Credit Spread Adjustment Rate

No definition available.

Name:	cbre_CreditSpreadAdjustmentRate
Namespace Prefix:	cbre_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit Facility, Accordion Feature, Increase Limit

+ References

No definition available.

+ Details

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

- Definition

Long term debt percentage spread over daily interest rate.

+ References

No definition available.

+ Details

Name:	cbre_LongTermDebtPercentageSpreadOverDailyInterestRate
Namespace Prefix:	cbre_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Long term debt percentage spread over fixed interest rate.

+ References

No definition available.

+ Details

Name:	cbre_LongTermDebtPercentageSpreadOverFixedInterestRate
Namespace Prefix:	cbre_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- 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-types: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-types: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-types: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

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
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.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI https://asc.fasb.org/extlink&oid=123594938&loc=d3e13433-108611

+ 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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ 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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(13))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3255-108585

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentAxis=cbre_TwoThousandTwentyOneCreditAgreementMember
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Balance Type:
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- Details

Name:	us-gaap_DebtInstrumentAxis=cbre_RevolvingCreditFacilityMaturityDateAugust52027Member
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Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_SeniorNotesMember
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Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=cbre_TurnerTownsendHoldingsLimitedMember
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- Details

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Name:	srt_RangeAxis=srt_MaximumMember
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- Details

Name:	srt_ConsolidatedEntitiesAxis=cbre_CanadianAustralianAndNewZealandSubsidiariesMember
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- Details

Name:	srt_ConsolidatedEntitiesAxis=cbre_UnitedKingdomSubsidiaryMember
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Balance Type:
Period Type:

- Details

Name:	us-gaap_ShortTermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
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- Details

Name:	us-gaap_DebtInstrumentAxis=cbre_TwoThousandNineteenCreditAgreementMember
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- Details

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Long-Term Debt and Short-Term Borrowings - Revolving Credit Facility Narrative (Details) € in Millions		12 Months Ended
	Aug. 05, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 EUR (€)	Jan. 01, 2022	Dec. 31, 2021 USD ($)	Dec. 31, 2021 EUR (€)	May 21, 2021 USD ($)
Debt Instrument [Line Items]
Debt agreement term		10 years
Letters of credit outstanding amount		$ 206,800,000
Revolving credit facility, with interest ranging from 5.03% to 5.23%		$ 178,000,000			$ 0
2021 Credit Agreement
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%
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%
Revolving credit facility \| Turner & Townsend
Debt Instrument [Line Items]
Revolving credit facility, with interest ranging from 5.03% to 5.23%					$ 27,000,000	€ 20.0
Revolving credit facility \| 2021 Credit Agreement
Debt Instrument [Line Items]
Debt agreement term	5 years
Amounts available to borrow under credit agreement							$ 3,150,000,000
Credit spread adjustment rate				0.0326%
Revolving credit facility \| 2021 Credit Agreement \| Minimum
Debt Instrument [Line Items]
Credit Agreement applicable fixed rate spread		0.68%
Credit Agreement applicable daily rate spread		0.00%
Revolving credit facility \| 2021 Credit Agreement \| Maximum
Debt Instrument [Line Items]
Credit Agreement applicable fixed rate spread		1.075%
Credit Agreement applicable daily rate spread		0.075%
Revolving credit facility \| 2021 Credit Agreement \| Canadian, Australian and New Zealand subsidiaries
Debt Instrument [Line Items]
Amounts available to borrow under credit agreement		$ 200,000,000
Revolving credit facility \| 2021 Credit Agreement \| U.K. subsidiaries
Debt Instrument [Line Items]
Amounts available to borrow under credit agreement		320,000,000
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	$ 3,500,000,000
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	$ 300,000,000
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 \| Minimum \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	0.63%
Revolving credit facility \| Revolving Credit Facility, Maturity Date August 5, 2027 \| Minimum \| Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	0.00%
Revolving credit facility \| Revolving Credit Facility, Maturity Date August 5, 2027 \| Maximum \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.10%
Revolving credit facility \| Revolving Credit Facility, Maturity Date August 5, 2027 \| Maximum \| Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	0.10%
Revolving credit facility \| 2019 Credit Agreement
Debt Instrument [Line Items]
Initial borrowing	$ 220,000,000
Line of credit facility outstanding		178,000,000
Revolving credit facility \| 2019 Credit Agreement \| Line of Credit
Debt Instrument [Line Items]
Letters of credit outstanding amount	$ 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, with interest ranging from 5.03% to 5.23%		$ 31,900,000	26.3
Revolving credit facility \| Revolving Credit Facility, Maturity Date November 11, 2022 \| Turner & Townsend \| SONIA Overnight Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		0.75%
Revolving credit facility \| Revolving Credit Facility, Maturity Date November 11, 2022 \| Minimum \| Turner & Townsend \| SONIA Overnight Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		1.0266%
Revolving credit facility \| Revolving Credit Facility, Maturity Date November 11, 2022 \| Maximum \| Turner & Townsend \| SONIA Overnight Rate
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		2.0266%
Revolving credit facility \| Revolving Credit Facility, Maturity Date May 5 2022 \| Turner & Townsend
Debt Instrument [Line Items]
Amounts available to borrow under credit agreement \| €			€ 80.0