LOANS AND LEASES - Schedule of Financial Effects of Loans Modified (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	21 months	5 months
Weighted Average Interest Rate Reduction	1.52%	1.31%
Weighted Average Payment Delay (in Months)	22 months	8 months
Amount of Principal Forgiven	$ 0	$ 0
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	21 months	5 months
Weighted Average Interest Rate Reduction	1.31%	1.29%
Weighted Average Payment Delay (in Months)	41 months	8 months
Amount of Principal Forgiven	$ 0	$ 0
Commercial | Commercial construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	22 months	9 months
Weighted Average Interest Rate Reduction	2.49%	0.00%
Weighted Average Payment Delay (in Months)	0 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
Commercial | Owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	23 months	12 months
Weighted Average Interest Rate Reduction	0.79%	3.85%
Weighted Average Payment Delay (in Months)	20 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
Commercial | Non-owner occupied commercial mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	27 months	3 months
Weighted Average Interest Rate Reduction	0.00%	0.00%
Weighted Average Payment Delay (in Months)	48 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	9 months	6 months
Weighted Average Interest Rate Reduction	1.39%	1.17%
Weighted Average Payment Delay (in Months)	4 months	8 months
Amount of Principal Forgiven	$ 0	$ 0
Commercial | Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	0 months	0 months
Weighted Average Interest Rate Reduction	0.00%	0.00%
Weighted Average Payment Delay (in Months)	0 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	53 months	31 months
Weighted Average Interest Rate Reduction	2.41%	2.51%
Weighted Average Payment Delay (in Months)	0 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
Consumer | Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	52 months	29 months
Weighted Average Interest Rate Reduction	1.52%	0.00%
Weighted Average Payment Delay (in Months)	0 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
Consumer | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	59 months	60 months
Weighted Average Interest Rate Reduction	4.15%	0.39%
Weighted Average Payment Delay (in Months)	0 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
Consumer | Consumer auto
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	30 months	0 months
Weighted Average Interest Rate Reduction	0.26%	0.00%
Weighted Average Payment Delay (in Months)	0 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
Consumer | Consumer other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	49 months	0 months
Weighted Average Interest Rate Reduction	9.19%	9.72%
Weighted Average Payment Delay (in Months)	0 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
SVB
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	14 months	6 months
Weighted Average Interest Rate Reduction	0.00%	0.00%
Weighted Average Payment Delay (in Months)	9 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
SVB | Global fund banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	0 months	0 months
Weighted Average Interest Rate Reduction	0.00%	0.00%
Weighted Average Payment Delay (in Months)	0 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
SVB | Investor dependent - early stage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	6 months	0 months
Weighted Average Interest Rate Reduction	0.00%	0.00%
Weighted Average Payment Delay (in Months)	7 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
SVB | Investor dependent - growth stage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	19 months	6 months
Weighted Average Interest Rate Reduction	0.00%	0.00%
Weighted Average Payment Delay (in Months)	10 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
SVB | Innovation C&I and cash flow dependent
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	12 months	0 months
Weighted Average Interest Rate Reduction	0.00%	0.00%
Weighted Average Payment Delay (in Months)	6 months	0 months
Amount of Principal Forgiven	$ 0	$ 0
SVB | Private Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	0 months	0 months
Weighted Average Payment Delay (in Months)	0 months	0 months
SVB | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	0 months	0 months
Weighted Average Payment Delay (in Months)	0 months	0 months
SVB | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Weighted Average Term Extension (in Months)	0 months	0 months
Weighted Average Payment Delay (in Months)	0 months	0 months