Cover Page - shares	6 Months Ended
	Jun. 30, 2025	Jul. 31, 2025
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2025
Document Transition Report	false
Entity File Number	001-37722
Entity Registrant Name	SPYRE THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-4312787
Entity Address, Address Line One	221 Crescent Street
Entity Address, Address Line Two	Building 23
Entity Address, Address Line Three	Suite 105
Entity Address, City or Town	Waltham
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02453
City Area Code	617
Local Phone Number	651-5940
Title of 12(b) Security	Common Stock, $0.0001 Par Value Per Share
Trading Symbol	SYRE
Security Exchange Name	NASDAQ
Entity Interactive Data Current	Yes
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		60,400,960
Entity Central Index Key	0001636282
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	Q2