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Common Shareholders’ Equity and Non-controlling Interests Common Shareholders’ Equity and Non-controlling Interests (Tables) | 12 Months Ended
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Dec. 31, 2017
Noncontrolling Interest [Abstract] |
Noncontrolling Interest | The following table presents the balance of non-controlling interests included in White Mountains’s total equity and the related percentage of each consolidated entity’s total equity owned by non-controlling shareholders as of December 31, 2017 and 2016:
|  | December 31, 2017 |  | December 31, 2016
$ in millions |  | Non-controlling Percentage |  | Non-controlling Equity |  | Non-controlling Percentage |  | Non-controlling Equity
OneBeacon |  | — | % |  | $ | — |  |  | 23.9 | % |  | $ | 244.6 |
Other, excluding mutuals and reciprocals |  |  |  |  |  |  |  |
HG Global |  | 3.1 |  |  | 15.9 |  |  | 3.1 |  |  | 16.6 |
MediaAlpha |  | 35.7 |  |  | 13.1 |  |  | 40.0 |  |  | 11.7 |
Dewar (1) |  | — |  |  | — |  |  | 18.8 |  |  | 3.9 |
Buzzmove |  | 22.9 |  |  | 2.5 |  |  | 29.1 |  |  | 3.0 |
Total other, excluding mutuals and reciprocals |  |  |  | 31.5 |  |  |  |  | 35.2 |
Mutuals and reciprocals |  |  |  |  |  |  |  |
BAM |  | 100.0 |  |  | (163.2 | ) |  | 100.0 |  |  | (150.9 | )
SSIE |  | — |  |  | — |  |  | 100.0 |  |  | 4.4 |
Total mutuals and reciprocals |  |  |  | (163.2 | ) |  |  |  | (146.5 | )
Total non-controlling interests |  |  |  | $ | (131.7 | ) |  |  |  | $ | 133.3 |
(1) Dewar is a subsidiary of OneBeacon.

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- Definition Tabular disclosure of redeemable noncontrolling interest (as defined) included in the statement of financial position as either a liability or temporary equity. As of the date of the statement of financial position, such redeemable noncontrolling interest is currently redeemable, as defined, for cash or other assets of the entity at (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the entity. + References No definition available. + Details
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