DERIVATIVE FINANCIAL INSTRUMENTS - Schedule of Derivative Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2026	Dec. 31, 2025
Asset Fair Value
Asset Fair Value	$ 717	$ 534
Liability Fair Value
Liability Fair Value	(807)	(494)
Qualifying Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	14,000	4,000
Asset Fair Value
Asset Fair Value	0	0
Liability Fair Value
Liability Fair Value	(1)	0
Qualifying Hedges \| Interest rate contracts \| Fair Value Hedges \| Long-term borrowings
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	3,500	0
Asset Fair Value
Asset Fair Value	0	0
Liability Fair Value
Liability Fair Value	(1)	0
Qualifying Hedges \| Interest rate contracts \| Cash Flow Hedges \| Loans
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	10,500	4,000
Asset Fair Value
Asset Fair Value	0	0
Liability Fair Value
Liability Fair Value	0	0
Non-qualifying Hedges
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	43,259	39,138
Asset Fair Value
Asset Fair Value	717	534
Liability Fair Value
Liability Fair Value	(806)	(494)
Non-qualifying Hedges \| Interest rate contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	32,436	28,741
Asset Fair Value
Asset Fair Value	555	385
Liability Fair Value
Liability Fair Value	(720)	(381)
Non-qualifying Hedges \| Foreign exchange contract
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	9,141	8,912
Asset Fair Value
Asset Fair Value	115	122
Liability Fair Value
Liability Fair Value	(84)	(113)
Non-qualifying Hedges \| Foreign exchange spot contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	510	252
Liability Fair Value
Net fair value	1	0
Non-qualifying Hedges \| Equity warrants
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	69	69
Asset Fair Value
Asset Fair Value	44	27
Liability Fair Value
Liability Fair Value	0	0
Non-qualifying Hedges \| Other contracts
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	1,613	1,416
Asset Fair Value
Asset Fair Value	3	0
Liability Fair Value
Liability Fair Value	$ (2)	$ 0

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Nominal or face amount used to calculate payment on derivative.

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