LOANS - Consumer Loans Gross Credit Losses (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 2,690	$ 1,634
Consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,512	1,595
Consumer loans \| Residential mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0	0
2023	0	0
2022	0	0
2021	0	1
2020	0	1
Prior	14	12
Total	14	14
Consumer loans \| Home equity line of credit (pre-reset)
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1	0
Consumer loans \| Home equity line of credit (post-reset)
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1	0
Consumer loans \| Home equity term loans
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving loans converted to term loans	0	1
Consumer loans \| Home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2	1
Consumer loans \| Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving loans converted to term loans	57	42
Total	2,237	1,366
Consumer loans \| Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,294	1,408
Consumer loans \| Personal, small business and other
Financing Receivable, Credit Quality Indicator [Line Items]
2024	29	38
2023	46	37
2022	52	29
2021	20	13
2020	8	13
Prior	47	42
Total	$ 202	$ 172

Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-6

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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