Fair Value of Financial Instruments Fair Value of Financial Instruments - Quantitative Estimates for Level 3 Liabilities (Details) (Level 3, USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
EIA/VED Embedded Derivative
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Embedded derivatives	$ 107.4	$ 78.9
GMAB/GMWB Embedded Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Embedded derivatives	$ (3.9)	$ (4.1)
Income Approach Valuation Technique | EIA/VED Embedded Derivative
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, CSA Rate	2.92%	3.23%
Income Approach Valuation Technique | GMAB/GMWB Embedded Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Mortality Rate	105.00%	105.00%
Fair Value Inputs, CSA Rate	2.92%	3.23%
Minimum | Income Approach Valuation Technique | EIA/VED Embedded Derivative
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Swap Curve	0.18%	0.19%
Fair Value Inputs, Mortality Rate	97.00%	97.00%
Lapse rate	0.02%	0.02%
Minimum | Income Approach Valuation Technique | GMAB/GMWB Embedded Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Swap Curve	0.16%	0.15%
Lapse rate	0.00%	0.00%
Fair Value Inputs, Volatility Surface	8.89%	10.85%
Maximum | Income Approach Valuation Technique | EIA/VED Embedded Derivative
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Swap Curve	3.15%	3.79%
Fair Value Inputs, Mortality Rate	103.00%	103.00%
Lapse rate	47.15%	47.15%
Maximum | Income Approach Valuation Technique | GMAB/GMWB Embedded Derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair Value Inputs, Swap Curve	3.48%	4.15%
Lapse rate	40.00%	40.00%
Fair Value Inputs, Volatility Surface	44.06%	46.33%