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Short-Term Borrowings (Details) - USD ($) $ in Millions | 9 Months Ended |
--- | --- | ---
Sep. 30, 2021 | Dec. 31, 2020
Short-Term Borrowings (Details) [Line Items] |  |
Purchases of federal funds | $ 41.0 | $ 41.0
Retail Repurchase Agreements [Member] |  |
Short-Term Borrowings (Details) [Line Items] |  |
Mortgage-backed securities maturity, basis of allocation description | These securities have various maturity dates from 2022 through 2051. |
Maximum amount of outstanding agreements at any month-end | $ 25.2 |
Short-term borrowings mature, description | The repurchase agreements mature within one month. |

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