Separate Accounts, Death Benefits and Other Insurance Benefit Features and Embedded Product Derivatives - Embedded Derivative Liabilities (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Variable annuity embedded derivative liability	$ 3.1	$ 6.4
GMWB
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Variable annuity embedded derivative liability	4.1	6.9
GMAB
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Variable annuity embedded derivative liability	(0.8)	(0.3)
COMBO
Liabilities for Guarantees on Long-Duration Contracts [Line Items]
Variable annuity embedded derivative liability	$ (0.2)	$ (0.2)