Income Per Share Information - Calculation of Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Basic Income Per Share
Net income attributable to CBRE Group, Inc. stockholders	$ 1,836,574	$ 751,989	$ 1,282,357
Weighted average shares outstanding for basic income per share (in shares)	335,232,840	335,196,296	335,795,654
Basic income per share attributable to CBRE Group, Inc. shareholders (in USD per share)	$ 5.48	$ 2.24	$ 3.82
Diluted Income Per Share
Net income attributable to CBRE Group, Inc. stockholders	$ 1,836,574	$ 751,989	$ 1,282,357
Weighted average shares outstanding for basic income per share (in shares)	335,232,840	335,196,296	335,795,654
Dilutive effect of contingently issuable shares (in shares)	4,484,561	3,195,914	4,727,217
Weighted average shares outstanding for diluted income per share (in shares)	339,717,401	338,392,210	340,522,871
Diluted income per share attributable to CBRE Group, Inc. shareholders (in USD per share)	$ 5.41	$ 2.22	$ 3.77