Schedule of Net Unrealized Gain on Securities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				3 Months Ended		3 Months Ended		3 Months Ended		3 Months Ended		3 Months Ended		3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Debt Securities [Member]	Dec. 31, 2012 Debt Securities [Member]	Mar. 31, 2013 Other Investments [Member]	Dec. 31, 2012 Other Investments [Member]	Mar. 31, 2013 Deferred Acquisition Costs [Member]	Dec. 31, 2012 Deferred Acquisition Costs [Member]	Mar. 31, 2013 Reserve for Future Policy and Contract Benefits [Member]	Dec. 31, 2012 Reserve for Future Policy and Contract Benefits [Member]	Mar. 31, 2013 Reinsurance Recoverable [Member]	Dec. 31, 2012 Reinsurance Recoverable [Member]	Mar. 31, 2013 Deferred Income Tax Charges [Member]	Dec. 31, 2012 Deferred Income Tax Charges [Member]	Mar. 31, 2013 Includes Unrealized Adjustment for Deferred Policy Acquisition Costs and Reserves for Future Policy and Contract Benefits [Member]	Dec. 31, 2012 Includes Unrealized Adjustment for Deferred Policy Acquisition Costs and Reserves for Future Policy and Contract Benefits [Member]
Schedule of Net Unrealized Gain on Securities [Line Items]
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax			$ 6,803.9	$ 7,221.5	$ 72.5	$ 92.8	$ (61.2)	$ (67.0)	$ (5,979.7)	$ (6,277.5)	$ 353.9	$ 351.5	$ (397.0)	$ (447.8)	$ 792.4	$ 873.5
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	$ (278.5)	$ (197.2)	$ (417.6)		$ (20.3)		$ 5.8		$ 297.8		$ 2.4		$ 50.8		$ (81.1)