Income Taxes - Statutory Federal Income Tax Expense, Effective Income Tax Expense, Rates (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Taxes [Abstract]
Statutory Federal Income Tax Expense	$ (42.8)	$ (23.9)	$ (79.3)
Statutory Federal Income Tax Expense, Rate	35.00%	35.00%	35.00%
Tax-exempt Income and Dividends Received Deduction	13.9	17.7	19.0
Tax-exempt Income and Dividends Received Deduction, Rate	(11.40%)	(26.00%)	(8.40%)
State Income Taxes	(0.8)	(1.0)	(1.0)
State Income Taxes, Rate	0.70%	1.50%	0.40%
Nondeductible Goodwill	0	0	(5.2)
Nondeductible Goodwill, Rate	0.00%	0.00%	2.30%
Other, Net	(0.9)	0.6	2.7
Other, Net, Rate	0.70%	(1.00%)	(1.10%)
Effective Income Tax Expense	$ (30.6)	$ (6.6)	$ (63.8)
Effective Income Tax Expense, Rate	25.00%	9.50%	28.20%