INVESTMENT SECURITIES (Rollforward of Total Amount of Credit-Related OTTI) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Net Investment Income [Line Items]
Available-for-sale	$ 83	$ 85	$ 251	$ 237
Held-to-maturity	55	59	168	181
Total investment securities	138	144	419	418
Taxable
Net Investment Income [Line Items]
Available-for-sale	75	76	227	214
Held-to-maturity	54	58	165	178
Total investment securities	129	134	392	392
Nontaxable
Net Investment Income [Line Items]
Available-for-sale	8	9	24	23
Held-to-maturity	1	1	3	3
Total investment securities	$ 9	$ 10	$ 27	$ 26

Amount of operating interest income, including amortization and accretion of premiums and discounts, on held-to-maturity securities.

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Amount of interest income, amortization of premium and accretion of discount on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale); classified as operating.

+ References

No definition available.

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Amount of interest income, amortization of premium and accretion of discount, on 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); classified as operating.

+ References

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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 944
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(2)(a))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477250/944-220-S99-1

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