DERIVATIVES - Schedule of Fair Value Hedges (Details) - Interest rate swap - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Interest And Dividend Income, Investment Securities
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	$ (39)	$ (12)	$ (174)	$ (12)
Derivatives	40	12	179	12
Amounts related to interest settlements on derivatives	28	1	53	1
Total net interest income recognized on fair value hedges	29	1	58	1
Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Hedged items	(3)	7	0	(1)
Derivatives	3	(7)	0	1
Amounts related to interest settlements on derivatives	(3)	(3)	(7)	(8)
Total net interest income recognized on fair value hedges	$ (3)	$ (3)	$ (7)	$ (8)

Change in Unrealized Gain (Loss) on Settlements on Derivatives

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- Definition

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 815
-SubTopic 25
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480238/815-25-50-1

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- Definition

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

+ References

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- Definition

Amount of gain (loss) on derivative instrument designated and qualifying as fair value hedge included in assessment of hedge effectiveness, recognized in earnings.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 815
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480627/815-20-45-1A

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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 815
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4E
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480434/815-10-50-4E

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