BORROWINGS AND LONG-TERM DEBT - Narrative (Details) - USD ($)	Jun. 30, 2026	Dec. 31, 2025
Debt Instrument [Line Items]
Outstanding FHLB advances	$ 0	$ 0
Investment in stock of FHLB	17,300,000	17,300,000
Borrowings	80,000,000	0
Federal Reserve Bank Discount Window
Debt Instrument [Line Items]
Federal reserve bank, advances, general debt obligations, additional borrowing capacity	4,400,000,000
Borrowings	80,000,000	0
Brokered and Wholesale Debt
Debt Instrument [Line Items]
Borrowings	0	$ 0
Line of credit facility, remaining borrowing capacity	5,000,000,000.0
Asset Pledged as Collateral \| Financing Receivable, Consumer Loans, Borrower-In-Custody Program \| Federal Reserve Bank Discount Window
Debt Instrument [Line Items]
Federal reserve bank, advances, general debt obligations, disclosures, collateral pledged	1,200,000,000
Asset Pledged as Collateral \| Investment Securities, Federal Reserve Discount Window Program \| Federal Reserve Bank Discount Window
Debt Instrument [Line Items]
Federal reserve bank, advances, general debt obligations, disclosures, collateral pledged	3,500,000,000
Federal Home Loan Bank of San Francisco
Debt Instrument [Line Items]
Loans receivable pledged against FHLB	10,200,000,000
Additional borrowing capacity	$ 5,900,000,000

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