v3.26.1
Bank Loans and Related Allowance for Credit Losses - Composition of Bank Loans and Delinquency Analysis by Loan Segment (Details) - USD ($)
Mar. 31, 2026
Dec. 31, 2025
Mar. 31, 2025
Dec. 31, 2024
Financing Receivable, Past Due [Line Items]        
Total loans $ 60,908,000,000 $ 57,991,000,000    
Allowance for credit losses 36,000,000 36,000,000 $ 21,000,000 $ 21,000,000
Total bank loans — net 60,872,000,000 57,955,000,000    
Loans accruing interest contractually 90 days or more past due 0 0    
Current        
Financing Receivable, Past Due [Line Items]        
Total loans 60,816,000,000 57,899,000,000    
Total past due and other nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans 92,000,000 92,000,000    
30-59 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 56,000,000 34,000,000    
60-89 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 4,000,000 15,000,000    
More than or equal to 90 days past
due and other
nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans 32,000,000 43,000,000    
Residential real estate        
Financing Receivable, Past Due [Line Items]        
Total loans 31,691,000,000 30,911,000,000    
Allowance for credit losses 30,000,000 29,000,000 15,000,000 15,000,000
Total bank loans — net 31,661,000,000 30,882,000,000    
Unamortized premiums and discounts and direct origination costs $ 136,000,000 $ 131,000,000    
Residential real estate | Loans Geographic Area | California | Geographic Concentration Risk        
Financing Receivable, Past Due [Line Items]        
Concentration (percent) 41.00% 41.00%    
Residential real estate | Current        
Financing Receivable, Past Due [Line Items]        
Total loans $ 31,656,000,000 $ 30,852,000,000    
Residential real estate | Total past due and other nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans 35,000,000 59,000,000    
Residential real estate | 30-59 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 11,000,000 14,000,000    
Residential real estate | 60-89 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 0 5,000,000    
Residential real estate | More than or equal to 90 days past
due and other
nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans 24,000,000 40,000,000    
Residential real estate | First Mortgages        
Financing Receivable, Past Due [Line Items]        
Total loans 31,269,000,000 30,484,000,000    
Allowance for credit losses 29,000,000 28,000,000 14,000,000 14,000,000
Total bank loans — net 31,240,000,000 30,456,000,000    
Residential real estate | First Mortgages | Current        
Financing Receivable, Past Due [Line Items]        
Total loans 31,237,000,000 30,429,000,000    
Residential real estate | First Mortgages | Total past due and other nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans 32,000,000 55,000,000    
Residential real estate | First Mortgages | 30-59 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 11,000,000 13,000,000    
Residential real estate | First Mortgages | 60-89 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 0 5,000,000    
Residential real estate | First Mortgages | More than or equal to 90 days past
due and other
nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans 21,000,000 37,000,000    
Residential real estate | HELOCs        
Financing Receivable, Past Due [Line Items]        
Total loans 422,000,000 427,000,000    
Allowance for credit losses 1,000,000 1,000,000 1,000,000 1,000,000
Total bank loans — net 421,000,000 426,000,000    
Residential real estate | HELOCs | Current        
Financing Receivable, Past Due [Line Items]        
Total loans 419,000,000 423,000,000    
Residential real estate | HELOCs | Total past due and other nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans 3,000,000 4,000,000    
Residential real estate | HELOCs | 30-59 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 0 1,000,000    
Residential real estate | HELOCs | 60-89 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 0 0    
Residential real estate | HELOCs | More than or equal to 90 days past
due and other
nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans 3,000,000 3,000,000    
Pledged asset lines        
Financing Receivable, Past Due [Line Items]        
Total loans 28,790,000,000 26,603,000,000    
Allowance for credit losses 0 0 0 0
Total bank loans — net 28,790,000,000 26,603,000,000    
Pledged asset lines | Current        
Financing Receivable, Past Due [Line Items]        
Total loans 28,733,000,000 26,570,000,000    
Pledged asset lines | Total past due and other nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans 57,000,000 33,000,000    
Pledged asset lines | 30-59 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 45,000,000 20,000,000    
Pledged asset lines | 60-89 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 4,000,000 10,000,000    
Pledged asset lines | More than or equal to 90 days past
due and other
nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans 8,000,000 3,000,000    
Other        
Financing Receivable, Past Due [Line Items]        
Total loans 427,000,000 477,000,000    
Allowance for credit losses 6,000,000 7,000,000 $ 6,000,000 $ 6,000,000
Total bank loans — net 421,000,000 470,000,000    
Other | Current        
Financing Receivable, Past Due [Line Items]        
Total loans 427,000,000 477,000,000    
Other | Total past due and other nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans 0 0    
Other | 30-59 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 0 0    
Other | 60-89 days past due        
Financing Receivable, Past Due [Line Items]        
Total loans 0 0    
Other | More than or equal to 90 days past
due and other
nonaccrual loans        
Financing Receivable, Past Due [Line Items]        
Total loans $ 0 $ 0