INVESTMENT SECURITIES - Schedule of Amortized Cost and Fair Value of Securities, by Contractual Maturities (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Amortized Cost
Available for sale, due in one year or less, amortized cost	$ 180
Available for sale, due after one year but within five years, amortized cost	432
Available for sale, due after five years but within ten years, amortized cost	95
Available for sale, due after ten years, amortized cost	18
Available for sale, with contractual maturities, amortized cost	725
Amortized Cost	3,783	$ 3,620
Fair Value
Available for sale, due in one year or less, fair value	181
Available for sale, due after one year but within five years, fair value	433
Available for sale, due after five years but within ten years, fair value	96
Available for sale, due after ten years, fair value	17
Available for sale, with contractual maturities, fair value	727
Fair Value	3,727	3,466
Amortized Cost
Held to maturity, due in one year or less, amortized cost	4
Held to maturity, due after one year but within five years, amortized cost	100
Held to maturity, due after five years but within ten years, amortized cost	259
Held to maturity, due after ten years, amortized cost	643
Held to maturity, with contractual maturities, amortized cost	1,006
Amortized Cost	4,117	3,979
Fair Value
Held to maturity, due in one year or less, fair value	4
Held to maturity, due after one year but within five years, fair value	97
Held to maturity, due after five years but within ten years, fair value	249
Held to maturity, due after ten years, fair value	596
Held to maturity, with contractual maturities, fair value	946
Fair Value	3,941	3,644
Agency MBS
Amortized Cost
Available-for-sale, amortized cost	801
Amortized Cost	801	714
Fair Value
Available for sale, fair value	800
Fair Value	800	694
Amortized Cost
Held to maturity, amortized cost	784
Amortized Cost	784	901
Fair Value
Held to maturity, fair value	731
Fair Value	731	806
Agency CMO
Amortized Cost
Available-for-sale, amortized cost	662
Amortized Cost	662	796
Fair Value
Available for sale, fair value	601
Fair Value	601	698
Amortized Cost
Held to maturity, amortized cost	612
Amortized Cost	612	714
Fair Value
Held to maturity, fair value	550
Fair Value	550	619
Agency commercial MBS
Amortized Cost
Available-for-sale, amortized cost	1,595
Amortized Cost	1,595	1,420
Fair Value
Available for sale, fair value	1,599
Fair Value	1,599	1,388
Amortized Cost
Held to maturity, amortized cost	1,715
Amortized Cost	1,715	1,326
Fair Value
Held to maturity, fair value	1,714
Fair Value	$ 1,714	$ 1,284