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

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

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cbre_TwoThousandTwentyOneCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=cbre_CanadianAustralianAndNewZealandSubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=cbre_UnitedKingdomSubsidiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cbre_RevolvingCreditFacilityMaturityDateMarch312027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=cbre_TurnerTownsendHoldingsLimitedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cbre_TwoThousandNineteenCreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cbre_RevolvingCreditFacilityMaturityDateNovember112022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=cbre_SONIAOvernightRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cbre_RevolvingCreditFacilityMaturityDateFebruary212023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-Term Debt and Short-Term Borrowings - Short Term Borrowings - Narrative (Details) € in Millions		3 Months Ended	9 Months Ended
	Aug. 05, 2022 USD ($)	Mar. 31, 2022 EUR (€)	Sep. 30, 2022 USD ($)	Sep. 30, 2022 EUR (€)	Jan. 01, 2022	Dec. 31, 2021 USD ($)	May 21, 2021 USD ($)
Debt Instrument [Line Items]
Letters of credit outstanding amount			$ 177,300,000
Revolving credit facility			$ 283,000,000			$ 0
Revolving Credit Agreement \| 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 Agreement \| Revolving credit facility
Debt Instrument [Line Items]
Debt instrument term	5 years
Amounts available to borrow under credit agreement	$ 3,500,000,000
Additional accordion option	$ 350,000,000
Interest rate (as a percent)	1000.00%
Revolving Credit Agreement \| Revolving credit facility \| Line of Credit
Debt Instrument [Line Items]
Letters of credit outstanding amount	$ 300,000,000
Revolving Credit Agreement \| Revolving credit facility \| Fed Funds Effective Rate Overnight Index Swap Rate
Debt Instrument [Line Items]
Variable rate (as a percent)	0.50%
Revolving Credit Agreement \| Revolving credit facility \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap
Debt Instrument [Line Items]
Variable rate (as a percent)	1.00%
Revolving Credit Agreement \| Revolving credit facility \| Minimum \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap
Debt Instrument [Line Items]
Variable rate (as a percent)	0.63%
Revolving Credit Agreement \| Revolving credit facility \| Minimum \| Base Rate
Debt Instrument [Line Items]
Variable rate (as a percent)	0.00%
Revolving Credit Agreement \| Revolving credit facility \| Maximum \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap
Debt Instrument [Line Items]
Variable rate (as a percent)	1.10%
Revolving Credit Agreement \| Revolving credit facility \| Maximum \| Base Rate
Debt Instrument [Line Items]
Variable rate (as a percent)	0.10%
2021 Credit Agreement \| Revolving credit facility
Debt Instrument [Line Items]
Debt instrument term	5 years
Amounts available to borrow under credit agreement							$ 3,150,000,000
Credit spread adjustment rate					0.0326%
2021 Credit Agreement \| Revolving credit facility \| Minimum
Debt Instrument [Line Items]
Credit agreement applicable fixed rate spread			0.68%
Credit agreement applicable daily rate spread			0.00%
2021 Credit Agreement \| Revolving credit facility \| Maximum
Debt Instrument [Line Items]
Credit agreement applicable fixed rate spread			1.075%
Credit agreement applicable daily rate spread			0.075%
2021 Credit Agreement \| Canadian, Australian and New Zealand subsidiaries \| Revolving credit facility
Debt Instrument [Line Items]
Amounts available to borrow under credit agreement			$ 200,000,000
2021 Credit Agreement \| U.K. subsidiaries \| Revolving credit facility
Debt Instrument [Line Items]
Amounts available to borrow under credit agreement			320,000,000
2027 Credit Agreement \| Revolving credit facility \| Turner & Townsend Holdings Limited
Debt Instrument [Line Items]
Amounts available to borrow under credit agreement \| €		€ 120.0
Additional accordion option \| €		€ 20.0
Revolving credit facility			29,400,000	€ 26.3
2019 Credit Agreement \| Revolving credit facility
Debt Instrument [Line Items]
Initial borrowing	$ 220,000,000
Revolving credit facility	283,000,000
2019 Credit Agreement \| Revolving credit facility \| Line of Credit
Debt Instrument [Line Items]
Letters of credit outstanding amount	$ 0
Revolving Credit Facility, Maturity Date November 11, 2022 \| Revolving credit facility \| Turner & Townsend Holdings Limited
Debt Instrument [Line Items]
Revolving credit facility			22,300,000	20.0
Revolving Credit Facility, Maturity Date November 11, 2022 \| Revolving credit facility \| Turner & Townsend Holdings Limited \| SONIA
Debt Instrument [Line Items]
Variable rate (as a percent)		0.75%
Revolving Credit Facility, Maturity Date February 21, 2023 \| Revolving credit facility \| Turner & Townsend Holdings Limited
Debt Instrument [Line Items]
Revolving credit facility			$ 7,100,000	€ 6.3