Fair Values of Financial Instruments Quantitative Information Regarding Significant Unobservable Inputs (Details) (Fair Value, Inputs, Level 3 [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Public Utility, Bonds [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.20% - 0.20% / 0.20%
Fair value of fixed maturity securities	$ 17.4
Fair Value Measurements, Valuation Techniques	- Comparability Adjustment
Public Utility, Bonds [Member] | Minimum [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.002	[1]
Public Utility, Bonds [Member] | Maximum [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.002	[1]
Public Utility, Bonds [Member] | Weighted Average [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.002	[1]
US States and Political Subdivisions Debt Securities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.25% - 0.25% / 0.25% 0.25% - 0.25% / 0.25% 0.15% - 0.15% / 0.15%
Fair value of fixed maturity securities	42.7
Fair Value Measurements, Valuation Techniques	- Comparability Adjustment - Lack of Marketability - Volatility of Credit
US States and Political Subdivisions Debt Securities [Member] | Minimum [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[1]
US States and Political Subdivisions Debt Securities [Member] | Minimum [Member] | lack of marketability [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[2]
US States and Political Subdivisions Debt Securities [Member] | Minimum [Member] | Volatility of Credit [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0015	[3]
US States and Political Subdivisions Debt Securities [Member] | Maximum [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[1]
US States and Political Subdivisions Debt Securities [Member] | Maximum [Member] | lack of marketability [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[2]
US States and Political Subdivisions Debt Securities [Member] | Maximum [Member] | Volatility of Credit [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0015	[3]
US States and Political Subdivisions Debt Securities [Member] | Weighted Average [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[1]
US States and Political Subdivisions Debt Securities [Member] | Weighted Average [Member] | lack of marketability [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[2]
US States and Political Subdivisions Debt Securities [Member] | Weighted Average [Member] | Volatility of Credit [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0015	[3]
Asset-backed Securities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	5.74% - 5.84% / 5.81%
Fair value of fixed maturity securities	0.5
Fair Value Measurements, Valuation Techniques	- Discount for Size
Asset-backed Securities [Member] | Minimum [Member] | Discount for Size [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0574	[4]
Asset-backed Securities [Member] | Maximum [Member] | Discount for Size [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0584	[4]
Asset-backed Securities [Member] | Weighted Average [Member] | Discount for Size [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0581	[4]
All Other Corporate Bonds [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.04% - 2.89% / 0.28% 1.48% - 1.48% / 1.48% 0.10% - 0.50% / 0.24% 0.10% - 1.00% / 0.46% (0.25)% -7.72% / 1.51% Priced at Par
Fair value of fixed maturity securities	391.8
Fair Value Measurements, Valuation Techniques	- Change in Benchmark Reference - Comparability Adjustment - Discount for Size - Lack of Marketability - Volatility of Credit - Market Convention
All Other Corporate Bonds [Member] | Market Convention [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	Priced at Par	[5]
All Other Corporate Bonds [Member] | Minimum [Member] | Change in Benchmark Reference [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	.0004	[6]
All Other Corporate Bonds [Member] | Minimum [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	.0148	[1]
All Other Corporate Bonds [Member] | Minimum [Member] | Discount for Size [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.001	[4]
All Other Corporate Bonds [Member] | Minimum [Member] | lack of marketability [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.001	[2]
All Other Corporate Bonds [Member] | Minimum [Member] | Volatility of Credit [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	-0.0025	[3]
All Other Corporate Bonds [Member] | Maximum [Member] | Change in Benchmark Reference [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	.0289	[6]
All Other Corporate Bonds [Member] | Maximum [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	.0148	[1]
All Other Corporate Bonds [Member] | Maximum [Member] | Discount for Size [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.005	[4]
All Other Corporate Bonds [Member] | Maximum [Member] | lack of marketability [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.01	[2]
All Other Corporate Bonds [Member] | Maximum [Member] | Volatility of Credit [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0772	[3]
All Other Corporate Bonds [Member] | Weighted Average [Member] | Change in Benchmark Reference [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	.0028	[6]
All Other Corporate Bonds [Member] | Weighted Average [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	.0148	[1]
All Other Corporate Bonds [Member] | Weighted Average [Member] | Discount for Size [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0024	[4]
All Other Corporate Bonds [Member] | Weighted Average [Member] | lack of marketability [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0046	[2]
All Other Corporate Bonds [Member] | Weighted Average [Member] | Volatility of Credit [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0151	[3]
Corporate Bond Securities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.25% - 0.25% / 0.25% (0.59)% - 1.00% / 0.27% 0.25% - 0.25% / 0.25% 0.20% - 0.30% / 0.24% (0.30)% - (0.30)% / (0.30)% Priced at Par
Fair value of fixed maturity securities	165.0
Fair Value Measurements, Valuation Techniques	- Change in Benchmark Reference - Comparability Adjustment - Discount for Size - Lack of Marketability - Volatility of Credit - Market Convention
Corporate Bond Securities [Member] | Market Convention [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	Priced at Par	[5]
Corporate Bond Securities [Member] | Minimum [Member] | Change in Benchmark Reference [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[6]
Corporate Bond Securities [Member] | Minimum [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	-0.0059	[1]
Corporate Bond Securities [Member] | Minimum [Member] | Discount for Size [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[4]
Corporate Bond Securities [Member] | Minimum [Member] | lack of marketability [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.002	[2]
Corporate Bond Securities [Member] | Minimum [Member] | Volatility of Credit [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	-0.003	[3]
Corporate Bond Securities [Member] | Maximum [Member] | Change in Benchmark Reference [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[6]
Corporate Bond Securities [Member] | Maximum [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.01	[1]
Corporate Bond Securities [Member] | Maximum [Member] | Discount for Size [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[4]
Corporate Bond Securities [Member] | Maximum [Member] | lack of marketability [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.003	[2]
Corporate Bond Securities [Member] | Maximum [Member] | Volatility of Credit [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	-0.003	[3]
Corporate Bond Securities [Member] | Weighted Average [Member] | Change in Benchmark Reference [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[6]
Corporate Bond Securities [Member] | Weighted Average [Member] | Comparability Adjustment [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0027	[1]
Corporate Bond Securities [Member] | Weighted Average [Member] | Discount for Size [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0025	[4]
Corporate Bond Securities [Member] | Weighted Average [Member] | lack of marketability [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	0.0024	[2]
Corporate Bond Securities [Member] | Weighted Average [Member] | Volatility of Credit [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	-0.003	[3]
Equity Securities [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	Priced at Cost or Owner's Equity	[5]
Fair Value Measurements, Valuation Techniques	- Market Convention
Available-for-sale Securities, Equity Securities	4.0
Embedded Derivative Financial Instruments [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Fair Value Measurements, Significant Assumptions	Actuarial Assumptions	[7]
Fair Value Measurements, Valuation Techniques	- Projected Liability Cash Flows
Embedded Derivative, Fair Value of Embedded Derivative Liability	$ (83.9)

[1] Represents basis point adjustments for changes in benchmark spreads associated with various industry sectors

[2] Represents basis point adjustments to apply a discount due to the illiquidity of an investment

[3] Represents basis point adjustments for credit-specific factors

[4] Represents basis point adjustments based on issue/issuer size relative to the benchmark

[5] Represents a decision to price based on par value, cost, or owner's equity when limited data is available

[6] Represents basis point adjustments for changes in benchmark spreads associated with various ratings categories

[7] Represents various actuarial assumptions required to derive the liability cash flows including incidence, termination, and lapse rates