Summary of Significant Accounting Policies (Details Textual) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Accounting Pronouncements Not Yet Adopted (Textual) [Abstract]
Expected minimum percentage reduction of deferred policy acquisition costs due to the adoption of new accounting guidance	22.00%
Expected maximum percentage reduction of deferred policy acquisition costs due to the adoption of new accounting guidance	27.00%
Expected minimum reduction to shareholders' equity due to the adoption of new accounting guidance	$ 250
Expected maximum reduction to shareholders' equity due to the adoption of new accounting guidance	$ 300