Secured and Unsecured Debt of the Operating Partnership - Unsecured Senior Notes, Unsecured Revolving Credit Facility and Term Loan Facility (Details) - Kilroy Realty L.P.	3 Months Ended	12 Months Ended
Mar. 31, 2024 USD ($) extension_option	Dec. 31, 2023 USD ($) extension_option
Revolving Credit Facility and Term Loan Facility \| Adjusted SOFR \| Unsecured Revolving Credit Facility
Terms of the Borrowing Facilities
Variable rate (percent)	0.10%	0.10%
Revolving Credit Facility \| Unsecured Revolving Credit Facility
Terms of the Borrowing Facilities
Outstanding borrowings	$ 0	$ 0
Remaining borrowing capacity	1,100,000,000	1,100,000,000
Total borrowing capacity	$ 1,100,000,000	$ 1,100,000,000
Interest rate (percent)	6.34%	6.38%
Facility fee-annual rate (percent)	0.20%	0.20%
Outstanding letters of credit	$ 5,200,000	$ 5,200,000
Contingent additional borrowings	$ 500,000,000	$ 500,000,000
Reduction interest rate	0.01%	0.01%
Unamortized deferred financing costs	$ 15,200,000	$ 3,200,000
Number of extension options \| extension_option	2	2
Extension period (in months)	6 months	6 months
Revolving Credit Facility \| SOFR \| Unsecured Revolving Credit Facility
Terms of the Borrowing Facilities
Variable rate (percent)	0.90%	0.90%
Term Loan Facility \| 2022 Term Loan Facility
Terms of the Borrowing Facilities
Outstanding borrowings	$ 120,000,000	$ 520,000,000
Remaining borrowing capacity	0	0
Total borrowing capacity	$ 120,000,000	$ 520,000,000
Interest rate (percent)	6.38%	6.41%
Facility fee-annual rate (percent)	0.20%	0.20%
Unamortized deferred financing costs		$ 2,300,000
Extension period (in months)	12 months	12 months
Term Loan Facility \| SOFR \| 2024 Term Loan Facility
Terms of the Borrowing Facilities
Variable rate (percent)	0.95%
Term Loan Facility \| SOFR \| 2022 Term Loan Facility
Terms of the Borrowing Facilities
Variable rate (percent)	0.95%	0.95%
Unsecured debt, net \| 2024 Term Loan Facility
Terms of the Borrowing Facilities
Number of extension options \| extension_option	2
Extension period (in months)	12 months
Unsecured debt, net \| 2022 Term Loan Facility
Terms of the Borrowing Facilities
Number of extension options \| extension_option	2
Extension period (in months)	12 months
Line of Credit \| 2024 Term Loan Facility
Terms of the Borrowing Facilities
Outstanding borrowings	$ 200,000,000
Remaining borrowing capacity	0
Total borrowing capacity	$ 200,000,000
Interest rate (percent)	6.37%
Contingent additional borrowings	$ 130,000,000
Unamortized deferred financing costs	$ 3,000,000

Debt Instrument, Contingent Additional Borrowings

No definition available.

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Balance Type:	credit
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- Definition

Debt instrument, Reduction Interest Rate

+ References

No definition available.

+ Details

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- Definition

Line of Credit, Extension Period

+ References

No definition available.

+ Details

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- Definition

Line of Credit, Number of Extension Options

+ References

No definition available.

+ Details

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- 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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- Definition

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

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions 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
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-SubTopic 10
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1

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Balance Type:	credit
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- References

No definition available.

+ Details

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- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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Data Type:	dtr-types:percentItemType
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- Definition

The effective interest rate at the end of the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

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- 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

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

No definition available.

+ Details

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