI
Entity Registrant Name	JOHNSON CONTROLS INTERNATIONAL PLC
Entity Central Index Key	0000833444
Current Fiscal Year End Date	--09-30
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		925,435,012
Entity Public Float			$ 39.5
Ordinary shares, par value	$ 0.01			$ 0.01	$ 1.00