Separate Accounts, Death Benefits and Other Insurance Benefit Features and Embedded Product Derivative - Non-Insurance Guaranteed Product Features (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Variable Annuity Embedded Derivatives Table [Line Items]
GMWB	$ 3.2	$ 5.1
GMAB	0	(1.4)
COMBO	0.3	0.4
Total variable annuity embedded derivative liabilities	3.5	4.1
Average Attained Age of Annuitant	65 years	64 years
GMWB
Variable Annuity Embedded Derivatives Table [Line Items]
Average Attained Age of Annuitant	64 years	64 years
GMAB
Variable Annuity Embedded Derivatives Table [Line Items]
Average Attained Age of Annuitant	59 years	59 years
COMBO
Variable Annuity Embedded Derivatives Table [Line Items]
Average Attained Age of Annuitant	63 years	63 years
Account Value
Variable Annuity Embedded Derivatives Table [Line Items]
GMWB	530.9	551.1
GMAB	352.8	370.9
COMBO	7.0	7.0
Total variable annuity embedded derivative liabilities	$ 890.7	$ 929.0