FAIR VALUES OF ASSETS AND LIABILITIES - Fair Value Option-Changes in Fair Value (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Loans held for sale
Fair Value, Option, Quantitative Disclosures [Line Items]
Net gains (losses) from fair value changes	$ (48)	$ 1	$ (44)	$ 16
Loans held for investment
Fair Value, Option, Quantitative Disclosures [Line Items]
Net gains (losses) from fair value changes	(1)	0	(1)	(1)
Long-term debt
Fair Value, Option, Quantitative Disclosures [Line Items]
Net gains (losses) from fair value changes	$ 13	$ 0	$ 31	$ (5)

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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