Capital Ratios (Schedule Of The Total Risk-based, Tier 1 Risk-based And Tier 1 Leverage Requirements) (Details)	Sep. 30, 2023	Dec. 31, 2022
Franklin Financial Services Corporation [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 Risk-based Capital Ratio: Ratio	0.1243	0.1422
Tier 1 Risk-based Capital Ratio: Ratio	0.1243	0.1422
Total Risk-based Capital Ratio: Ratio	0.1516	0.1721
Tier 1 Leverage Ratio: Ratio	0.0910	0.0895
Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common Equity Tier 1 Risk-based Capital Ratio: Ratio	0.1303	0.1463
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	0.1303	0.1463
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	0.1428	0.1588
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	0.0953	0.0921
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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Ratio of minimum total risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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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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