SECURITIES - Schedule of Amortized Cost and Fair Value of Securities Available for Sale (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Schedule of Investments [Line Items]
Amortized Cost	$ 3,460	$ 3,622
Gross Unrealized Gains	10	1
Gross Unrealized Losses	(216)	(348)
Fair Value	3,254	3,275
U.S. Treasury
Schedule of Investments [Line Items]
Amortized Cost	422	278
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(2)	(21)
Fair Value	420	257
U.S. government agencies
Schedule of Investments [Line Items]
Amortized Cost	78	107
Gross Unrealized Gains	1	1
Gross Unrealized Losses	0	0
Fair Value	79	108
U.S. government-sponsored entities
Schedule of Investments [Line Items]
Amortized Cost	227	283
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(4)	(21)
Fair Value	223	262
Agency mortgage-backed securities
Schedule of Investments [Line Items]
Amortized Cost	814	1,360
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(62)	(128)
Fair Value	752	1,232
Agency collateralized mortgage obligations
Schedule of Investments [Line Items]
Amortized Cost	946	1,110
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(114)	(138)
Fair Value	832	972
Commercial mortgage-backed securities
Schedule of Investments [Line Items]
Amortized Cost	905	430
Gross Unrealized Gains	9	0
Gross Unrealized Losses	(30)	(35)
Fair Value	884	395
States of the U.S. and political subdivisions (municipals)
Schedule of Investments [Line Items]
Amortized Cost	30	33
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(3)	(4)
Fair Value	27	29
Other debt securities
Schedule of Investments [Line Items]
Amortized Cost	38	21
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(1)	(1)
Fair Value	$ 37	$ 20