Ratio of EBITDA as defined in the Credit Agreement to interest expense calculated over a trailing twelve month period.

No definition available.

Name:	cbre_CoverageRatioOfEarningsBeforeInterestTaxDepreciationAndAmortizationToInterestExpense
Namespace Prefix:	cbre_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Principal Amount Issued, Percentage Of Face Value

+ References

No definition available.

+ Details

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

- Definition

Leverage ratio of total debt to EBITDA.

+ References

No definition available.

+ Details

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Namespace Prefix:	cbre_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit Facility, Maximum Borrowing Capacity Increase (Decrease)

+ References

No definition available.

+ Details

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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-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

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

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

- Definition

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

+ References

+ 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

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

- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

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

- 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
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-Paragraph 1
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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 cash outflow for the settlement of obligation drawn from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with maturities due beyond one year or the operating cycle, if longer.

+ References

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Balance Type:	credit
Period Type:	duration

- Details

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Long-Term Debt and Short-Term Borrowings - Long-Term Debt - Narrative (Detail)			3 Months Ended
	Mar. 04, 2019 USD ($)	Aug. 13, 2015 USD ($)	Mar. 31, 2022 USD ($)	Mar. 31, 2022 EUR (€)	Jul. 09, 2021 USD ($)	Mar. 18, 2021 USD ($)
2021 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%
Coverage ratio of EBITDA to total interest expense			52.16	52.16
Leverage ratio of total debt less available cash to EBITDA			0.23	0.23
2.5% Senior Notes \| Senior Notes
Debt Instrument [Line Items]
Face amount of debt						$ 500,000,000
Interest rate of long-term debt			2.50%	2.50%		2.50%
Principal amount of debt issued, percentage of face value						98.451%
4.875% Senior Notes \| Senior Notes
Debt Instrument [Line Items]
Face amount of debt		$ 600,000,000
Interest rate of long-term debt		4.875%	4.875%	4.875%
Redemption price percentage		99.24%
Tranche A term loan facility \| 2019 Credit Agreement
Debt Instrument [Line Items]
Repayments on line of credit	$ 300,000,000
Tranche A term loan facility \| 2021 Credit Agreement
Debt Instrument [Line Items]
Face amount of debt \| €				€ 300,000,000
Revolving credit facility \| 2019 Credit Agreement
Debt Instrument [Line Items]
Increase in revolving credit commitment					$ 350,000,000
Revolving credit facility \| 2021 Credit Agreement
Debt Instrument [Line Items]
Amounts available to borrow under credit agreement			$ 3,150,000,000
Euro term loan facility \| 2021 Credit Agreement
Debt Instrument [Line Items]
Face amount of debt \| €				€ 400,000,000