Investments Impaired Loans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Investments, Debt and Equity Securities [Abstract]
Impaired loans, average investment during the period			$ 0		$ 8.3
Interest income recognized on impaired loans, on an accural basis	0	0	0	0
Interest income recognized on impaired loans, on a cash basis	$ 0	$ 0	$ 0	$ 0.1