LOANS - Corporate Troubled Debt Restructurings (Details) - Corporate - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2022
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	$ 26	$ 38
Commercial and industrial
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	3	15
Other
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	23	23
TDRs involving changes in the amount and/or timing of principal payments
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0	1
TDRs involving changes in the amount and/or timing of principal payments | Commercial and industrial
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0	0
TDRs involving changes in the amount and/or timing of principal payments | Other
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0	1
TDRs involving vhanges in the amount and/or timing of interest payments
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0	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	0
TDRs involving vhanges in the amount and/or timing of interest payments | Other
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	0	0
TDRs invovling changes in the amount and/or timing of both principal and interest payments
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	26	37
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	3	15
TDRs invovling changes in the amount and/or timing of both principal and interest payments | Other
Financing Receivable, Modified [Line Items]
Troubled debt restructurings	$ 23	$ 22