v3.26.3
MORTGAGE LOAN SALES AND SERVICING RIGHTS - Residential Mortgage Portfolio, MSRs Fair Value Method Key Assumptions (Details) - Fair value method - Residential mortgage - USD ($)
$ in Millions
9 Months Ended 12 Months Ended
Sep. 30, 2026
Dec. 31, 2025
Servicing Assets at Fair Value [Line Items]    
Constant prepayment rate (annualized), actual 6.61% 8.09%
Constant prepayment rate (annualized), 10% adverse change $ (19) $ (17)
Constant prepayment rate (annualized), 20% adverse change $ (37) $ (33)
Spread over forward interest rate swap rates, actual 5.43% 5.38%
Spread over forward interest rate swap rates, 10% adverse change $ (19) $ (14)
Spread over forward interest rate swap rates, 20% adverse change $ (38) $ (27)