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LOAN SERVICING - Schedule of Sensitivity of Fair Value to Changes in Key Assumptions (Details) - Mortgage Servicing Rights - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2025	Dec. 31, 2024
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Weighted average life (months)	90 months	96 months
Constant prepayment rate (annualized)	8.60%	7.60%
Discount rate	10.10%	10.30%
Sensitivity analysis of fair value, change in interest rates, plus 2.00%	$ 13	$ 6
Sensitivity analysis of fair value, change in interest rates, plus 1.00%	10	5
Sensitivity analysis of fair value, change in interest rates, plus 0.50%	7	3
Sensitivity analysis of fair value, change in interest rates, plus 0.25%	4	2
Sensitivity analysis of fair value, change in interest rates, minus 0.25%	(4)	(2)
Sensitivity analysis of fair value, change in interest rates, minus 0.50%	(7)	(5)
Sensitivity analysis of fair value, change in interest rates, minus 1.00%	(13)	(11)
Sensitivity analysis of fair value, change in interest rates, minus 2.00%	(23)	(20)
Sensitivity analysis of fair value, change in interest rates, minus 3.00%	$ (41)	$ (34)

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- Definition

Assumption for fair value on securitization date of interests continued to be held by transferor servicing assets or liabilities annualized constant prepayment rate.

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No definition available.

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Sensitivity Analysis Of Fair Value Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities Impact Of One Point Zero Percent Adverse Change In Prepayment Speed

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No definition available.

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Sensitivity analysis of fair value of interests continued to be held by transferor servicing assets or liabilities impact of one point zero percent favorable change in prepayment speed.

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No definition available.

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Sensitivity Analysis Of Fair Value Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities Impact Of Three Point Zero Percent Adverse Change In Prepayment Speed

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- Definition

Sensitivity Analysis Of Fair Value Of Interests Continued To Be Held By Transferor Servicing Assets Or Liabilities Impact Of Two Point Zero Percent Adverse Change In Prepayment Speed

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No definition available.

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Sensitivity analysis of fair value of interests continued to be held by transferor servicing assets or liabilities impact of zero point five zero percent adverse change in prepayment speed.

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No definition available.

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Sensitivity analysis of fair value of interests continued to be held by transferor servicing assets or liabilities impact of zero point two five percent adverse change in prepayment speed.

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No definition available.

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Sensitivity analysis of fair value of interests continued to be held by transferor servicing assets or liabilities impact of zero point two five percent favorable change in prepayment speed.

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No definition available.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481326/860-20-50-4

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- Definition

Discount rate which is used to value residual cash flows generated by financial assets of the securitization, asset-backed financing arrangement, or similar transfer for initial fair value measurement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481326/860-20-50-3

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- Definition

Weighted average life of securitized assets for initial fair value measurement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481326/860-20-50-3

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