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INVESTMENT SECURITIES - Narrative (Details) shares in Thousands | 3 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2024 USD ($) security shares | Jun. 30, 2023 USD ($) | Jun. 30, 2024 USD ($) security shares | Jun. 30, 2023 USD ($) | Jan. 24, 2024 shares | Dec. 31, 2023 USD ($)
Schedule of Investments [Line Items] |  |  |  |  |  |
Debt securities, available-for-sale, accrued Interest | $ 136,000,000 |  | $ 136,000,000 |  |  | $ 87,000,000
Debt Securities, held-to-maturity, accrued interest | 20,000,000 |  | 20,000,000 |  |  | 18,000,000
Write off of accrued interest receivable | $ 0 | $ 0 | $ 0 | $ 0 |  |
Debt securities, held-to-maturity, threshold period past due | 30 days |  | 30 days |  |  |
Securities past due | $ 10,535,000,000 |  | $ 10,535,000,000 |  |  | 9,979,000,000
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, number of positions | security | 524 |  | 524 |  |  |
Securities, nonaccrual | $ 0 |  | $ 0 |  |  | 0
Total Past Due |  |  |  |  |  |
Schedule of Investments [Line Items] |  |  |  |  |  |
Securities past due | 0 |  | 0 |  |  | 0
Asset Pledged as Collateral |  |  |  |  |  |
Schedule of Investments [Line Items] |  |  |  |  |  |
Investment securities, aggregate carrying value, pledged as collateral | $ 3,890,000,000 |  | $ 3,890,000,000 |  |  | $ 3,770,000,000
Visa, Inc | Class B |  |  |  |  |  |
Schedule of Investments [Line Items] |  |  |  |  |  |
Investment owned (in shares) | shares | 354 |  | 354 |  |  |
Visa, Inc | Class B-1 |  |  |  |  |  |
Schedule of Investments [Line Items] |  |  |  |  |  |
Investment owned (in shares) | shares |  |  |  |  | 354 |
Residential Mortgage Backed Securities or Government Agency Securities |  |  |  |  |  |
Schedule of Investments [Line Items] |  |  |  |  |  |
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, number of positions | security | 453 |  | 453 |  |  |
Corporate Bonds |  |  |  |  |  |
Schedule of Investments [Line Items] |  |  |  |  |  |
Available-for-sale securities, continuous unrealized loss position, 12 months or longer, number of positions | security | 71 |  | 71 |  |  |

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