INVESTMENT SECURITIES - Schedule of Unrealized Losses (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Investment securities available for sale
Investment securities available for sale, less than 12 months, fair value	$ 1,001	$ 12,460
Investment securities available for sale, less than 12 months, unrealized losses	(2)	(81)
Investment securities available for sale, 12 months or more, fair value	5,220	6,413
Investment securities available for sale, 12 months or more, unrealized losses	(539)	(762)
Investment securities available for sale, fair value	6,221	18,873
Investment securities available for sale, unrealized losses	(541)	(843)
U.S. Treasury
Investment securities available for sale
Investment securities available for sale, less than 12 months, fair value	501	3,791
Investment securities available for sale, less than 12 months, unrealized losses	(1)	(12)
Investment securities available for sale, 12 months or more, fair value	400	981
Investment securities available for sale, 12 months or more, unrealized losses	(1)	(15)
Investment securities available for sale, fair value	901	4,772
Investment securities available for sale, unrealized losses	(2)	(27)
Government agency
Investment securities available for sale
Investment securities available for sale, less than 12 months, fair value	0	0
Investment securities available for sale, less than 12 months, unrealized losses	0	0
Investment securities available for sale, 12 months or more, fair value	52	77
Investment securities available for sale, 12 months or more, unrealized losses	(1)	(2)
Investment securities available for sale, fair value	52	77
Investment securities available for sale, unrealized losses	(1)	(2)
Residential mortgage-backed securities
Investment securities available for sale
Investment securities available for sale, less than 12 months, fair value	403	7,470
Investment securities available for sale, less than 12 months, unrealized losses	(1)	(61)
Investment securities available for sale, 12 months or more, fair value	3,381	3,575
Investment securities available for sale, 12 months or more, unrealized losses	(350)	(521)
Investment securities available for sale, fair value	3,784	11,045
Investment securities available for sale, unrealized losses	(351)	(582)
Commercial mortgage-backed securities
Investment securities available for sale
Investment securities available for sale, less than 12 months, fair value	96	1,183
Investment securities available for sale, less than 12 months, unrealized losses	0	(8)
Investment securities available for sale, 12 months or more, fair value	1,175	1,342
Investment securities available for sale, 12 months or more, unrealized losses	(181)	(202)
Investment securities available for sale, fair value	1,271	2,525
Investment securities available for sale, unrealized losses	(181)	(210)
Corporate Bonds
Investment securities available for sale
Investment securities available for sale, less than 12 months, fair value	1	16
Investment securities available for sale, less than 12 months, unrealized losses	0	0
Investment securities available for sale, 12 months or more, fair value	212	438
Investment securities available for sale, 12 months or more, unrealized losses	(6)	(22)
Investment securities available for sale, fair value	213	454
Investment securities available for sale, unrealized losses	$ (6)	$ (22)

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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