INVESTMENT SECURITIES - Schedule of AFS Securities Maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Amortized Cost
Available-for-sale, amortized cost	$ 15,249,174	$ 13,813,551
Fair  Value
Total fair value	14,891,506	13,580,285
Total AFS Investment Securities
Amortized Cost
Due within one year	1,713,696
Due after one year through five years	6,891,918
Due after five years through ten years	4,425,272
Due after ten years	2,218,288
Available-for-sale, amortized cost	15,249,174	13,813,551
Fair  Value
Due within one year	1,702,881
Due after one year through five years	6,809,890
Due after five years through ten years	4,268,480
Due after ten years	2,110,255
Total fair value	$ 14,891,506	13,580,285
Weighted-Average Yield
Due within one year	3.35%
Due after one year through five years	4.06%
Due after five years through ten years	3.84%
Due after ten years	4.11%
Weighted-average yield	3.92%
Available-for-sale, accrued interest excluded	$ 98,900	$ 91,300