Line of Credit Facility, Accordion Feature, Increase Limit

No definition available.

Name:	cbre_LineOfCreditFacilityAccordionFeatureIncreaseLimit
Namespace Prefix:	cbre_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum leverage ratio during first four quarter that qualified acquisition is consummated.

+ References

No definition available.

+ Details

Name:	cbre_MaximumLeverageRatioDuringFirstFourQuarterThatQualifiedAcquisitionIsConsummated
Namespace Prefix:	cbre_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the maximum ratio of debt less available cash to earnings before interest, taxes, depreciation and amortization (EBITDA) allowed in the reporting entity's credit agreement.

+ References

No definition available.

+ Details

Name:	cbre_MaximumLeverageRatioOfDebtToEarningsBeforeInterestTaxDepreciationAndAmortizationExpressedInPercentage
Namespace Prefix:	cbre_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

This element represents the minimum ratio of earnings before interest, taxes, depreciation and amortization (EBITDA) to total interest expense required in the reporting entity's credit agreement.

+ References

No definition available.

+ Details

Name:	cbre_MinimumCoverageRatioOfEarningsBeforeInterestTaxDepreciationAndAmortizationToInterestExpenseExpressedInPercentage
Namespace Prefix:	cbre_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value of the amount outstanding under the credit facility.

+ References

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+ Details

Name:	us-gaap_LineOfCreditFacilityFairValueOfAmountOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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+ Details

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Balance Type:	credit
Period Type:	instant

- Details

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Period Type:

- Details

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Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
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Balance Type:
Period Type:

- Details

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Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
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Period Type:

- Details

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Balance Type:
Period Type:

- Details

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- Details

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- Details

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- Details

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- Details

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Long-Term Debt and Short-Term Borrowings - Revolving Credit Facility Narrative (Details) £ in Millions, $ in Millions			12 Months Ended
	Jul. 10, 2023	Aug. 05, 2022 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 GBP (£)	Dec. 31, 2022 USD ($)
Debt Instrument [Line Items]
Debt agreement term			11 years
Letters of credit outstanding amount			$ 236.9
Revolving credit facility, with interest ranging from 5.03% to 5.23%			0.0		$ 178.0
Revolving Credit Facility, Maturity Date August 5, 2027 \| Senior Notes
Debt Instrument [Line Items]
Minimum coverage ratio of EBITDA to total interest expense expressed in percentage		2.00%
Maximum leverage ratio of total debt less available cash to EBITDA expressed in percentage		4.25%
Maximum leverage ratio during first four quarter that qualified acquisition is consummated		4.75%
2023 Credit Agreement with Wells Fargo
Debt Instrument [Line Items]
Interest rate	1000.00%
Minimum coverage ratio of EBITDA to total interest expense expressed in percentage	2.00%
Maximum leverage ratio of total debt less available cash to EBITDA expressed in percentage	4.25%
Maximum leverage ratio during first four quarter that qualified acquisition is consummated	4.75%
2023 Credit Agreement with Wells Fargo \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	100.00%
2023 Credit Agreement with Wells Fargo \| Fed Funds Effective Rate Overnight Index Swap Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		500.00%
Revolving credit facility \| Revolving Credit Facility, Maturity Date August 5, 2027
Debt Instrument [Line Items]
Debt agreement term		5 years
Amounts available to borrow under credit agreement		$ 3,500.0
Interest rate		1000.00%
Revolving credit facility \| Revolving Credit Facility, Maturity Date August 5, 2027 \| Line of Credit
Debt Instrument [Line Items]
Letters of credit outstanding amount		$ 300.0
Revolving credit facility \| Revolving Credit Facility, Maturity Date August 5, 2027 \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		1.00%
Revolving credit facility \| Revolving Credit Facility, Maturity Date August 5, 2027 \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		0.63%
Revolving credit facility \| Revolving Credit Facility, Maturity Date August 5, 2027 \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		1.10%
Revolving credit facility \| Revolving Credit Facility, Maturity Date August 5, 2027 \| Base Rate \| Minimum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		0.00%
Revolving credit facility \| Revolving Credit Facility, Maturity Date August 5, 2027 \| Base Rate \| Maximum
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		0.10%
Revolving credit facility \| Revolving Credit Facility, Maturity Date August 5, 2027 \| Fed Funds Effective Rate Overnight Index Swap Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	500.00%
Revolving credit facility \| 2019 Credit Agreement
Debt Instrument [Line Items]
Line of credit facility outstanding			0.0
Revolving credit facility \| 2019 Credit Agreement \| Line of Credit
Debt Instrument [Line Items]
Letters of credit outstanding amount			0.0
Revolving credit facility \| Revolving Credit Facility, Maturity Date March 31, 2027 \| Turner & Townsend
Debt Instrument [Line Items]
Amounts available to borrow under credit agreement \| £				£ 120.0
Increase limit \| £				20.0
Revolving credit facility \| Revolving Credit Facility, Maturity Date January 31, 2024 \| Turner & Townsend
Debt Instrument [Line Items]
Revolving credit facility, with interest ranging from 5.03% to 5.23%			$ 10.2	£ 8.0
Revolving credit facility \| Revolving Credit Facility, Maturity Date January 31, 2024 \| SONIA Overnight Rate \| Turner & Townsend
Debt Instrument [Line Items]
Basis spread on variable rate (percent)			0.75%