GOODWILL AND INTANGIBLE ASSETS - Other Intangibles (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Gross	$ 271	$ 97
Accumulated Amortization	74	33
Net	$ 197	64
Core deposits
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	10 years
Gross	$ 144	0
Accumulated Amortization	20	0
Net	124	0
Core deposits | Investors Acquisition
Finite-Lived Intangible Assets [Line Items]
Gross	97
Core deposits | Online Deposit Business And 80 East Coast Branches Of HSBC Bank
Finite-Lived Intangible Assets [Line Items]
Gross	47
Acquired technology
Finite-Lived Intangible Assets [Line Items]
Gross	23	21
Accumulated Amortization	19	11
Net	4	10
Acquired relationships
Finite-Lived Intangible Assets [Line Items]
Gross	54	53
Accumulated Amortization	21	14
Net	33	39
Naming Rights
Finite-Lived Intangible Assets [Line Items]
Gross	33	10
Accumulated Amortization	7	3
Net	26	7
Naming Rights | Investors Acquisition
Finite-Lived Intangible Assets [Line Items]
Gross	24
Other
Finite-Lived Intangible Assets [Line Items]
Gross	17	13
Accumulated Amortization	7	5
Net	$ 10	$ 8
Minimum | Acquired technology
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	5 years
Minimum | Acquired relationships
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	2 years
Minimum | Naming Rights
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	5 years
Minimum | Other
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	2 years
Maximum | Acquired technology
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	7 years
Maximum | Acquired relationships
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	15 years
Maximum | Naming Rights
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	10 years
Maximum | Other
Finite-Lived Intangible Assets [Line Items]
Amortizable Lives	7 years