v3.26.1
Investment Securities (Fair Value of Securities Pledged and Accepted as Collateral) (Details) - USD ($)
$ in Millions
Mar. 31, 2026
Dec. 31, 2025
Summary of Investment Holdings [Line Items]    
Permitted by contract or custom to sell or repledge $ 1,227 $ 759
Permitted amount repledged to others 1,227 759
Asset Pledged as Collateral    
Summary of Investment Holdings [Line Items]    
Debt securities, pledged to others $ 59,718 $ 61,230