Secured and Unsecured Debt of the Operating Partnership - Unsecured Revolving Credit Facility and Term Loan Facility (Details)	1 Months Ended	12 Months Ended
	Oct. 31, 2022 USD ($) extension_option	Dec. 31, 2023 USD ($) extension_option	Dec. 31, 2022 USD ($) extension_option	Dec. 31, 2021 USD ($)	Mar. 31, 2023 USD ($)
Debt Instrument [Line Items]
Proceeds from the issuance of unsecured debt		$ 0	$ 0	$ 449,807,000
Kilroy Realty L.P.
Debt Instrument [Line Items]
Proceeds from the issuance of unsecured debt		0	0	$ 449,807,000
Revolving credit facility | Kilroy Realty L.P.
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 1,100,000,000	$ 1,100,000,000
Number of extension options | extension_option		2	2
Extension period (in months)		6 months	6 months
Contingent additional borrowings		$ 500,000,000	$ 500,000,000
Revolving credit facility | Kilroy Realty L.P. | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Variable rate (percent)		0.90%	0.90%
Unsecured debt | Unsecured Term Loan Facility
Debt Instrument [Line Items]
Number of extension options | extension_option	2
Extension period (in months)	12 months
Principal amount of debt	$ 400,000,000
Proceeds from the issuance of unsecured debt	$ 200,000,000
Unsecured debt | Kilroy Realty L.P. | Unsecured Term Loan Facility
Debt Instrument [Line Items]
Number of extension options | extension_option		2	2
Extension period (in months)		12 months	12 months
Principal amount of debt					$ 520,000,000
Unsecured debt | Kilroy Realty L.P. | Unsecured Term Loan Facility | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Variable rate (percent)	0.95%
Line of credit | Kilroy Realty L.P. | Unsecured Term Loan Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 520,000,000	$ 400,000,000
Contingent additional borrowings	$ 100,000,000	$ 130,000,000	$ 100,000,000
Line of credit | Kilroy Realty L.P. | Unsecured Term Loan Facility | Secured Overnight Financing Rate (SOFR)
Debt Instrument [Line Items]
Variable rate (percent)		0.95%	0.95%