Commitments and Contingencies (Restricted Assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Commitments and Contingencies Disclosure [Abstract]
Other fixed maturities-state deposits	$ 13.4		$ 13.6
Securities pledged	219.7	[1]	593.7	[1]
Total restricted assets	233.1		607.3
Fair value of loaned securities	$ 180.2		$ 515.8

[1] Includes the fair value of loaned securities of $180.2 and $515.8 as of December 31, 2012 and 2011, respectively, which is included in Securities pledged on the Consolidated Balance Sheets.