INVESTMENTS (SCHEDULE OF CREDIT LOSSES RECOGNIZED IN EARNINGS) (Details) - Available-for-sale securities [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Credit losses on fixed maturity securities, available for sale, beginning of period	$ (2.6)	$ (1.0)	$ (1.3)
Add: credit losses on other-than-temporary impairments not previously recognized	(3.0)	(2.0)	0.0
Less: credit losses on securities sold	0.1	0.4	0.3
Less: credit losses on securities impaired due to intent to sell	0.0	0.0	0.0
Add: credit losses on previously impaired securities	0.0	0.0	0.0
Less: increases in cash flows expected on previously impaired securities	0.0	0.0	0.0
Credit losses on fixed maturity securities, available for sale, end of period	$ (5.5)	$ (2.6)	$ (1.0)