Investments (Amortized Cost And Fair Value Of Fixed Maturity Securities, By Contractual Maturity) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Amortized Cost
Available For Sale Securities Amortized Cost	$ 18,478.5	$ 17,356.1
Fixed Maturity Securities [Member]
Amortized Cost
Due in one year or less, Amortized Cost	423.9
Due after one year through five years, Amortized Cost	4,580.5
Due after five years through ten years, Amortized Cost	5,105.4
Due after ten years, Amortized Cost	4,424.4
Mortgage-backed securities, Amortized Cost	2,748.4
Available For Sale Securities Amortized Cost	17,282.6	16,459.1
Fair Value
Due in one year or less, Estimated Fair Value	426.3
Due after one year through five years, Estimated Fair Value	4,712.1
Due after five years through ten years, Estimated Fair Value	5,196.6
Due after ten years, Estimated Fair Value	4,397.6
Mortgage-backed securities, Estimated Fair Value	2,755.5
Available for sale securities Fair Value	$ 17,488.1

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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