Nature of Operations	12 Months Ended
Nature of Operations	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	Nature of Operations CBRE Group, Inc., a Delaware corporation (which may be referred to in these financial statements as “the company,” “we,” “us” and “our”), was incorporated on February 20, 2001. We are the world’s largest commercial real estate services and investment firm, based on 2020 revenue, with leading global market positions in our leasing, property sales, occupier outsourcing and valuation businesses. Our business is focused on providing services to real estate investors and occupiers. For investors, we provide capital markets (property sales, mortgage origination, sales and servicing), property leasing, investment management, property management, valuation and development services, among others. For occupiers, we provide facilities management, project management, transaction (both property sales and leasing) and consulting services, among others. We generate revenue from both management fees (large multi-year portfolio and per-project contracts) and commissions on transactions. As of December 31, 2020, the company has more than 100,000 employees (excluding affiliates) serving clients in more than 100 countries providing services under the following brand names: “CBRE” (real estate advisory and outsourcing services); “CBRE Global Investors” (investment management); “Trammell Crow Company” (U.S. development); “Telford Homes” (U.K. development) and “Hana” (flexible-space solutions). In 2020, CBRE sponsored a special purpose acquisition company (SPAC), CBRE Acquisition Holdings, Inc. (CBRE Acquisition Holdings), which has the sole purpose of acquiring a privately held company with significant growth potential and to create value by supporting the company in the public markets. The company that it acquires will operate in an industry that will benefit from the experience, expertise and operating skills of CBRE. CBRE Acquisition Holdings trades on the New York Stock Exchange under the symbols “CBAH,” “CBAH.U,” and “CBAH.W.” Considerations Related to the Covid-19 Pandemic From 2010 to early 2020, commercial real estate markets had generally been characterized by increased demand for space, falling vacancies, higher rents and strong capital flows, leading to solid property sales and leasing activity. This healthy backdrop changed abruptly in the first quarter of 2020 with the emergence of the novel coronavirus (Covid-19) and resultant sharp contraction of economic activity across much of the world. There has been a significant impact on commercial real estate markets, as many property owners and occupiers have put transactions on hold and withdrawn existing mandates, sharply reducing sales and leasing volumes. We expect to see the highly challenging operating environment continue, as Covid-19 caseloads remain elevated across our major markets, business travel and face-to-face business dealings are limited and the overwhelming majority of workers remain out of their offices. The recovery of real estate markets around the world remain uncertain as of the date of this report. The effects of Covid-19 adversely impacted our financial position, results of operations, and cash flows for fiscal year 2020. The consolidated financial statements and related notes presented herein reflect our current estimates and assumptions that affect the reported amounts of assets and liabilities and related disclosures as of the date of the consolidated financial statements and reported amounts of sales and expenses during the reporting periods presented. See Note 7 (Fair Value Measurements), Note 9 (Goodwill and Other Intangible Assets) and Note 13 (Commitments and Contingencies) for further discussion of Covid-19 considerations.