CONSOLIDATED STATEMENTS OF CAPITAL (KILROY REALTY, L.P.) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	$ 86,660	$ 53,975	$ 59,383	$ 53,493	$ 42,880	$ 507,411	$ 200,018	$ 603,784
Non-cash amortization of share-based compensation (Note 8)	10,287	9,665	6,598	11,477	11,193	9,604
Settlement of restricted stock units	0	0	0	0	0	0
Contributions from noncontrolling interests in consolidated property partnerships							0	1,591
Distributions to noncontrolling interests in consolidated property partnerships	(5,700)	(6,948)	(14,842)	(7,922)	(4,692)	(11,680)
Noncontrolling Interests in Consolidated Property Partnerships
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income	6,903	6,870	6,255	6,465	7,041	9,780
Contributions from noncontrolling interests in consolidated property partnerships				1,591
Distributions to noncontrolling interests in consolidated property partnerships	(5,700)	(6,948)	(14,842)	(7,922)	(4,692)	(11,680)
Kilroy Realty L.P.
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	5,652,551	5,665,761	5,689,870	5,693,465	5,702,892	5,277,321	5,689,870	5,277,321
Net income	86,660	53,975	59,383	53,493	42,880	507,411	200,018	603,784
Issuance of share-based compensation awards	505	635	1,942	650	645	1,950
Non-cash amortization of share-based compensation (Note 8)	10,287	9,665	6,598	11,477	11,193	9,604
Settlement of restricted stock units	0	0	0	0	0	0
Repurchase of common units and restricted stock units	(267)	(8,660)	(13,994)	(282)		(21,137)
Contributions from noncontrolling interests in consolidated property partnerships							0	1,591
Contributions from noncontrolling interests in consolidated property partnerships				(1,591)
Distributions to noncontrolling interests in consolidated property partnerships	(5,700)	(6,948)	(14,842)	(7,922)	(4,692)	(11,680)
Distributions declared per common unit	(64,259)	(61,877)	(63,196)	(61,834)	(59,453)	(60,577)
Ending balance	$ 5,679,777	$ 5,652,551	$ 5,665,761	$ 5,690,638	$ 5,693,465	$ 5,702,892	$ 5,679,777	$ 5,690,638
Kilroy Realty L.P. | Partners’ Capital
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance (in shares)	118,021,544	117,866,654	117,614,743	117,604,784	117,600,944	117,186,401	117,614,743	117,186,401
Beginning balance	$ 5,466,183	$ 5,478,800	$ 5,493,806	$ 5,500,753	$ 5,512,175	$ 5,079,818	$ 5,493,806	$ 5,079,818
Net income	80,421	47,620	53,644	47,488	36,193	502,517
Issuance of share-based compensation awards	505	635	1,942	650	645	1,950
Non-cash amortization of share-based compensation (Note 8)	$ 10,287	$ 9,665	$ 6,598	$ 11,477	$ 11,193	$ 9,604
Settlement of restricted stock units (in shares)	11,930	273,382	459,050	11,743	3,840	769,701
Repurchase of common units, stock options and restricted stock units (in shares)	(5,447)	(118,492)	(207,139)	(4,270)		(355,158)
Repurchase of common units and restricted stock units	$ (267)	$ (8,660)	$ (13,994)	$ (282)		$ (21,137)
Distributions declared per common unit	$ (64,259)	$ (61,877)	$ (63,196)	$ (61,834)	$ (59,453)	$ (60,577)
Ending balance (in shares)	118,028,027	118,021,544	117,866,654	117,612,257	117,604,784	117,600,944	118,028,027	117,612,257
Ending balance	$ 5,492,870	$ 5,466,183	$ 5,478,800	$ 5,498,252	$ 5,500,753	$ 5,512,175	$ 5,492,870	$ 5,498,252
Kilroy Realty L.P. | Noncontrolling Interests in Consolidated Property Partnerships
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning balance	186,368	186,961	196,064	192,712	190,717	197,503	196,064	197,503
Net income	6,239	6,355	5,739	6,005	6,687	4,894
Contributions from noncontrolling interests in consolidated property partnerships				1,591
Distributions to noncontrolling interests in consolidated property partnerships	(5,700)	(6,948)	(14,842)	(7,922)	(4,692)	(11,680)
Ending balance	$ 186,907	$ 186,368	$ 186,961	$ 192,386	$ 192,712	$ 190,717	$ 186,907	$ 192,386