SECURITIES - Schedule of Securities Pledged (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Pledged against derivatives, to qualify for fiduciary powers, or to secure public and other deposits as required by law
Financial Instruments Owned and Pledged as Collateral [Line Items]
Debt securities at amortized cost	$ 3,975	$ 5,619
Debt securities at fair value	3,644	5,305
Pledged as collateral for FHLB borrowing capacity
Financial Instruments Owned and Pledged as Collateral [Line Items]
Debt securities at amortized cost	237	242
Debt securities at fair value	224	220
Pledged against repurchase agreements
Financial Instruments Owned and Pledged as Collateral [Line Items]
Debt securities at amortized cost	0	0
Debt securities at fair value	$ 0	$ 0

Amount, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), investment in debt security measured at amortized cost (held-to-maturity), and investment in debt security measured at fair value with change in fair value recognized in net income (trading).

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 944
-SubTopic 80
-Name Accounting Standards Codification
-Section 55
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480078/944-80-55-14

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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity) and investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 320
-SubTopic 10
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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 946
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-Name Accounting Standards Codification
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- Details

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