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Derivatives (Realized and Unrealized Gains (Losses) (Details) (White Mountains Life Re, USD $) In Millions, unless otherwise specified | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2014 | Jun. 30, 2013 | Jun. 30, 2014 | Jun. 30, 2013 | Dec. 31, 2013
Realized and unrealized derivative gains (losses) recognized in other revenues and carrying values of instruments |  |  |  |  |
Realized and unrealized gains (losses) | $ (26.2) | $ (63.5) | $ (32.7) | $ (245.3) |
Derivative, fair value, net | 74.8 |  | 74.8 |  | 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) | (5.6) | (8.5) | (12.0) | (39.3) |
Derivative, fair value, net | (3.3) |  | (3.3) |  | (9.7)
Foreign exchange |  |  |  |  |
Realized and unrealized derivative gains (losses) recognized in other revenues and carrying values of instruments |  |  |  |  |
Realized and unrealized gains (losses) | (6.4) | (22.0) | (12.9) | (75.6) |
Derivative, fair value, net | 58.2 |  | 58.2 |  | 58.0
Equity |  |  |  |  |
Realized and unrealized derivative gains (losses) recognized in other revenues and carrying values of instruments |  |  |  |  |
Realized and unrealized gains (losses) | (14.2) | (33.0) | (7.8) | (130.4) |
Derivative, fair value, net | $ 19.9 |  | $ 19.9 |  | $ 20.9

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- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13433-108611 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13495-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 + Details
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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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