v3.25.2
Commitments and Contingent Liabilities (Narrative) (Details)
 1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended 90 Months Ended
Mar. 05, 2024
EUR (€)
May 31, 2024
exchange_offer
shares
Jun. 30, 2024
USD ($)
Jun. 30, 2024
USD ($)
Dec. 31, 2023
USD ($)
Dec. 31, 2015
trust
Jun. 30, 2025
USD ($)
$ / shares
shares
Dec. 31, 2024
USD ($)
Loss Contingencies [Line Items]                
Minimum securities lending related collateral percentage             100.00%  
Commitments and letters of credit             $ 312,295,600,000 $ 285,453,400,000
Repurchase agreement counterparty, amount at risk             0 0
Loss contingency accrual             $ 0  
Common stock, convertible, conversion price             1.5342  
Securities Lent with Indemnification                
Loss Contingencies [Line Items]                
Commitments and letters of credit             $ 169,168,800,000 144,543,700,000
Indemnification Agreement                
Loss Contingencies [Line Items]                
Credit loss liability             0 $ 0
FDIC Special Assessment                
Loss Contingencies [Line Items]                
Loss contingency accrual         $ 84,600,000      
Additional cost     $ 2,300,000 $ 14,700,000 $ 84,600,000      
Northern Trust Fiduciary Services (Guernsey) Limited                
Loss Contingencies [Line Items]                
Litigation settlement, amount awarded to other party | € € 187,500              
Visa                
Loss Contingencies [Line Items]                
Escrow deposit             4,600,000,000  
Visa Class B-2 Shares                
Loss Contingencies [Line Items]                
Exchange offer program, shares received upon expiration (in shares) | shares   2,100,000            
Carryover basis             0  
Estimated value assuming conversion             $ 1,100,000,000  
Visa Class C shares                
Loss Contingencies [Line Items]                
Exchange offer program, shares received upon expiration (in shares) | shares   819,500            
Exchange offer program, number of exchange offers | exchange_offer   3            
Exchange offer program, length of time between exchanges   12 months            
Exchange offer program, claim reduction percentage   50.00%            
Number of shares held (in shares) | shares             15,300  
Equity securities             $ 21,700,000  
Visa Class A | Visa                
Loss Contingencies [Line Items]                
Share price (in USD) | $ / shares             $ 355.05  
Northern Trust Fiduciary Services (Guernsey) Limited | Subsidiaries                
Loss Contingencies [Line Items]                
Number of administrated trusts serving as trustee on | trust           2    
Lower Limit                
Loss Contingencies [Line Items]                
Estimated loss             $ 0  
Upper Limit                
Loss Contingencies [Line Items]                
Estimated loss             $ 25,000,000