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.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 275
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 275
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Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 275
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-URI https://asc.fasb.org/1943274/2147482861/275-10-50-18

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 275
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-Section 50
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-URI https://asc.fasb.org/1943274/2147482861/275-10-50-18

Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 275
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-Name Accounting Standards Codification
-Section 50
-Paragraph 18
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-Publisher FASB
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Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 275
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 275
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-URI https://asc.fasb.org/1943274/2147482861/275-10-50-20

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 954
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Commitments and Contingencies (Narrative) (Details) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2023 USD ($) entity	Mar. 31, 2026	Sep. 30, 2026 USD ($)	Sep. 30, 2025 USD ($)	Dec. 31, 2025
Commitments and Contingencies Disclosure [Abstract]
Financial guarantees in connection with standby letters of credit			$ 0	$ 0
Standby letters of credit expiring within one year			480
Standby letters of credit expiring thereafter			$ 15
iCap Entities [Member]
Concentration Risk [Line Items]
Number of defendant entities \| entity	34
Loss contingency, damages sought, value	$ 290
Product Concentration Risk \| Revenue Benchmark \| Real Estate Loans As Part Of Loan Portfolio
Concentration Risk [Line Items]
Concentration risk (as a percent)		76.00%	74.00%
Product Concentration Risk \| Revenue Benchmark \| Multifamily Loans as Part of Loan portfolio
Concentration Risk [Line Items]
Concentration risk (as a percent)		23.00%	23.00%		24.00%
Product Concentration Risk \| Revenue Benchmark \| Commercial Office Loans as Part of Loan portfolio
Concentration Risk [Line Items]
Concentration risk (as a percent)			7.00%		8.00%