Schedule of Net Unrealized Gain on Securities (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in Components of Net Unrealized Gain on Securities
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	$ (2,101.2)	$ 918.8	$ 1,519.8
Fixed Maturity Securities
Change in Components of Net Unrealized Gain on Securities
Balance, Beginning of Period, Net of Tax	7,221.5
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(3,166.7)
Balance, End of Period, Net of Tax	4,054.8
Other Investments
Change in Components of Net Unrealized Gain on Securities
Balance, Beginning of Period, Net of Tax	92.8
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(37.3)
Balance, End of Period, Net of Tax	55.5
Deferred Acquisition Costs
Change in Components of Net Unrealized Gain on Securities
Balance, Beginning of Period, Net of Tax	(67.0)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	25.4
Balance, End of Period, Net of Tax	(41.6)
Reserve for Future Policy and Contract Benefits
Change in Components of Net Unrealized Gain on Securities
Balance, Beginning of Period, Net of Tax	(6,277.5)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	2,169.0
Balance, End of Period, Net of Tax	(4,108.5)
Reinsurance Recoverable
Change in Components of Net Unrealized Gain on Securities
Balance, Beginning of Period, Net of Tax	351.5
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(87.7)
Balance, End of Period, Net of Tax	263.8
Deferred Income Tax Charges
Change in Components of Net Unrealized Gain on Securities
Balance, Beginning of Period, Net of Tax	(447.8)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	359.5
Balance, End of Period, Net of Tax	(88.3)
Net Unrealized Gain on Securities
Change in Components of Net Unrealized Gain on Securities
Balance, Beginning of Period, Net of Tax	873.5
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(737.8)
Balance, End of Period, Net of Tax	$ 135.7