Document and Entity Information	3 Months Ended
	Dec. 31, 2018 shares
Document and Entity Information [Abstract]
Entity Registrant Name	JOHNSON CONTROLS INTERNATIONAL PLC
Entity Central Index Key	0000833444
Current Fiscal Year End Date	--09-30
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	JCI
Amendment Flag	false
Entity Common Stock, Shares Outstanding	912,713,145