Partners' Capital of the Operating Partnership (Details) - shares	9 Months Ended		12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Operating Partnership
General Partners' Capital Account [Abstract]
Company owned general partnership interest (percent)	99.00%	99.00%	99.00%
Kilroy Realty L.P. | Common Units
General Partners' Capital Account [Abstract]
Company owned common units in the Operating Partnership (in units)	116,877,453	116,461,683	116,464,169
Non-affiliated investors and other common units of the Operating Partnership (in units)	1,150,574		1,150,574
Non-Affiliated Investors | Operating Partnership
General Partners' Capital Account [Abstract]
Company owned general partnership interest (percent)	1.00%	1.00%	1.00%
Non-Affiliated Investors | Common Units
General Partners' Capital Account [Abstract]
Non-affiliated investors and other common units of the Operating Partnership (in units)	1,150,574	1,150,574	1,150,574