Investments - Schedule of Other Than Temporary Impairment (Details) - Fixed Maturities [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
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	$ 5.3	$ 10.2	$ 5.3	$ 9.9
Pre-tax Credit Losses on Fixed Maturities without Pre-tax Credit Losses Included in Cumulative Balance at Beginning of Period	0.0	2.4	0.0	2.4
Additional Pre-tax Credit Losses on Fixed Maturities with Pre-tax Credit Losses Included in Cumulative Balance at Beginning of Period	0.0	0.3	0.0	0.6
Cumulative Balance of Pre-tax Credit Losses Recognized in Retained Earnings at End of Period	$ 5.3	$ 12.9	$ 5.3	$ 12.9