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Investments in Unconsolidated Affiliates (Details) (USD $) In Millions | Sep. 30, 2011 | Jun. 30, 2011 | Dec. 31, 2010 | Sep. 30, 2010 | Jun. 30, 2010 | Dec. 31, 2009
--- | --- | --- | --- | --- | --- | ---
Investments in unconsolidated affiliates |  |  |  |  |  |
Total investments in unconsolidated affiliates | $ 458.6 |  | $ 389.7 |  |  |
Symetra |  |  |  |  |  |
Investments in unconsolidated affiliates |  |  |  |  |  |
Total investments in unconsolidated affiliates | 456.7 | 421.0 | 387.5 | 416.1 | 372.5 | 307.7
Symetra | Common shareholders' equity |  |  |  |  |  |
Investments in unconsolidated affiliates |  |  |  |  |  |
Total investments in unconsolidated affiliates | 449.0 | 388.5 | 350.4 | 399.2 | 344.9 | 269.2
Symetra | Warrants |  |  |  |  |  |
Investments in unconsolidated affiliates |  |  |  |  |  |
Total investments in unconsolidated affiliates | 7.7 | 32.5 | 37.1 | 16.9 | 27.6 | 38.5
Pentelia Capital Management |  |  |  |  |  |
Investments in unconsolidated affiliates |  |  |  |  |  |
Total investments in unconsolidated affiliates | $ 1.9 |  | $ 2.2 |  |  |

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