ACCUMULATED OTHER COMPREHENSIVE (LOSS) INCOME - Schedule of Pretax and After-tax Components of Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI activity before reclassification, net amount	$ 249
Amounts reclassified from AOCI to earnings, net amount	(3)
Other comprehensive income (loss) on securities available for sale and cash flow hedges, gross amount	331	$ (124)
Other comprehensive income (loss) on securities available for sale and cash flow hedges, tax	(85)	33
Other comprehensive income (loss), net of tax	246	(91)
Unrealized loss on securities available for sale:
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss) on securities available for sale and cash flow hedges, gross amount	322	(124)
Other comprehensive income (loss) on securities available for sale and cash flow hedges, tax	(83)	33
Other comprehensive income (loss), net of tax	239	(91)
Unrealized gain on cash flow hedge derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
AOCI activity before reclassification, gross amount	12	0
AOCI activity before reclassification, tax	(2)	0
AOCI activity before reclassification, net amount	10	0
Amounts reclassified from AOCI to earnings, gross amount	(3)	0
Amounts reclassified from AOCI to earnings, tax	0	0
Amounts reclassified from AOCI to earnings, net amount	(3)	0
Other comprehensive income (loss) on securities available for sale and cash flow hedges, gross amount	9	0
Other comprehensive income (loss) on securities available for sale and cash flow hedges, tax	(2)	0
Other comprehensive income (loss), net of tax	$ 7	$ 0

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.

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