FAIR VALUE MEASUREMENTS - Residential Mortgage and Commercial Real Estate Loans Held For Sale (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Aggregate Fair Value	$ 505	$ 676
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Aggregate Fair Value	505	676
Level 2 \| Residential mortgage loans held for sale, at fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Aggregate Fair Value	437	614
Aggregate Unpaid Principal	427	593
Aggregate Fair Value Greater (Less) Than Aggregate Unpaid Principal	10	21
Level 2 \| Commercial and industrial, and commercial real estate loans held for sale, at fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Aggregate Fair Value	68	62
Aggregate Unpaid Principal	74	69
Aggregate Fair Value Greater (Less) Than Aggregate Unpaid Principal	$ (6)	$ (7)

The aggregate unpaid principal balance of loans measured at fair value.

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

No definition available.

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- Definition

This item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of loans and long-term receivables (other than securities categorized as trading, available-for-sale or held-to-maturity) that have contractual principal amounts and for which the fair value option has been elected.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482907/825-10-50-28

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- Definition

Amount, before valuation allowance, of financing receivable classified as held-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481990/310-10-45-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481852/948-310-45-1

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