LOANS - Corporate Loan Modifications to Borrowers Experiencing Financial Difficulty (Details) - Corporate loans - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 76	$ 53	$ 141	$ 237
Commitments to lend	105	924	105	924
Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	76	53	141	237
Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0	0	0
Commercial and industrial
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 76	$ 4	$ 141	$ 107
Weighted average term extension	12 months	6 months	10 months	11 months
Commercial and industrial | Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 76	$ 4	$ 141	$ 107
Commercial and industrial | Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0	0	0
Financial institutions
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0	0	0
Financial institutions | Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0	0	0
Financial institutions | Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0	0	0
Mortgage and real estate
Financing Receivable, Modified [Line Items]
Total modifications balance	0	$ 49	0	$ 130
Weighted average term extension		6 months		7 months
Mortgage and real estate | Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	0	$ 49	0	$ 130
Mortgage and real estate | Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0	0	0
Other
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0	0	0
Other | Term extension
Financing Receivable, Modified [Line Items]
Total modifications balance	0	0	0	0
Other | Combination: term extension and payment delay
Financing Receivable, Modified [Line Items]
Total modifications balance	$ 0	$ 0	$ 0	$ 0