BUSINESS COMBINATIONS - Narrative (Details) - USD ($) $ in Millions		12 Months Ended
	Oct. 20, 2025	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Jun. 09, 2021
Business Combination [Line Items]
Preliminary goodwill		$ 5,997	$ 5,561	$ 5,561
Veritex Holdings, Inc.
Business Combination [Line Items]
Share issuance ratio	1.95
Consideration transferred	$ 1,684
Preliminary goodwill	450
Servicing rights and other intangible assets	$ 105
Acquisition-related expenses		$ 125
Veritex Holdings, Inc. | Core deposit intangible
Business Combination [Line Items]
Servicing rights and other intangible assets					$ 95
Useful life		10 years
Veritex Holdings, Inc. | Veritex Shareholders Common Stock
Business Combination [Line Items]
Shares issued (in shares)	107,000,000
Veritex Holdings, Inc. | Conversion Of Certain Veritex Equity Awards
Business Combination [Line Items]
Shares issued (in shares)	1,000,000