13. Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accumulated Other Comprehensive Income (Loss), beginning balance	$ 11.4	$ 2.6	$ (12.9)
Change in component during the year	8.8	15.5
Accumulated Other Comprehensive Income (Loss), ending balance	11.4	2.6	(12.9)
Net Unrealized Investment Losses [Member]
Accumulated Other Comprehensive Income (Loss), beginning balance	25.3	25.9	6.5
Change in component during the year	(0.6)	19.4
Accumulated Other Comprehensive Income (Loss), ending balance	25.3	25.9	6.5
Portion of OTTI Losses Recognized in OCI [Member]
Accumulated Other Comprehensive Income (Loss), beginning balance	(13.9)	(23.3)	(19.4)
Change in component during the year	9.4	(3.9)
Accumulated Other Comprehensive Income (Loss), ending balance	$ (13.9)	$ (23.3)	$ (19.4)