Commitments and Contingencies (Restricted Assets) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Loss Contingencies [Line Items]
Fixed maturity collateral pledged to FHLB	$ 2,365.6		$ 2,333.4
FHLB restricted stock	99.0	[1]	99.1	[1]
Other fixed maturities-state deposits	257.5		251.0
Securities pledged	1,271.3	[2]	1,465.7	[2]
Total restricted assets	3,993.4		4,149.2
Securities pledged as collateral
Loss Contingencies [Line Items]
Fair value of loaned securities	449.4		435.4
Fair value of securities delivered as collateral	$ 821.9		$ 1,000.0

[1] Included in Other investments in the Condensed Consolidated Balance Sheets.

[2] Includes the fair value of loaned securities of $449.4 and $435.4 as of March 31, 2014 and December 31, 2013, respectively, which is included in Securities pledged on the Condensed Consolidated Balance Sheets. In addition, as of March 31, 2014 and December 31, 2013, the Company delivered securities as collateral of $821.9 and $1.0 billion, respectively, which was included in Securities pledged in the Condensed Consolidated Balance Sheets.