STATUTORY INFORMATION (BASED ON NON-GAAP MEASURES) (SCHEDULE OF STATUTORY ACCOUNTING PRACTICES) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Insurance [Abstract]
Statutory capital and surplus	$ 1,956.8	$ 1,739.2
Asset valuation reserve	253.3	196.9
Interest maintenance reserve	486.9	476.0
Total	$ 2,697.0	$ 2,412.1