Capital Ratios (Schedule Of The Total Risk-based, Tier 1 Risk-based And Tier 1 Leverage Requirements) (Details)	Mar. 31, 2022	Dec. 31, 2021
Franklin Financial Services Corporation [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 Risk-based Capital Ratio: Ratio	0.1494	0.1520
Tier 1 Risk-based Capital Ratio: Ratio	0.1494	0.1520
Total Risk-based Capital Ratio: Ratio	0.1809	0.1841
Tier 1 Leverage Ratio: Ratio	0.0859	0.0852
Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 Risk-based Capital Ratio: Ratio	0.1505	0.1528
Common Equity Tier 1 Risk-based Capital Ratio: Adequately Capitalized Minimum: Ratio	0.0450
Common Equity Tier 1 Risk-based Capital Ratio: Well Capitalized Minimum: Ratio	0.065
Tier 1 Risk-based Capital Ratio: Ratio	0.1505	0.1528
Tier 1 Risk-based Capital Ratio: Adequately Capitalized Minimum: Ratio	0.0600
Tier 1 Risk-based Capital Ratio: Well Capitalized Minimum: Ratio	0.08
Total Risk-based Capital Ratio: Ratio	0.1630	0.1654
Total Risk-based Capital Ratio: Adequately Capitalized Minimum: Ratio	0.0800
Total Risk-based Capital Ratio: Well Capitalized Minimum: Ratio	0.10
Tier 1 Leverage Ratio: Ratio	0.0865	0.0857
Tier 1 Leverage Ratio: Adequately Capitalized Minimum: Ratio	0.0400
Tier 1 Leverage Ratio: Well Capitalized Minimum: Ratio	0.05

Tangible Capital Required For Well Capitalized To Tangible Assets

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Ratio of minimum total risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
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Ratio of minimum tangible capital to tangible assets required for capital adequacy as defined by regulatory framework.

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