DERIVATIVES (FAIR VALUE BY BALANCE SHEET LOCATION) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Equity Contract [Member]
Derivatives, Fair Value [Line Items]
Gross derivative asset	$ 111.9	$ 41.0
Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Gross derivative asset	0.0	0.1
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Gross derivative asset	107.7	36.1
Gross derivative liability	1,092.3	1,057.1
Not Designated as Hedging Instrument [Member] | Equity Contract [Member] | Other Invested Assets [Member]
Derivatives, Fair Value [Line Items]
Gross derivative asset	111.9	41.0
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Other Invested Assets [Member]
Derivatives, Fair Value [Line Items]
Gross derivative asset	0.0	0.1
Not Designated as Hedging Instrument [Member] | Reinsurance Receivables - Embedded Derivative [Member] | Other Invested Assets [Member]
Derivatives, Fair Value [Line Items]
Gross derivative asset	(4.2)	(5.0)
Not Designated as Hedging Instrument [Member] | Fixed Index Products [Member] | Future Policy Benefits [Member]
Derivatives, Fair Value [Line Items]
Gross derivative liability	$ 1,092.3	$ 1,057.1