FAIR VALUE MEASUREMENTS - FAIR VALUE ACTIVITY (Details) - Significant unobservable inputs (Level 3) - Fair Value, Measurements, Recurring - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Embedded derivatives associated with fixed index annuity products (classified as policyholder account liabilities)
Liabilities:
Purchases	$ (44.3)	$ (38.8)	$ (85.9)	$ (89.6)
Sales	0.0	0.1	0.0	119.3
Issuances	(57.1)	(49.0)	(109.9)	(49.0)
Settlements	16.4	21.4	42.5	46.6
Purchases, sales, issuances and settlements, net	(85.0)	(66.3)	(153.3)	27.3
Corporate securities
Assets:
Purchases		0.0	0.0	0.0
Sales		(0.1)	(0.1)	(2.3)
Issuances		0.0	0.0	0.0
Settlements		0.0	0.0	0.0
Purchases, sales, issuances and settlements, net	0.0	(0.1)	(0.1)	(2.3)
Asset-backed securities
Assets:
Purchases	0.0	0.0	0.0	0.0
Sales	(0.1)	(0.1)	(0.3)	(0.3)
Issuances	0.0	0.0	0.0	0.0
Settlements	0.0	0.0	0.0	0.0
Purchases, sales, issuances and settlements, net	(0.1)	(0.1)	(0.3)	(0.3)
Total fixed maturities, available for sale
Assets:
Purchases		0.0	0.0	0.0
Sales		(1.4)	(0.4)	(2.6)
Issuances		0.0	0.0	0.0
Settlements		0.0	0.0	0.0
Purchases, sales, issuances and settlements, net	(0.1)	(1.4)	(0.4)	(2.6)
Non-agency residential mortgage-backed securities
Assets:
Purchases, sales, issuances and settlements, net			0.0
Commercial mortgage-backed securities
Assets:
Purchases		0.0
Sales		(1.2)
Issuances		0.0
Settlements		0.0
Purchases, sales, issuances and settlements, net		(1.2)
Equity securities - corporate securities
Assets:
Purchases	0.2		0.2
Sales	0.0		0.0
Issuances	0.0		0.0
Settlements	0.0		0.0
Purchases, sales, issuances and settlements, net	0.2	$ 0.0	0.2	$ 0.0
Non-agency residential mortgage-backed securities
Assets:
Purchases	0.0		0.0
Sales	(0.8)		(1.1)
Issuances	0.0		0.0
Settlements	0.0		0.0
Purchases, sales, issuances and settlements, net	$ (0.8)		$ (1.1)

Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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