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ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME - Schedule of Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Millions | Jun. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Pretax | $ (798) | $ (637)
Income Taxes | 188 | 146
Net of Income Taxes | (610) | (491)
Unrealized loss on securities available for sale |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Pretax | (906) | (752)
Income Taxes | 216 | 175
Net of Income Taxes | (690) | (577)
Unrealized loss on securities available for sale transferred to held to maturity |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Pretax | (7) | (7)
Income Taxes | 2 | 2
Net of Income Taxes | (5) | (5)
Defined benefit pension items |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Pretax | 112 | 122
Income Taxes | (29) | (31)
Net of Income Taxes | 83 | 91
Unrealized gain on cash flow hedge derivatives |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |
Pretax | 3 | 0
Income Taxes | (1) | 0
Net of Income Taxes | $ 2 | $ 0

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