v3.26.1
Bank Loans and Related Allowance for Credit Losses - Changes in Allowance for Credit Losses (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Financing Receivable, Allowance for Credit Loss [Roll Forward]          
Beginning balance $ 36 $ 21 $ 36 $ 21 $ 21
Charge-offs 0 0 0 0  
Recoveries 0 0 0 0  
Provision for credit losses 1 1 1 1  
Ending balance 37 22 37 22 36
Total residential real estate          
Financing Receivable, Allowance for Credit Loss [Roll Forward]          
Beginning balance 30 15 29 15 15
Charge-offs 0 0 0 0  
Recoveries 0 0 0 0  
Provision for credit losses 1 1 2 1  
Ending balance 31 16 31 16 29
Total residential real estate | First Mortgages          
Financing Receivable, Allowance for Credit Loss [Roll Forward]          
Beginning balance 29 14 28 14 14
Charge-offs 0 0 0 0 0
Recoveries 0 0 0 0  
Provision for credit losses 1 1 2 1  
Ending balance 30 15 30 15 28
Total residential real estate | HELOCs          
Financing Receivable, Allowance for Credit Loss [Roll Forward]          
Beginning balance 1 1 1 1 1
Charge-offs 0 0 0 0 0
Recoveries 0 0 0 0  
Provision for credit losses 0 0 0 0  
Ending balance 1 1 1 1 1
Pledged asset lines          
Financing Receivable, Allowance for Credit Loss [Roll Forward]          
Beginning balance 0 0 0 0 0
Charge-offs 0 0 0 0  
Recoveries 0 0 0 0  
Provision for credit losses 0 0 0 0  
Ending balance 0 0 0 0 0
Other          
Financing Receivable, Allowance for Credit Loss [Roll Forward]          
Beginning balance 6 6 7 6 6
Charge-offs 0 0 0 0  
Recoveries 0 0 0 0  
Provision for credit losses 0 0 (1) 0  
Ending balance $ 6 $ 6 $ 6 $ 6 $ 7