Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2022	Feb. 28, 2023	Jun. 30, 2022
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Annual Report	true
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2022
Document Period End Date	Dec. 31, 2022
Document Transition Report	false
Entity File Number	001-38884
Entity Registrant Name	FRANKLIN FINANCIAL SERVICES CORPORATION
Entity Incorporation, State or Country Code	PA
Entity Tax Identification Number	25-1440803
Entity Address, Address Line One	1500 Nitterhouse Drive
Entity Address, City or Town	Chambersburg
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	17201-0819
City Area Code	717
Local Phone Number	264-6116
Title of 12(b) Security	Common stock
Trading Symbol	FRAF
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation	false
Entity Public Float			$ 120,401,826
Entity Common Stock, Shares Outstanding		4,398,823
Documents Incorporated by Reference	Portions of the definitive annual proxy statement to be filed, pursuant to Reg. 14A within 120 days after December 31, 2022, are incorporated into Part III.
Entity Central Index Key	0000723646
Auditor Name	Crowe LLP
Auditor Location	Cleveland, Ohio
Auditor Firm ID	173