LOANS - Corporate Troubled Debt Restructurings (Details) - Corporate $ in Millions	3 Months Ended
	Mar. 31, 2022 USD ($)
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	$ 12
Commercial and industrial
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	12
Mortgage and real estate
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0
Other
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0
TDRs involving changes in the amount and/or timing of principal payments
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0
TDRs involving changes in the amount and/or timing of principal payments | Commercial and industrial
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0
TDRs involving changes in the amount and/or timing of principal payments | Mortgage and real estate
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0
TDRs involving changes in the amount and/or timing of principal payments | Other
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0
TDRs involving vhanges in the amount and/or timing of interest payments
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0
TDRs involving vhanges in the amount and/or timing of interest payments | Commercial and industrial
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0
TDRs involving vhanges in the amount and/or timing of interest payments | Mortgage and real estate
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0
TDRs involving vhanges in the amount and/or timing of interest payments | Other
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0
TDRs invovling changes in the amount and/or timing of both principal and interest payments
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	12
TDRs invovling changes in the amount and/or timing of both principal and interest payments | Commercial and industrial
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	12
TDRs invovling changes in the amount and/or timing of both principal and interest payments | Mortgage and real estate
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0
TDRs invovling changes in the amount and/or timing of both principal and interest payments | Other
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	$ 0