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Investments in Unconsolidated Affiliates (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Investments in unconsolidated affiliates
Total investments in unconsolidated affiliates	$ 294.9	$ 275.3
Symetra
Investments in unconsolidated affiliates
Total investments in unconsolidated affiliates	293.2	273.6	392.8	387.5
Symetra | Common shareholders' equity.
Investments in unconsolidated affiliates
Total investments in unconsolidated affiliates	269.5	261.0	356.9	350.4
Symetra | Warrants
Investments in unconsolidated affiliates
Total investments in unconsolidated affiliates	23.7	12.6	35.9	37.1
Pentelia Capital Management
Investments in unconsolidated affiliates
Total investments in unconsolidated affiliates	$ 1.7	$ 1.7

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- Definition

Total investments in (A) companies that are accounted for using the equity method and (B) warrants to acquire additional shares of an unconsolidated affiliate that are carried at fair value.

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