v3.26.1
MORTGAGE LOAN SALES AND SERVICING RIGHTS - Residential Mortgage Portfolio, MSRs Fair Value Method Key Assumptions (Details) - Fair value method - Residential mortgage - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Mar. 31, 2026
Dec. 31, 2025
Servicing Assets at Fair Value [Line Items]    
Constant prepayment rate (annualized), actual 8.14% 8.09%
Constant prepayment rate (annualized), 10% adverse change $ (21) $ (17)
Constant prepayment rate (annualized), 20% adverse change $ (40) $ (33)
Spread over forward interest rate swap rates, actual 5.44% 5.38%
Spread over forward interest rate swap rates, 10% adverse change $ (17) $ (14)
Spread over forward interest rate swap rates, 20% adverse change $ (34) $ (27)