LOANS AND LEASES - Schedule of Loans Charge-offs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 177	$ 199	$ 464	$ 437
Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			9	43
Year two			79	119
Year three			134	63
Year four			48	67
Year five			28	53
Prior year			96	26
Revolving			69	65
Revolving Converted to Term Loans			1	1
Total			464	437
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	116	83	287	207
Commercial | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			9	6
Year two			37	60
Year three			69	26
Year four			19	10
Year five			25	53
Prior year			89	24
Revolving			38	27
Revolving Converted to Term Loans			1	1
Total			287	207
Commercial | Owner occupied commercial mortgage | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			0	0
Year two			0	0
Year three			0	0
Year four			0	0
Year five			0	0
Prior year			8	0
Revolving			0	1
Revolving Converted to Term Loans			0	0
Total			8	1
Commercial | Non-owner occupied commercial mortgage | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			0	0
Year two			0	0
Year three			0	0
Year four			0	0
Year five			19	48
Prior year			70	12
Revolving			0	0
Revolving Converted to Term Loans			0	0
Total			89	60
Commercial | Commercial and industrial | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			8	5
Year two			33	53
Year three			65	22
Year four			15	7
Year five			4	4
Prior year			9	11
Revolving			38	26
Revolving Converted to Term Loans			1	1
Total			173	129
Commercial | Leases | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			1	1
Year two			4	7
Year three			4	4
Year four			4	3
Year five			2	1
Prior year			2	1
Revolving			0	0
Revolving Converted to Term Loans			0	0
Total			17	17
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	8	7	21	21
Consumer | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			0	5
Year two			3	2
Year three			2	2
Year four			2	1
Year five			0	0
Prior year			2	2
Revolving			12	9
Revolving Converted to Term Loans			0	0
Total			21	21
Consumer | Residential mortgage | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			0	0
Year two			0	0
Year three			0	0
Year four			0	0
Year five			0	0
Prior year			1	2
Revolving			0	0
Revolving Converted to Term Loans			0	0
Total			1	2
Consumer | Consumer auto | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			0	0
Year two			2	1
Year three			1	1
Year four			1	1
Year five			0	0
Prior year			0	0
Revolving			0	0
Revolving Converted to Term Loans			0	0
Total			4	3
Consumer | Consumer other | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			0	5
Year two			1	1
Year three			1	1
Year four			1	0
Year five			0	0
Prior year			1	0
Revolving			12	9
Revolving Converted to Term Loans			0	0
Total			16	16
SVB
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 53	$ 109	156	209
SVB | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			0	32
Year two			39	57
Year three			63	35
Year four			27	56
Year five			3	0
Prior year			5	0
Revolving			19	29
Revolving Converted to Term Loans			0	0
Total			156	209
SVB | Investor dependent - early stage | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			0	1
Year two			28	17
Year three			40	18
Year four			18	3
Year five			2	0
Prior year			0	0
Revolving			6	10
Revolving Converted to Term Loans			0	0
Total			94	49
SVB | Investor dependent - growth stage | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			0	24
Year two			9	40
Year three			23	17
Year four			9	13
Year five			1	0
Prior year			4	0
Revolving			1	1
Revolving Converted to Term Loans			0	0
Total			47	95
SVB | Innovation C&I and cash flow dependent | Amount of Principal Forgiven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Year one			0	7
Year two			2	0
Year three			0	0
Year four			0	40
Year five			0	0
Prior year			1	0
Revolving			12	18
Revolving Converted to Term Loans			0	0
Total			$ 15	$ 65