v3.26.3
MORTGAGE SERVICING RIGHTS - Fair Value Disclosures (Detail) - MSRs - USD ($)
$ in Millions
9 Months Ended
Sep. 30, 2026
Dec. 31, 2025
MORTGAGE SERVICING RIGHTS    
Fair value of the MSRs $ 1,400.0 $ 1,400.0
Sensitivity Analysis of Fair Value, example 1, impact of percent adverse change in discount rate, percent 1.00%  
Decrease in fair value as a result of 100 basis point increase in discount rate $ 38.8  
Sensitivity Analysis of Fair Value, example 2, impact of percent adverse change in discount rate, percent 2.00%  
Decrease in fair value as a result of 200 basis point increase in discount rate $ 74.9  
Sensitivity Analysis of Fair Value, example 1, impact of percent adverse change in placement fee rate, percent 0.50%  
Decrease in fair value as a result of 50 basis point decrease in placement fee rate $ 50.7  
Sensitivity Analysis of Fair Value, example 2, impact of percent adverse change in placement fee rate, percent 1.00%  
Decrease in fair value as a result of 100 basis point decrease in placement fee rate $ 101.4