Significant Accounting Policies - Narrative (Details) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($)
Change in Accounting Estimate [Line Items]
Performance obligation, description of timing	one year or less
Deposit Bases
Change in Accounting Estimate [Line Items]
Intangible assets, amortization period	10 years
Minimum \| Furniture and Fixtures
Change in Accounting Estimate [Line Items]
Useful life of premises and equipment	3 years
Minimum \| Building
Change in Accounting Estimate [Line Items]
Useful life of premises and equipment	7 years
Maximum \| Furniture and Fixtures
Change in Accounting Estimate [Line Items]
Useful life of premises and equipment	15 years
Maximum \| Building
Change in Accounting Estimate [Line Items]
Useful life of premises and equipment	45 years
Non-Accruing
Change in Accounting Estimate [Line Items]
Accounts receivable, net	$ 10

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(5))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

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+ References

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

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