Cover - shares	6 Months Ended
	Jun. 30, 2020	Aug. 07, 2020
Document Information
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
Document Transition Report	false
Entity File Number	000-54970
Entity Registrant Name	CORPORATE PROPERTY ASSOCIATES 18 – GLOBAL INCORPORATED
Entity Incorporation, State	MD
Entity Tax Identification Number	90-0885534
Entity Address, Street	50 Rockefeller Plaza
Entity Address, City	New York,
Entity Address, State	NY
Entity Address, Postal Zip Code	10020
City Area Code	212
Local Phone Number	492-1100
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001558235
Class A
Document Information
Entity Common Stock, Shares Outstanding		118,756,873
Class C
Document Information
Entity Common Stock, Shares Outstanding		32,466,931