INVESTMENT SECURITIES (Summary of Amount of Gross Unrealized Losses for Debt Securities and Estimated Fair Value) (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Available-for-sale, less than 12 Months	$ 19	$ 2
Available-for-sale, less than 12 Months, estimated fair value	1,417	299
Available-for-sale, 12 Months or more	1,177	1,166
Available-for-sale, 12 months or more, estimated fair value	6,924	7,425
Available-for-sale, total	1,196	1,168
Available-for-sale, total, estimated fair value	8,341	7,724
U.S. Treasury securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Available-for-sale, less than 12 Months	16	0
Available-for-sale, less than 12 Months, estimated fair value	1,087	99
Available-for-sale, 12 Months or more	109	106
Available-for-sale, 12 months or more, estimated fair value	293	296
Available-for-sale, total	125	106
Available-for-sale, total, estimated fair value	1,380	395
Agency securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Available-for-sale, less than 12 Months	0	0
Available-for-sale, less than 12 Months, estimated fair value	4	7
Available-for-sale, 12 Months or more	15	15
Available-for-sale, 12 months or more, estimated fair value	253	288
Available-for-sale, total	15	15
Available-for-sale, total, estimated fair value	257	295
Agency guaranteed mortgage-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Available-for-sale, less than 12 Months	3	2
Available-for-sale, less than 12 Months, estimated fair value	206	86
Available-for-sale, 12 Months or more	996	987
Available-for-sale, 12 months or more, estimated fair value	5,400	5,735
Available-for-sale, total	999	989
Available-for-sale, total, estimated fair value	5,606	5,821
Small Business Administration loan-backed securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Available-for-sale, less than 12 Months	0	0
Available-for-sale, less than 12 Months, estimated fair value	24	24
Available-for-sale, 12 Months or more	13	14
Available-for-sale, 12 months or more, estimated fair value	260	309
Available-for-sale, total	13	14
Available-for-sale, total, estimated fair value	284	333
Municipal securities
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Available-for-sale, less than 12 Months	0	0
Available-for-sale, less than 12 Months, estimated fair value	81	68
Available-for-sale, 12 Months or more	44	44
Available-for-sale, 12 months or more, estimated fair value	718	797
Available-for-sale, total	44	44
Available-for-sale, total, estimated fair value	799	865
Other
Debt Securities, Available-for-sale, Unrealized Loss Position [Line Items]
Available-for-sale, less than 12 Months	0	0
Available-for-sale, less than 12 Months, estimated fair value	15	15
Available-for-sale, 12 Months or more	0	0
Available-for-sale, 12 months or more, estimated fair value	0	0
Available-for-sale, total	0	0
Available-for-sale, total, estimated fair value	$ 15	$ 15

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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