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, 2023 USD ($) extension_option	Dec. 31, 2022 USD ($)
Revolving Credit Facility
Terms of the Credit Facility
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)	5.87%	5.20%
Facility fee-annual rate (percent)	0.20%	0.20%
Contingent additional borrowings	$ 500,000,000	$ 500,000,000
Unamortized deferred financing costs	$ 4,800,000	$ 5,300,000
Number of extension options | extension_option	2
Extension period (in months)	6 months
Revolving Credit Facility | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Terms of the Credit Facility
Variable rate (percent)	0.90%	0.90%
Revolving Credit Facility | Adjusted SOFR
Terms of the Credit Facility
Variable rate (percent)	0.10%	0.10%
Term Loan Facility | Unsecured Term Loan Facility
Terms of the Credit Facility
Outstanding borrowings	$ 350,000,000	$ 200,000,000
Remaining borrowing capacity	170,000,000	200,000,000
Total borrowing capacity	$ 520,000,000	$ 400,000,000
Interest rate (percent)	5.77%	5.23%
Facility fee-annual rate (percent)	0.20%	0.20%
Contingent additional borrowings	$ 130,000,000	$ 100,000,000
Unamortized deferred financing costs	$ 4,600,000	$ 4,500,000
Number of extension options | extension_option	2
Extension period (in months)	12 months
Term Loan Facility | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | Unsecured Term Loan Facility
Terms of the Credit Facility
Variable rate (percent)	0.95%	0.95%