Derivative Financial Instruments (Effect Of Non-Hedging Derivatives On Income Statement And Included In Net Realized Gains (Losses) On Financial Instruments) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) Recognized	$ (3.9)	$ 7.0	$ (222.6)	$ 7.1
Derivatives Embedded In Convertible Fixed Maturity Securities | Net realized gains (losses) on financial instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) Recognized		0.8		(21.5)
Interest Rate Swaps [Member] | Net realized gains (losses) on financial instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) Recognized	2.8	(8.8)	(23.5)	(5.7)
Options [Member] | Net realized gains (losses) on financial instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) Recognized	(7.7)	18.0	(197.8)	34.4
Futures [Member] | Net realized gains (losses) on financial instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) Recognized	$ 1.0	$ (3.0)	$ (1.3)	$ (0.1)