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Investments in Unconsolidated Affiliates (Symetra) (Details) (USD $) In Millions, except Share data, unless otherwise specified | 3 Months Ended | 6 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Jun. 30, 2013 | Jun. 30, 2012 | Jun. 20, 2013 | Jun. 30, 2013 | Jun. 30, 2012 | Dec. 31, 2011 | Dec. 31, 2012
Investments in unconsolidated affiliates |  |  |  |  |  |  |
Common shares received from exercised warrants |  |  | $ 2.65 |  |  |  |
Average price per share | $ 600.00 | $ 508.00 |  | $ 564.00 | $ 497.00 |  |
Symetra |  |  |  |  |  |  |
Investments in unconsolidated affiliates |  |  |  |  |  |  |
Shares of Symetra Financial Corporation owned (in shares) | 20,050,000 |  |  | 20,050,000 |  |  | 17,400,000
Ownership interest (as a percent) | 17.00% |  |  | 17.00% |  |  | 15.00%
Investments in unconsolidated affiliates on conversion of warrants | 9,490,000 |  | 9,490,000 | 9,490,000 |  |  |
Unamortized basis difference |  |  | 19.3 |  |  |  |
Fair value of investment |  |  |  |  |  | 261.0 |
Estimated fair value of investment per share |  |  |  |  |  | $ 15 |
Impairment of Common Shares Equity in Earnings after Tax |  |  |  |  |  | 45.9 |
Equity in net unrealized losses increase relating to amortization of common share impairment |  |  |  |  |  | 136.6 |
Term of amortization (in years) |  |  |  | 30 years |  |  |
After tax amortization through equity in earnings | 0.7 |  |  | 1.4 |  |  |
After tax amortization through equity in net unrealized losses | 2.5 |  |  | 5.0 |  |  |
Pre-tax unamortized basis difference | 191.5 |  |  | 191.5 |  |  |
Gain (Loss) on Warrants | 14.5 | 6.1 |  | 10.8 | 17.2 |  |
Risk free interest rate (as a percent) |  |  | 0.34% |  |  |  |
Volatility rate (as a percent) |  |  | 26.50% |  |  |  |
Expected life (in years) |  |  | 1 year 1 month 10 days |  |  |  |
Class of warrant or right fair value assumptions per strike price |  |  | $ 11.49 |  |  |  |
Market Price Per Share | $ 15.99 |  | $ 15.53 | $ 15.99 |  |  |
Proceeds from Equity Method Investment, Dividends or Distributions | (1.4) | (1.2) |  | (2.8) | (2.4) |  |
Common Stock | Symetra |  |  |  |  |  |  |
Investments in unconsolidated affiliates |  |  |  |  |  |  |
Equity in net unrealized losses increase relating to amortization of common share impairment | 2.8 | 3.3 |  | 5.5 | 6.6 |  |
Gain (Loss) on Warrants | 0 | 0 |  | 0 | 0 |  |
Proceeds from Equity Method Investment, Dividends or Distributions | (1.4) | (1.2) |  | (2.8) | (2.4) |  |
Warrants | Symetra |  |  |  |  |  |  |
Investments in unconsolidated affiliates |  |  |  |  |  |  |
Gain (Loss) on Warrants | 14.5 | 6.1 |  | 10.8 | 17.2 |  |
Proceeds from Equity Method Investment, Dividends or Distributions | 0 | 0 |  | 0 | 0 |  |
Proceeds from Dividends Received | 0.7 |  |  | 1.5 |  |  |
Symetra |  |  |  |  |  |  |
Investments in unconsolidated affiliates |  |  |  |  |  |  |
Stock Repurchased and Retired During Period, Shares |  |  |  | 6,600,000 |  |  |
Average price per share |  |  | $ 13.44 |  |  |  |
Income (Loss) from Equity Method Investments [Member] | Symetra |  |  |  |  |  |  |
Investments in unconsolidated affiliates |  |  |  |  |  |  |
Unamortized basis difference |  |  | 0.4 |  |  |  |
Pre-tax unamortized basis difference | 40.5 |  |  | 40.5 |  |  |
Net unrealized gains (losses) of unconsolidated affiliates [Member] | Symetra |  |  |  |  |  |  |
Investments in unconsolidated affiliates |  |  |  |  |  |  |
Unamortized basis difference |  |  | 18.9 |  |  |  |
Pre-tax unamortized basis difference | $ 151.0 |  |  | $ 151.0 |  |  |

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