Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net Loss	$ (0.3)	$ (2.1)
Other Comprehensive Income Before Income Taxes:
Unrealized Holding Gains	28.5	100.7
Foreign Currency Translation Adjustments	0.1	0.1
Decrease (Increase) in Net Unrecognized Postretirement Benefit Costs	(0.1)	1.8
Loss on Cash Flow Hedge	(2.0)	0.0
Other Comprehensive Income Before Income Taxes	26.5	102.6
Other Comprehensive Income Tax Expense	(9.4)	(36.2)
Other Comprehensive Income	17.1	66.4
Total Comprehensive Income	$ 16.8	$ 64.3