FAIR VALUE MEASURES - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) from change in fair value of mortgages loans held for sale	$ 37.7	$ 4.1	$ 4.6
Net gain (loss) from changes in fair value of related derivative financial instruments	$ (9.3)	$ 1.8	$ (3.0)