SECURITIES - Schedule of Amortized Cost and Fair Value of Securities Available for Sale (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 3,620	$ 3,460
Gross Unrealized Gains	4	10
Gross Unrealized Losses	(158)	(216)
Fair Value	3,466	3,254
U.S. Treasury
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	274	422
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(1)	(2)
Fair Value	274	420
U.S. government agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	53	78
Gross Unrealized Gains	0	1
Gross Unrealized Losses	0	0
Fair Value	53	79
U.S. government-sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	302	227
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	(4)
Fair Value	300	223
Agency MBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	714	814
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(20)	(62)
Fair Value	694	752
Agency collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	796	946
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(98)	(114)
Fair Value	698	832
Agency commercial MBS
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,420	905
Gross Unrealized Gains	3	9
Gross Unrealized Losses	(35)	(30)
Fair Value	1,388	884
States of the U.S. and political subdivisions (municipals)
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	24	30
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	(3)
Fair Value	22	27
Other debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	37	38
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(1)
Fair Value	$ 37	$ 37

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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