Separate Accounts, Death Benefits and Other Insurance Benefit Features and Embedded Product Derivative - Corporate Account Investments of Account Balances of Variable Annuity Contracts with Guarantees (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Insurance [Abstract]
Debt securities	$ 313.4	$ 322.1
Equity funds	1,476.4	1,538.7
Other	45.7	47.4
Total	$ 1,835.5	$ 1,908.2