SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Corporate-Owned Life Insurance (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Cash surrender value of policies	$ 1,370.0	$ 1,441.7
Borrowings against policies	(1,237.1)	(1,306.9)
Corporate-owned life insurance, net	$ 132.9	$ 134.8

This item represents the amount that could be realized under a life insurance contract or contracts owned by the Entity as of the date of the statement of financial position. Such Entity-owned life insurance policies are commonly known as corporate-owned life insurance (COLI) or bank-owned life insurance (BOLI).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 325
-SubTopic 30
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6384206&loc=d3e41899-111602

Name:	us-gaap_LifeInsuranceCorporateOrBankOwnedAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant