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INVESTMENT SECURITIES - Schedule of Amortized Cost and Fair Value of Investment Securities (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Investment securities available for sale
Amortized Cost	$ 31,952	$ 34,512
Gross Unrealized Gains	341	81
Gross Unrealized Losses	(503)	(843)
Investment securities available for sale	31,790	33,750
Investment in marketable equity securities
Amortized Cost	83	79
Gross Unrealized Gains	44	27
Gross Unrealized Losses	0	(5)
Fair Value	127	101
Investment securities held to maturity
Amortized Cost	9,647	10,239
Gross Unrealized Gains	32	2
Gross Unrealized Losses	(1,188)	(1,539)
Fair Value	8,491	8,702
Total investment securities
Amortized Cost	41,682	44,830
Gross Unrealized Gains	417	110
Gross Unrealized Losses	(1,691)	(2,387)
Fair Value	40,408	42,553
U.S. Treasury
Investment securities available for sale
Amortized Cost	10,624	13,897
Gross Unrealized Gains	50	33
Gross Unrealized Losses	(1)	(27)
Investment securities available for sale	10,673	13,903
Investment securities held to maturity
Amortized Cost	388	483
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(15)	(31)
Fair Value	373	452
Government agency
Investment securities available for sale
Amortized Cost	44	79
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(2)
Investment securities available for sale	43	77
Investment securities held to maturity
Amortized Cost	1,225	1,489
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(55)	(115)
Fair Value	1,170	1,374
Residential mortgage-backed securities
Investment securities available for sale
Amortized Cost	17,683	16,161
Gross Unrealized Gains	263	41
Gross Unrealized Losses	(323)	(582)
Investment securities available for sale	17,623	15,620
Investment securities held to maturity
Amortized Cost	4,450	4,558
Gross Unrealized Gains	32	2
Gross Unrealized Losses	(490)	(682)
Fair Value	3,992	3,878
Commercial mortgage-backed securities
Investment securities available for sale
Amortized Cost	3,444	3,869
Gross Unrealized Gains	28	7
Gross Unrealized Losses	(173)	(210)
Investment securities available for sale	3,299	3,666
Investment securities held to maturity
Amortized Cost	3,337	3,407
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(608)	(678)
Fair Value	2,729	2,729
Corporate bonds
Investment securities available for sale
Amortized Cost	145	489
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(5)	(22)
Investment securities available for sale	140	467
Municipal bonds
Investment securities available for sale
Amortized Cost	12	17
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Investment securities available for sale	12	17
Supranational securities
Investment securities held to maturity
Amortized Cost	246	300
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(20)	(33)
Fair Value	226	267
Other
Investment securities held to maturity
Amortized Cost	1	2
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	$ 1	$ 2

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