Partners' Capital of the Operating Partnership (Details) - shares	3 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Operating Partnership
General Partners' Capital Account [Abstract]
Ownership 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)	116,716,080	116,450,370	116,464,169
Noncontrolling common units of the Operating Partnership (in units)	1,150,574		1,150,574
Non-Affiliated Investors | Operating Partnership
General Partners' Capital Account [Abstract]
Ownership interest (percent)	1.00%	1.00%	1.00%
Non-Affiliated Investors | Common Units
General Partners' Capital Account [Abstract]
Noncontrolling common units of the Operating Partnership (in units)	1,150,574	1,150,574	1,150,574