Investments (Details 4) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Other-than-temporary impairment losses, net of recoveries
Total other-than-temporary impairment losses on available-for-sale securities	$ (49.1)	$ (40.9)	$ (82.8)	$ (54.9)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	17.1	(9.7)	22.0	(48.1)
Net impairment losses on available-for-sale securities	(32.0)	(50.6)	(60.8)	(103.0)
Fixed maturities
Other-than-temporary impairment losses, net of recoveries
Total other-than-temporary impairment losses on available-for-sale securities	(49.1)	(36.4)	(82.8)	(52.6)
Equity securities
Other-than-temporary impairment losses, net of recoveries
Total other-than-temporary impairment losses on available-for-sale securities		$ (4.5)		$ (2.3)

The amount by which the fair value of an investment in debt and equity securities categorized as Available-for-sale is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

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Before tax amount of other than temporary impairment (OTTI) on a debt security, categorized as available-for-sale, recognized in other comprehensive income (loss).

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- Definition

The amount of other than temporary impairment losses on investments in debt and equity securities categorized as Available-for-sale which have been recognized in earnings during the period. Such impairment losses consist of other than temporary impairments (OTTI) on equity securities, credit losses on investments in debt securities, and when the entity intends to sell an impaired debt security or it is more likely than not that the entity will be required to sell the impaired debt security before recovery of its amortized cost basis.

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