MORTGAGE LOAN SALES AND SERVICING RIGHTS - Residential Mortgage Portfolio, MSRs Fair Value Method (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Servicing Asset at Fair Value, Amount [Roll Forward]
Fair value, beginning of period	$ 573
Fair value, end of period	593	$ 573
Residential mortgage
Servicing Asset at Fair Value, Amount [Roll Forward]
Fair value, beginning of period	573	515
New servicing assets created	93	54
Servicing assets sold	(1)	(1)
Time decay	(27)	(25)
Payoffs	(41)	(30)
Changes in valuation inputs or assumptions	(4)	60
Fair value, end of period	593	573
Related loans serviced for third parties, unpaid principal balance, end of period	$ 34,407	$ 33,696