Cover Page - shares	3 Months Ended
	Mar. 31, 2021	Apr. 23, 2021
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2021
Document Transition Report	false
Entity File Number	1-12675
Entity Registrant Name	KILROY REALTY CORPORATION
Entity Incorporation, State Code	MD
Entity Tax Identification Number	95-4598246
Entity Address, Address Line One	12200 W. Olympic Boulevard
Entity Address, Address Line Two	Suite 200
Entity Address, City or Town	Los Angeles
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	90064
City Area Code	310
Local Phone Number	481-8400
Title of 12(b) Security	Common Stock, $.01 par value
Security Exchange Name	NYSE
Trading Symbol	KRC
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		116,450,370
Entity Central Index Key	0001025996
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false
Kilroy Realty L.P. [Member]
Entity Information [Line Items]
Entity File Number	000-54005
Entity Registrant Name	KILROY REALTY, L.P.
Entity Incorporation, State Code	DE
Entity Tax Identification Number	95-4612685
Title of 12(g) Security	Common Units Representing Limited Partnership Interests
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Central Index Key	0001493976