Investments (Details Textuals 31) (Subsequent payment default [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2012
Agricultural
Financing Receivable, Modifications [Line Items]
Number of Mortgage Loans	1
Carrying Value after Specific Valuation Allowance	$ 8
Commercial
Financing Receivable, Modifications [Line Items]
Number of Mortgage Loans	0
Residential
Financing Receivable, Modifications [Line Items]
Number of Mortgage Loans	0