LOANS - Corporate Loan Modifications to Borrowers Experiencing Financial Difficulty (Details) - Corporate loans - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2026	Mar. 31, 2025
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 140	$ 19
Commitments to lend	521	51
Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	135	19
Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	5	0
Commercial and industrial
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 124	$ 19
Weighted average term extension	13 months	22 months
Commercial and industrial \| Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 119	$ 19
Commercial and industrial \| Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	5	0
Financial institutions
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0
Financial institutions \| Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0
Financial institutions \| Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0
Mortgage and real estate
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0
Mortgage and real estate \| Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0
Mortgage and real estate \| Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0
Other
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 16	0
Weighted average term extension	46 months
Other \| Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 16	0
Other \| Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 0	$ 0

Amortized cost excluding accrued interest, of financing receivable modified during period for debtor experiencing financial difficulty.

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