- Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Unrealized Gains on Investments, Net of Income Taxes:
Available for Sale Fixed Maturities with Portion of OTTI Recognized in Earnings	$ 0.1	$ 1.4
Other Net Unrealized Gains on Investments	211.7	211.7
Foreign Currency Translation Adjustments, Net of Income Taxes	(0.9)	(0.7)
Net Unrecognized Postretirement Benefit Costs, Net of Income Taxes	(74.9)	(88.1)
Gain on Cash Flow Hedge, Net of Income Taxes	1.0	0.0
Accumulated Other Comprehensive Income	$ 137.0	$ 124.3