Loan and Lease Receivables, Impaired Loans and Leases and Allowance for Loan and Lease Losses (Policies)	9 Months Ended
Sep. 30, 2021
Receivables [Abstract]
Loans and Leases Receivable, Allowance for Loan Losses	To determine the level and composition of the allowance for loan and lease losses, the Corporation categorizes the portfolio into segments with similar risk characteristics. First, the Corporation evaluates loans and leases for potential impairment classification. The Corporation analyzes each loan and lease determined to be impaired on an individual basis to determine a specific reserve based upon the estimated value of the underlying collateral for collateral-dependent loans, or alternatively, the present value of expected cash flows. The Corporation applies historical trends from established risk factors to each category of loans and leases that has not been individually evaluated for the purpose of establishing the general portion of the allowance.

Disclosure of accounting policy for estimating the allowance for losses on loans and lease receivables. The disclosure may include (a) how the entity determines each element of the allowance, (b) which loans are evaluated individually and which loans are evaluated as a group, (c) how the entity determines both the allocated and unallocated portions of the allowance, (d) how the entity determines the loss factors applied to graded loans in order to develop a general allowance, and (e) what self-correcting mechanism the entity uses to reduce differences between estimated and actual losses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5144-111524

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