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Derivatives (Realized and Unrealized Gains (Losses) (Details) (White Mountains Life Re, USD $) In Millions, unless otherwise specified | 3 Months Ended |
--- | --- | ---
Mar. 31, 2014 | Mar. 31, 2013 | Dec. 31, 2013
Variable Annuity Reinsurance [Line Items] |  |  |
Change in fair value of variable annuity death benefit liabilities, included in other general and administrative expenses | $ 0 | $ 5.6 |
Realized and unrealized derivative gains (losses) recognized in other revenues and carrying values of instruments |  |  |
Realized and unrealized gains (losses) | (6.6) | (181.8) |
Derivative, fair value, net | 89.6 |  | 69.2
Fixed income/interest rate |  |  |
Realized and unrealized derivative gains (losses) recognized in other revenues and carrying values of instruments |  |  |
Realized and unrealized gains (losses) | (6.4) | (30.9) |
Derivative, fair value, net | (5.3) |  | (9.7)
Foreign exchange |  |  |
Realized and unrealized derivative gains (losses) recognized in other revenues and carrying values of instruments |  |  |
Realized and unrealized gains (losses) | (6.5) | (53.6) |
Derivative, fair value, net | 63.9 |  | 58.0
Equity |  |  |
Realized and unrealized derivative gains (losses) recognized in other revenues and carrying values of instruments |  |  |
Realized and unrealized gains (losses) | 6.3 | (97.3) |
Derivative, fair value, net | $ 31.0 |  | $ 20.9

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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5618551-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a),(c),(d),(e) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959 + Details
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- Definition Net increase or decrease in the fair value of the variable annuity death benefit liabilities included in earnings. + References No definition available. + Details
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