FAIR VALUE MEASURES - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fair Value Disclosures [Abstract]
Net gains (losses) from change in fair value of mortgages loans held for sale	$ 10.0	$ 26.1	$ (15.1)	$ 41.1
Net gains (losses) from change in fair value of derivative financial instruments	$ (45.1)	$ 36.4	$ (17.6)	$ 33.8

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=121577467&loc=d3e76258-113986

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration