MORTGAGE LOAN SALES AND SERVICING RIGHTS - Residential Mortgage Portfolio, MSRs Fair Value Method (Details) - Residential mortgage - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Servicing Asset at Fair Value, Amount [Roll Forward]
Fair value, beginning of period	$ 567	$ 543	$ 573	$ 515
New servicing assets created	27	12	67	33
Time decay	(6)	(6)	(20)	(19)
Payoffs	(11)	(9)	(28)	(21)
Changes in valuation inputs or assumptions	(1)	(25)	(16)	7
Fair value, end of period	576	515	576	515
Related loans serviced for third parties, unpaid principal balance, end of period	$ 34,370	$ 33,565	$ 34,370	$ 33,565