Subsequent Event	12 Months Ended
Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Event	Subsequent EventAs described in Note 10, the company made a $50.0 million non-controlling investment in Industrious in the fourth quarter of 2020. On February 19, 2021, the company made an additional non-controlling investment in Industrious, for approximately $150.0 million in the form of primary and secondary shares, as well as shares issued in anticipation of Industrious closing on the transfer of Hana in the second quarter of 2021. Following this transaction, CBRE holds a 35% interest in Industrious. In addition, CBRE has entered into a series of agreements to acquire additional shares, whereby the company will increase its interest in Industrious from 35% to 40%.

The entire disclosure for significant events or transactions that occurred after the balance sheet date through the date the financial statements were issued or the date the financial statements were available to be issued. Examples include: the sale of a capital stock issue, purchase of a business, settlement of litigation, catastrophic loss, significant foreign exchange rate changes, loans to insiders or affiliates, and transactions not in the ordinary course of business.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-URI http://asc.fasb.org/topic&trid=2122774

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 855
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6842918&loc=SL6314017-165662

Name:	us-gaap_SubsequentEventsTextBlock
Namespace Prefix:	us-gaap_
Data Type:	nonnum:textBlockItemType
Balance Type:	na
Period Type:	duration