LOANS - Corporate Loan Modifications to Borrowers Experiencing Financial Difficulty (Details) - Corporate loans - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 19	$ 115
Commitments to lend	51	530
Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	19	115
Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0
Commercial and industrial
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 19	$ 61
Weighted average term extension	22 months	12 months
Commercial and industrial | Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 19	$ 61
Commercial and industrial | Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	0	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	$ 54
Weighted average term extension		18 months
Mortgage and real estate | Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	0	$ 54
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	0	0
Other | Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0
Other | Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 0	$ 0