Secured and Unsecured Debt of the Operating Partnership - Unsecured Senior Notes - Private Placement (Details) - Kilroy Realty L.P. [Member] - USD ($)		9 Months Ended
May 11, 2018	Sep. 30, 2018
Debt Instrument [Line Items]
Long-term debt, gross		$ 2,891,725,000
Unsecured debt [Member] \| 4.30% Series A Senior Note
Debt Instrument [Line Items]
Debt, principal	$ 50,000,000	0
Debt issuance		0
Stated coupon rate	4.30%
Debt instrument, maturity date	Jul. 18, 2026
Unsecured debt [Member] \| 4.35% Series B Senior Note [Member]
Debt Instrument [Line Items]
Debt, principal		0
Debt issuance		$ 0
Long-term debt, gross	$ 200,000,000
Stated coupon rate	4.35%
Debt instrument, maturity date	Oct. 18, 2026
Private placement [Member] \| Unsecured debt [Member] \| Series A and B Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Operating partnership, payment percent		5.00%
Operating partnership, total payment percentage		100.00%

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- Definition

Operating Partnership, Total Payment Percentage

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No definition available.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

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- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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