ACCOUNTING FOR DERIVATIVES - FAIR VALUE BY BALANCE SHEET LOCATION (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Fixed index call options
Derivatives, Fair Value [Line Items]
Assets	$ 193.4	$ 216.7
Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Assets	195.4	218.1
Liabilities	1,704.2	1,644.5
Not Designated as Hedging Instrument \| Fixed index call options \| Other invested assets:
Derivatives, Fair Value [Line Items]
Assets	193.4	216.7
Not Designated as Hedging Instrument \| Other \| Other invested assets:
Derivatives, Fair Value [Line Items]
Assets	2.5	0.0
Not Designated as Hedging Instrument \| Reinsurance receivables \| Reinsurance receivables
Derivatives, Fair Value [Line Items]
Assets	(0.5)	1.4
Not Designated as Hedging Instrument \| Fixed index products \| Future policy benefits:
Derivatives, Fair Value [Line Items]
Liabilities	$ 1,704.2	$ 1,644.5

Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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