Nature of Operations and Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			6 Months Ended		12 Months Ended		1 Months Ended
	Dec. 31, 2010 Effects of implementation of accounting change related to variable interest entities, net Retained earnings (deficit)	Dec. 31, 2010 Effects of implementation of accounting change related to variable interest entities, net Accumulated other comprehensive income (loss)	Jul. 31, 2010 Effects of electing fair value option for fixed maturities upon implementation of accounting change related to embedded credit derivatives, net	Dec. 31, 2010 Effects of electing fair value option for fixed maturities upon implementation of accounting change related to embedded credit derivatives, net Retained earnings (deficit)	Dec. 31, 2010 Effects of electing fair value option for fixed maturities upon implementation of accounting change related to embedded credit derivatives, net Accumulated other comprehensive income (loss)	Dec. 31, 2009 Effects of reclassifying noncredit component of previously recognized impairment losses on fixed maturities, available-for-sale, net Retained earnings (deficit)	Dec. 31, 2009 Effects of reclassifying noncredit component of previously recognized impairment losses on fixed maturities, available-for-sale, net Accumulated other comprehensive income (loss)	Jan. 31, 2012 Effects of implementation of accounting change related to deferred policy acquisition costs, net Retained earnings (deficit)
Recent Accounting Pronouncements Disclosures
Cumulative effect of adoption of new accounting principle, increase (decrease) in equity account	$ (10.7)	$ 10.7		$ (25.4)	$ 25.4	$ 9.9	$ (9.9)	$ (640.0)
Fair value of fixed maturities reclassified from available-for-sale to trading			$ 75.3