SECURITIZATIONS AND VARIABLE INTEREST ENTITIES - Loan Delinquencies and Liquidation Losses (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Residential mortgages
Variable Interest Entity
Securitized assets	$ 31,500.0		$ 30,800.0
Liquidation losses	2.3	$ 1.5
Commercial and other
Variable Interest Entity
Securitized assets	28,800.0		28,800.0
Liquidation losses	0.0	0.0
Mortgage securitizations - Non-agency-sponsored
Variable Interest Entity
Securitized assets	60,300.0		59,600.0
Liquidation losses	2.3	$ 1.5
Personal loan
Variable Interest Entity
Securitized assets	100.0
90+ days past due | Residential mortgages
Variable Interest Entity
Securitized assets	500.0		500.0
90+ days past due | Commercial and other
Variable Interest Entity
Securitized assets	0.0		0.0
90+ days past due | Mortgage securitizations - Non-agency-sponsored
Variable Interest Entity
Securitized assets	$ 500.0		$ 500.0