MORTGAGE BANKING AND OTHER SERVICED LOANS - Residential Mortgage Loan Sales (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Residential mortgages
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Cash proceeds from residential mortgage loans sold with servicing retained	$ 2,528	$ 2,137	$ 6,920	$ 5,432
Mortgage banking fees
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Gain on sales	19	17	56	47
Contractually specified servicing, late and other ancillary fees	$ 70	$ 79	$ 209	$ 235