XML 109 R91.htm IDEA: XBRL DOCUMENT v3.21.2
NONINTEREST INCOME - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Trust and investment services fees        
Disaggregation of Revenue [Line Items]        
Trailing commission income $ 4 $ 3 $ 12 $ 10