CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY (Parentheticals) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Change in unrealized appreciation (depreciation) of investments, applicable income tax expense (benefit)	$ 121.5	$ (231.7)	$ 52.3
Change in noncredit component of impairment losses on fixed maturities, available for sale, applicable income tax expense (benefit)	$ (0.8)	$ (1.2)	$ (0.4)