Separate Accounts, Death Benefits and Other Insurance Benefit Features and Embedded Product Derivatives - Non-Insurance Guaranteed Product Features(Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended			9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Account Value	Dec. 31, 2013 Account Value	Sep. 30, 2014 GMWB	Dec. 31, 2013 GMWB	Sep. 30, 2014 GMAB	Dec. 31, 2013 GMAB	Sep. 30, 2014 COMBO	Dec. 31, 2013 COMBO
Variable Annuity Embedded Derivatives Table [Line Items]
GMWB	$ 1.2	$ (5.1)	$ 491.3	$ 551.1
GMAB	0.5	1.4	318.2	370.9
COMBO	(0.3)	(0.4)	6.9	7.0
Total variable annuity embedded derivative liabilities	$ 1.4	$ (4.1)	$ 816.4	$ 929.0
Average Attained Age of Annuitant	65 years	64 years			64 years	64 years	59 years	59 years	64 years	63 years