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Discontinued Operations (Loss from Discontinued Operations) (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended | 51 Months Ended |
--- | --- | --- | --- | ---
Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2015 | Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Net cash provided from (used for) discontinued operations |  |  |  |  |  |  |  |  | $ 14.7 | $ 60.0 | $ (61.5) |  |
Net cash provided from investing activities — discontinued operations |  |  |  |  |  |  |  |  | 31.3 | 35.8 | 148.7 |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |
Earned insurance premiums |  |  |  |  |  |  |  |  | 1,188.2 | 1,185.0 | 1,120.9 |  |
Net investment income |  |  |  |  |  |  |  |  | 60.8 | 59.5 | 59.8 |  |
Other revenue |  |  |  |  |  |  |  |  | 334.2 | 131.1 | 47.0 |  |
Net realized and unrealized investment gains |  |  |  |  |  |  |  |  | 225.4 | 78.5 | 133.9 |  |
Revenues (including realized gains and losses) | $ 678.5 | $ 334.7 | $ 403.6 | $ 391.8 | $ 405.6 | $ 323.2 | $ 393.5 | $ 331.8 | 1,808.6 | 1,454.1 | 1,361.6 |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |
Loss and loss adjustment expenses |  |  |  |  |  |  |  |  | 708.9 | 824.0 | 622.1 |  |
Insurance and reinsurance acquisition expenses |  |  |  |  |  |  |  |  | 220.1 | 206.2 | 210.4 |  |
Other underwriting expenses |  |  |  |  |  |  |  |  | 218.6 | 179.6 | 205.2 |  |
Interest expense on debt |  |  |  |  |  |  |  |  | 18.6 | 15.6 | 16.2 |  |
General and administrative expenses |  |  |  |  |  |  |  |  | 487.5 | 257.7 | 149.1 |  |
Total expenses | 420.4 | 429.3 | 412.7 | 391.3 | 471.3 | 358.7 | 359.9 | 293.2 | 1,653.7 | 1,483.1 | 1,203.0 |  |
Net income from discontinued operations, net of tax | 7.3 | $ 14.2 | $ 3.5 | $ 73.8 | 82.1 | $ 63.9 | $ 61.1 | $ 51.5 | 80.6 | 260.2 | 99.9 |  |
Gain (loss) on sale of discontinued operations, net of tax |  |  |  |  |  |  |  |  | 18.2 | (1.6) | 46.6 |  |
Change in foreign currency translation, net of tax |  |  |  |  |  |  |  |  | (65.8) | (168.5) | 2.7 |  |
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest |  |  |  |  |  |  |  |  | 197.2 | 207.3 | 247.0 |  |
Net cash (used for) provided from financing activities — discontinued operations |  |  |  |  |  |  |  |  | (9.1) | (63.2) | (87.5) |  |
Cash and Cash Equivalents, at Carrying Value | 173.5 |  |  |  | 238.0 |  |  |  | 173.5 | 238.0 | 233.5 | $ 173.5 | $ 118.9
Discontinued Operations |  |  |  |  |  |  |  |  |  |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |
Net cash provided from (used for) discontinued operations |  |  |  |  |  |  |  |  | 14.7 | 60.0 | (61.5) |  |
Net cash provided from investing activities — discontinued operations |  |  |  |  |  |  |  |  | 31.3 | 35.8 | 148.7 |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |
Earned insurance premiums |  |  |  |  |  |  |  |  | 847.0 | 874.0 | 867.2 |  |
Net investment income |  |  |  |  |  |  |  |  | 40.7 | 40.9 | 46.7 |  |
Other revenue |  |  |  |  |  |  |  |  | (21.3) | (62.4) | 27.6 |  |
Net realized and unrealized investment gains |  |  |  |  |  |  |  |  | 15.1 | 205.4 | 27.8 |  |
Revenues (including realized gains and losses) |  |  |  |  |  |  |  |  | 881.5 | 1,057.9 | 969.3 |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |
Loss and loss adjustment expenses |  |  |  |  |  |  |  |  | 422.7 | 344.6 | 497.3 |  |
Insurance and reinsurance acquisition expenses |  |  |  |  |  |  |  |  | 189.8 | 193.7 | 166.5 |  |
Other underwriting expenses |  |  |  |  |  |  |  |  | 107.9 | 133.2 | 125.9 |  |
Interest expense on debt |  |  |  |  |  |  |  |  | 26.6 | 26.3 | 26.3 |  |
General and administrative expenses |  |  |  |  |  |  |  |  | 27.0 | 30.5 | 32.2 |  |
Total expenses |  |  |  |  |  |  |  |  | 774.0 | 728.3 | 848.2 |  |
Net income (loss) from discontinued operations |  |  |  |  |  |  |  |  | 107.5 | 329.6 | 121.1 |  |
Income tax expense |  |  |  |  |  |  |  |  | (26.9) | (69.4) | (21.2) |  |
Net income from discontinued operations, net of tax |  |  |  |  |  |  |  |  | 80.6 | 260.2 | 99.9 |  |
Gain (loss) on sale of discontinued operations, net of tax |  |  |  |  |  |  |  |  |  |  | 46.6 |  |
Total income from discontinued operations |  |  |  |  |  |  |  |  | 98.8 | 258.6 | 146.5 |  |
Change in foreign currency translation, net of tax |  |  |  |  |  |  |  |  |  | (169.5) | 6.1 |  |
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest |  |  |  |  |  |  |  |  | 33.8 | 89.1 | 152.6 |  |
Net cash (used for) provided from financing activities — discontinued operations |  |  |  |  |  |  |  |  | (9.1) | (63.2) | (87.5) |  |
Effect of Exchange Rate on Cash |  |  |  |  |  |  |  |  | (4.5) | (14.3) | (0.2) |  |
Net Cash Provided by (Used in) Discontinued Operations |  |  |  |  |  |  |  |  | 32.4 | 18.3 | (0.5) |  |
Cash and Cash Equivalents, at Carrying Value | $ 143.9 |  |  |  | $ 111.5 |  |  |  | 143.9 | 111.5 | 93.2 | 143.9 | $ 93.7
Sirius Group |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |
Net investment income |  |  |  |  |  |  |  |  | 225.0 | 4.0 | 1.0 |  |
Net realized and unrealized investment gains |  |  |  |  |  |  |  |  | 225.0 | 4.0 | 1.0 |  |
Sirius Group | Discontinued Operations |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |
Earned insurance premiums |  |  |  |  |  |  |  |  | 847.0 | 873.9 | 866.4 |  |
Net investment income |  |  |  |  |  |  |  |  | 40.7 | 40.9 | 46.7 |  |
Other revenue |  |  |  |  |  |  |  |  | (20.6) | (62.4) | 16.8 |  |
Net realized and unrealized investment gains |  |  |  |  |  |  |  |  | 15.1 | 205.4 | 27.8 |  |
Revenues (including realized gains and losses) |  |  |  |  |  |  |  |  | 882.2 | 1,057.8 | 957.7 |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |
Loss and loss adjustment expenses |  |  |  |  |  |  |  |  | 422.7 | 345.3 | 418.4 |  |
Insurance and reinsurance acquisition expenses |  |  |  |  |  |  |  |  | 189.8 | 193.6 | 166.5 |  |
Other underwriting expenses |  |  |  |  |  |  |  |  | 107.9 | 129.7 | 126.1 |  |
Interest expense on debt |  |  |  |  |  |  |  |  | 26.6 | 26.3 | 26.3 |  |
General and administrative expenses |  |  |  |  |  |  |  |  | 27.0 | 30.5 | 32.2 |  |
Total expenses |  |  |  |  |  |  |  |  | 774.0 | 725.4 | 769.5 |  |
Net income (loss) from discontinued operations |  |  |  |  |  |  |  |  | 108.2 | 332.4 | 188.2 |  |
Income tax expense |  |  |  |  |  |  |  |  | 27.1 | 70.4 | 46.2 |  |
Net income from discontinued operations, net of tax |  |  |  |  |  |  |  |  | 81.1 | 262.0 | 142.0 |  |
Gain (loss) on sale of discontinued operations, net of tax |  |  |  |  |  |  |  |  |  |  | 0.0 |  |
Total income from discontinued operations |  |  |  |  |  |  |  |  | 81.1 | 262.0 | 142.0 |  |
Change in foreign currency translation, net of tax |  |  |  |  |  |  |  |  | (65.0) | (169.5) | 6.1 |  |
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest |  |  |  |  |  |  |  |  | 16.1 | 92.5 | 148.1 |  |
Other Operations | Discontinued Operations |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |
Earned insurance premiums |  |  |  |  |  |  |  |  | 0.0 | 0.1 | 0.8 |  |
Net investment income |  |  |  |  |  |  |  |  | 0.0 | 0.0 | 0.0 |  |
Other revenue |  |  |  |  |  |  |  |  | (0.7) | 0.0 | 10.8 |  |
Net realized and unrealized investment gains |  |  |  |  |  |  |  |  | 0.0 | 0.0 | 0.0 |  |
Revenues (including realized gains and losses) |  |  |  |  |  |  |  |  | (0.7) | 0.1 | 11.6 |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |
Loss and loss adjustment expenses |  |  |  |  |  |  |  |  | 0.0 | (0.7) | 78.9 |  |
Insurance and reinsurance acquisition expenses |  |  |  |  |  |  |  |  | 0.0 | 0.1 | 0.0 |  |
Other underwriting expenses |  |  |  |  |  |  |  |  | 0.0 | 3.5 | (0.2) |  |
Interest expense on debt |  |  |  |  |  |  |  |  | 0.0 | 0.0 | 0.0 |  |
General and administrative expenses |  |  |  |  |  |  |  |  | 0.0 | 0.0 | 0.0 |  |
Total expenses |  |  |  |  |  |  |  |  | 0.0 | 2.9 | 78.7 |  |
Net income (loss) from discontinued operations |  |  |  |  |  |  |  |  | (0.7) | (2.8) | (67.1) |  |
Income tax expense |  |  |  |  |  |  |  |  | (0.2) | (1.0) | (25.0) |  |
Net income from discontinued operations, net of tax |  |  |  |  |  |  |  |  | (0.5) | (1.8) | (42.1) |  |
Total income from discontinued operations |  |  |  |  |  |  |  |  | 17.7 | (3.4) | 4.5 |  |
Change in foreign currency translation, net of tax |  |  |  |  |  |  |  |  | (65.0) | 0.0 | 0.0 |  |
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest |  |  |  |  |  |  |  |  | 17.7 | (3.4) | 4.5 |  |
Fireman's Fund Insurance Company [Member] | Discontinued Operations |  |  |  |  |  |  |  |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on sale of discontinued operations, net of tax |  |  |  |  |  |  |  |  |  | 14.0 |  |  |
OneBeacon Runoff | Discontinued Operations |  |  |  |  |  |  |  |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (loss) on sale of discontinued operations, net of tax |  |  |  |  |  |  |  |  | 0.3 | (18.8) | 46.6 |  |
Esurance [Member] | Discontinued Operations |  |  |  |  |  |  |  |  |  |  |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |
Net income from discontinued operations, net of tax |  |  |  |  |  |  |  |  |  |  | 4.5 |  |
Gain (loss) on sale of discontinued operations, net of tax |  |  |  |  |  |  |  |  | 17.9 | 3.2 |  | $ 28.3 |
Other Segments |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |
Earned insurance premiums |  |  |  |  |  |  |  |  | 8.7 | 6.1 | 0.0 |  |
Net investment income |  |  |  |  |  |  |  |  | 8.8 | 9.0 | 11.1 |  |
Other revenue |  |  |  |  |  |  |  |  | 334.1 | 124.7 | 15.4 |  |
Net realized and unrealized investment gains |  |  |  |  |  |  |  |  | 259.9 | 29.8 | 95.8 |  |
Revenues (including realized gains and losses) |  |  |  |  |  |  |  |  | 611.5 | 169.6 | 122.3 |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |
Loss and loss adjustment expenses |  |  |  |  |  |  |  |  | 8.2 | 8.9 | 0.0 |  |
Insurance and reinsurance acquisition expenses |  |  |  |  |  |  |  |  | 3.4 | 0.8 | 0.0 |  |
Other underwriting expenses |  |  |  |  |  |  |  |  | 0.0 | 0.0 | 0.0 |  |
Interest expense on debt |  |  |  |  |  |  |  |  | 5.6 | 2.6 | 3.2 |  |
Total expenses |  |  |  |  |  |  |  |  | 452.5 | 218.7 | $ 106.4 |  |
Symetra | Sirius Group |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |
Net realized and unrealized investment gains |  |  |  |  |  |  |  |  | 218.5 |  |  |  |
Symetra | Other Segments |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |
Net realized and unrealized investment gains |  |  |  |  |  |  |  |  | 258.8 |  |  |  |
Tranzact [Member] | Other Segments |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |
Other revenue |  |  |  |  |  |  |  |  | 186.9 | 43.2 |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |
General and administrative expenses |  |  |  |  |  |  |  |  | 167.3 | 37.4 |  |  |
MediaAlpha [Member] | Other Segments |  |  |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  |  |  |
Other revenue |  |  |  |  |  |  |  |  | 105.5 | 65.3 |  |  |
Expenses |  |  |  |  |  |  |  |  |  |  |  |  |
General and administrative expenses |  |  |  |  |  |  |  |  | $ 99.0 | $ 60.6 |  |  |

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