Debt (Details 2) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Long-Term Debt
Long-term debt	$ 1,564.8	$ 1,583.7
7.875% notes payable, due 2014
Long-Term Debt
Long-term debt	400.0	400.0
3.76% notes payable, due 2015
Long-Term Debt
Long-term debt	89.9	102.8
8.875% notes payable, due 2019
Long-Term Debt
Long-term debt	350.0	350.0
6.05% notes payable, due 2036
Long-Term Debt
Long-term debt	601.7	601.7
8% surplus notes payable, due 2044
Long-Term Debt
Long-term debt	99.3	99.3
Non-recourse mortgages and notes payable
Long-Term Debt
Long-term debt	23.9	29.5
Other mortgages and notes payable
Long-Term Debt
Long-term debt		$ 0.4