Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 17, 2022	Jun. 30, 2021
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity Registrant Name	Brandywine Realty Trust
Entity Incorporation, State or Country Code	MD
Entity File Number	001-9106
Entity Tax Identification Number	23-2413352
Entity Address, Address Line One	2929 Arch Street
Entity Address, Address Line Two	Suite 1800
Entity Address, City or Town	Philadelphia
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	19104
City Area Code	610
Local Phone Number	325-5600
Title of 12(b) Security	Common Shares of Beneficial Interest
Trading Symbol	BDN
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 2,282,260,692
Entity Common Stock, Shares Outstanding		171,383,912
Documents Incorporated by Reference	Portions of the proxy statement for the 2022 Annual Meeting of Shareholders of Brandywine Realty Trust are incorporated by reference into Part III of this Form 10-K.
Entity Central Index Key	0000790816
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Document Information [Line Items]
Entity Registrant Name	Brandywine Operating Partnership, L.P.
Entity Incorporation, State or Country Code	DE
Entity File Number	000-24407
Entity Tax Identification Number	23-2862640
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Central Index Key	0001060386