GOODWILL AND OTHER INTANGIBLE ASSETS - Schedule of Goodwill (Details) $ in Millions	12 Months Ended
	Dec. 31, 2025 USD ($)
Goodwill by business segment
Balance at beginning of period	$ 5,561
Veritex acquisition	450
Sale of a portion of corporate trust and custody business	(14)
Balance at end of period	5,997
Operating Segments | Consumer & Regional Banking
Goodwill by business segment
Balance at beginning of period	3,640
Veritex acquisition	229
Sale of a portion of corporate trust and custody business	(14)
Balance at end of period	3,855
Operating Segments | Commercial Banking
Goodwill by business segment
Balance at beginning of period	1,921
Veritex acquisition	221
Sale of a portion of corporate trust and custody business	0
Balance at end of period	$ 2,142