Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Jun. 30, 2014	Mar. 23, 2015
Document Entity Information [Abstract]
Document Type	10-K
Document Period End Date	Dec. 31, 2014
Amendment Flag	false
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001558235
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Registrant Name	Corporate Property Associates 18 Global Incorporated
Entity Voluntary Filers	No
Entity Well Known Seasoned Issuer	No
Entity Public Float		$ 0
Class A
Document Entity Information [Abstract]
Entity Common Stock Shares Outstanding			100,794,838
Class C
Document Entity Information [Abstract]
Entity Common Stock Shares Outstanding			27,266,757