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SCHEDULE II CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT - Statement of Operations and Comprehensive Income (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Dec. 31, 2019 | Sep. 30, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Sep. 30, 2018 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT |  |  |  |  |  |  |  |  |  |  |  |
Revenues (loss) (including realized and unrealized gains and losses) | $ 175.3 | $ 155.5 | $ 129.0 | $ 433.6 | $ 6.0 | $ 198.7 | $ 122.3 | $ 42.1 |  | $ 893.4 | $ 369.1 | $ 373.8
Expenses | 118.8 | 104.4 | 113.2 | 151.9 | 150.1 | 154.4 | 134.7 | 108.1 |  | 488.3 | 547.3 | 366.0
Pre-tax income (loss) | 56.5 | 51.1 | 15.8 | 281.7 | (144.1) | 44.3 | (12.4) | (66.0) |  | 405.1 | (178.2) | 7.8
Income tax (expense) benefit | (10.4) | (8.8) | 0.1 | (10.2) | 3.6 | 3.6 | (2.5) | (0.7) |  | (29.3) | 4.0 | 7.8
Net income (loss) from continuing operations | 46.1 | 42.3 | 15.9 | 271.5 | (140.5) | 47.9 | (14.9) | (66.7) |  | 375.8 | (174.2) | 15.6
Net income from discontinued operations, net of tax | (0.8) | 0.9 | 0.0 | 0.7 | 0.0 | (17.3) | 0.0 | 0.1 |  | 0.0 | 0.0 | 20.5
Net loss attributable to non-controlling interests | 15.6 | 5.5 | 4.6 | 12.2 | 3.0 | 10.2 | 18.4 | 18.6 |  | 37.9 | 50.2 | 34.1
Net income (loss) attributable to White Mountains’s common shareholders | $ 60.9 | $ 48.7 | $ 20.5 | $ 284.4 | $ (137.5) | $ 40.8 | $ 3.5 | $ (48.0) |  | 414.5 | (141.2) | 627.2
Other comprehensive (loss) income, net of tax |  |  |  |  |  |  |  |  |  | (1.4) | (4.8) | 0.3
Comprehensive income (loss) attributable to White Mountains’s common shareholders |  |  |  |  |  |  |  |  |  | 413.1 | (145.7) | 630.5
Total income (loss) from discontinued operations |  |  |  |  |  |  |  |  |  | 0.8 | (17.2) | 577.5
White Mountains Insurance Group Ltd. |  |  |  |  |  |  |  |  |  |  |  |
CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT |  |  |  |  |  |  |  |  |  |  |  |
Revenues (loss) (including realized and unrealized gains and losses) |  |  |  |  |  |  |  |  |  | 65.0 | (47.7) | 27.3
Expenses |  |  |  |  |  |  |  |  |  | 47.1 | 45.9 | 99.7
Pre-tax income (loss) |  |  |  |  |  |  |  |  |  | 17.9 | (93.6) | (72.4)
Income tax (expense) benefit |  |  |  |  |  |  |  |  |  | 0.9 | 2.5 | 1.4
Net income (loss) from continuing operations |  |  |  |  |  |  |  |  |  | 17.0 | (96.1) | (73.8)
Net income from discontinued operations, net of tax |  |  |  |  |  |  |  |  |  | 0.8 | (17.2) | 0.0
Equity in earnings of unconsolidated affiliates |  |  |  |  |  |  |  |  |  | 398.5 | (27.4) | 701.0
Net loss attributable to non-controlling interests |  |  |  |  |  |  |  |  |  | (1.8) | (0.5) | 0.0
Net income (loss) attributable to White Mountains’s common shareholders |  |  |  |  |  |  |  |  |  | 414.5 | (141.2) | 627.2
Other comprehensive (loss) income, net of tax |  |  |  |  |  |  |  |  |  | (1.4) | (4.5) | 3.3
Comprehensive income (loss) attributable to White Mountains’s common shareholders |  |  |  |  |  |  |  |  |  | 413.1 | (145.7) | 630.5
Discontinued Operations |  |  |  |  |  |  |  |  |  |  |  |
CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT |  |  |  |  |  |  |  |  |  |  |  |
Net income (loss) attributable to White Mountains’s common shareholders |  |  |  |  |  |  |  |  |  | 414.5 | (141.2) | 627.2
Total income (loss) from discontinued operations |  |  |  |  |  |  |  |  |  | 0.8 | (17.2) | 577.5
Discontinued Operations | Sirius Group |  |  |  |  |  |  |  |  |  |  |  |
CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT |  |  |  |  |  |  |  |  |  |  |  |
Revenues (loss) (including realized and unrealized gains and losses) |  |  |  |  |  |  |  |  |  |  |  | 0.0
Expenses |  |  |  |  |  |  |  |  |  |  |  | 0.0
Net income from discontinued operations, net of tax |  |  |  |  |  |  |  |  |  |  |  | 0.0
Total income (loss) from discontinued operations |  |  |  |  |  |  |  |  |  |  |  | (0.7)
Discontinued Operations | OneBeacon, Sirius Group, and Tranzact |  |  |  |  |  |  |  |  |  |  |  |
CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT |  |  |  |  |  |  |  |  |  |  |  |
Total income (loss) from discontinued operations |  |  |  |  |  |  |  |  |  |  |  | $ 577.5
Swedish Tax Authority | Sirius Group | Sirius Group |  |  |  |  |  |  |  |  |  |  |  |
CONDENSED FINANCIAL INFORMATION OF THE REGISTRANT |  |  |  |  |  |  |  |  |  |  |  |
Net income from discontinued operations, net of tax |  |  |  |  |  |  |  |  | $ (17.3) | 0.8 |  |
Loss contingency accrual, period increase (decrease) |  |  |  |  |  |  |  |  |  | $ (0.8) | $ 17.3 |

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