Derivative Financial Instruments (Notional Amounts, Balance Sheet Location And Estimated Fair Values Of Derivative Financial Instruments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivative [Line Items]
Contractual Notional Amount	$ 9,919.2	$ 8,296.5
Total derivative assets	901.9	513.5
Amounts netted	(791.8)	(418.9)
Net derivative assets	110.1	94.6
Total derivative liabilities	(812.5)	(419.0)
Amounts netted	791.8	418.9
Net derivative liabilities	(20.7)	(0.1)
Hedging Instruments [Member] | Other Assets/Other Liabilities | Interest Rate Swaps [Member]
Derivative [Line Items]
Contractual Notional Amount	1,660.0	1,650.0
Total derivative assets	30.9	58.6
Total derivative liabilities	(20.7)	(0.1)
Non-Hedging Instruments [Member]
Derivative [Line Items]
Contractual Notional Amount	8,259.2	6,646.5
Total derivative assets	871.0	454.9
Total derivative liabilities	(791.8)	(418.9)
Non-Hedging Instruments [Member] | Fixed Maturity Securities [Member] | Derivatives Embedded In Convertible Securities [Member]
Derivative [Line Items]
Contractual Notional Amount	295.0	278.8
Total derivative assets	89.2	67.2
Total derivative liabilities	0	0
Non-Hedging Instruments [Member] | Equity Securities [Member] | Interest Rate Swaps [Member]
Derivative [Line Items]
Contractual Notional Amount	72.6
Total derivative assets	1.8
Total derivative liabilities	(2.5)
Non-Hedging Instruments [Member] | Equity Securities [Member] | Credit Default And Interest Rate Swaps [Member]
Derivative [Line Items]
Contractual Notional Amount		95.9
Total derivative assets		0
Total derivative liabilities		(7.3)
Non-Hedging Instruments [Member] | Equity Securities [Member] | Options [Member]
Derivative [Line Items]
Contractual Notional Amount		6,271.8
Total derivative assets		385.6
Total derivative liabilities		(411.2)
Non-Hedging Instruments [Member] | Equity Securities [Member] | Futures [Member]
Derivative [Line Items]
Contractual Notional Amount	0	0
Total derivative assets	3.5	2.1
Total derivative liabilities	(1.6)	(0.4)
Non-Hedging Instruments [Member] | Equity Securities and Other Assets [Member] | Options [Member]
Derivative [Line Items]
Contractual Notional Amount	7,891.6
Total derivative assets	776.5
Total derivative liabilities	$ (787.7)