| Cover | Sep. 10, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Sep. 10, 2021 |
| Entity Registrant Name | CORPORATE PROPERTY ASSOCIATES 18 – GLOBAL INCORPORATED |
| Entity Incorporation, State | MD |
| Entity File Number | 000-54970 |
| Entity Tax Identification Number | 90-0885534 |
| Entity Address, Street Address | One Manhattan West, 395 9th Avenue, 58th Floor |
| Entity Address, City | New York, |
| Entity Address, State | NY |
| Entity Address, Zip Code | 10001 |
| City Area Code | 492-1100 |
| Local Phone Number | 212 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001558235 |
| Amendment Flag | false |
