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Commitments and Contingencies (Narrative) (Details) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025 USD ($)	Sep. 30, 2024 entity	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($) entity	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Financial guarantees in connection with standby letters of credit			$ 0	$ 0
Standby letters of credit expiring within one year	$ 329		329
Standby letters of credit expiring thereafter	25		25
Loss Contingency Accrual	1		1
Concentration Risk [Line Items]
Loss Contingency Accrual	1		1
iCap Entities [Member]
Concentration Risk [Line Items]
Number of Defendant Entities | entity				34
Loss Contingency, Damages Sought, Value			290
iCap Trust [Member]
Concentration Risk [Line Items]
Loss Contingency, Damages Sought, Value	90
Loss Contingency, Number of Defendants | entity		488
Professional Financial Investors, Inc. and Professional Investors Security Fund, Inc. [Member]
Commitments and Contingencies Disclosure [Abstract]
Loss Contingency Accrual	55		55
Concentration Risk [Line Items]
Loss Contingency Accrual	$ 55		55
Minimum | Professional Financial Investors, Inc. and Professional Investors Security Fund, Inc. [Member]
Concentration Risk [Line Items]
Loss Contingency, Damages Sought, Value			297
Maximum | Professional Financial Investors, Inc. and Professional Investors Security Fund, Inc. [Member]
Concentration Risk [Line Items]
Loss Contingency, Damages Sought, Value			$ 368
Product Concentration Risk | Revenue Benchmark | Real Estate Loans As Part Of Loan Portfolio
Concentration Risk [Line Items]
Concentration risk (as a percent)			77.00%		75.00%
Product Concentration Risk | Revenue Benchmark | Multifamily Loans as Part of Loan portfolio [Member]
Concentration Risk [Line Items]
Concentration risk (as a percent)			24.00%		19.00%
Product Concentration Risk | Revenue Benchmark | Commercial Office Loans as Part of Loan portfolio [Member]
Concentration Risk [Line Items]
Concentration risk (as a percent)			8.00%		8.00%

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