Summary of Significant Accounting and Reporting Policies - Portfolio Loans and Leases (Details) $ in Millions	Dec. 31, 2020 USD ($)
Accounting Policies [Abstract]
Established threshold nonaccrual commercial loans	$ 1
Threshold period past due	180 days
Threshold period past due, charge off	120 days

Commercial loans on nonaccrual status, as well as criticized commercial loans with aggregate borrower relationships exceeding the threshold are subject to an individual review to identify charge-offs.

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

- References

No definition available.

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- Definition

Threshold period for when financing receivable is considered past due, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Excludes threshold period past due to write off as uncollectible.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919253-210447

+ Details

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- Definition

Threshold period for when financing receivable is considered past due to write off as uncollectible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919253-210447

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