Investments - Schedule of Other Than Temporary Impairment (Details) - Fixed Maturities [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward]
Cumulative Balance of Pre-tax Credit Losses Recognized in Retained Earnings at Beginning of Period	$ 4.2	$ 5.3	$ 5.1	$ 5.3
Pre-tax Credit Losses on Fixed Maturities without Pre-tax Credit Losses Included in Cumulative Balance at Beginning of Period	0.0	0.0	2.7	0.0
From Status of Credit Loss to Status of Intent-to-sell or Required-to-sell	(2.7)	0.0	(6.3)	0.0
Cumulative Balance of Pre-tax Credit Losses Recognized in Retained Earnings at End of Period	$ 1.5	$ 5.3	$ 1.5	$ 5.3