| Document and Entity Information | Jul. 26, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001138118 |
| Document Type | 8-K |
| Document Period End Date | Jul. 26, 2021 |
| Entity Registrant Name | CBRE GROUP, INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-32205 |
| Entity Tax Identification Number | 94-3391143 |
| Entity Address, Address Line One | 400 South Hope Street |
| Entity Address, Address Line Two | 25th Floor |
| Entity Address, City or Town | Los Angeles |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 90071 |
| City Area Code | (213) |
| Local Phone Number | 613-3333 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Class A Common Stock, $0.01 par value per share |
| Trading Symbol | CBRE |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
