XML 94 R114.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Derivatives Derivatives (Gross Asset (Gross liability) Amounts Offset Under Master Netting Agreements) (Details) (White Mountains Life Re, USD $) In Millions, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013
--- | --- | ---
Derivative [Line Items] |  |
Derivative Asset | $ 64.4 us-gaap_DerivativeAssets | $ 106.0 us-gaap_DerivativeAssets
Derivative Liability | (8.0)us-gaap_DerivativeLiabilities | (36.8)us-gaap_DerivativeLiabilities
Net amounts recognized in Other Assets | 56.4 us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet | 69.2 us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet
Interest Rate Contract | Over the Counter [Member] |  |
Derivative [Line Items] |  |
Derivative Asset | 1.0 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember | 2.4 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember
Derivative Liability | (5.4)us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember | (11.7)us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember
Net amounts recognized in Other Assets | (4.4)us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember | (9.3)us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember
Interest Rate Contract | Exchange Traded [Member] |  |
Derivative [Line Items] |  |
Derivative Asset | 2.8 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember | 1.0 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember
Derivative Liability | (0.1)us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember | (1.6)us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember
Net amounts recognized in Other Assets | 2.7 us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember | (0.6)us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember
Foreign Exchange Contract | Over the Counter [Member] |  |
Derivative [Line Items] |  |
Derivative Asset | 45.5 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember | 67.8 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember
Derivative Liability | 0 us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember | (12.0)us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember
Net amounts recognized in Other Assets | 45.5 us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember | 55.8 us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember
Foreign Exchange Contract | Exchange Traded [Member] |  |
Derivative [Line Items] |  |
Derivative Asset | 0 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember | 2.3 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember
Derivative Liability | (1.4)us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember | 0 us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember
Net amounts recognized in Other Assets | (1.4)us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember | 2.3 us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_ForeignExchangeContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember
Equity Contract | Over the Counter [Member] |  |
Derivative [Line Items] |  |
Derivative Asset | 11.7 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember | 30.7 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember
Derivative Liability | (0.2)us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember | (9.2)us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember
Net amounts recognized in Other Assets | 11.5 us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember | 21.5 us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_OverTheCounterMember
Equity Contract | Exchange Traded [Member] |  |
Derivative [Line Items] |  |
Derivative Asset | 3.4 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember | 1.8 us-gaap_DerivativeAssets / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember
Derivative Liability | (0.9)us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember | (2.3)us-gaap_DerivativeLiabilities / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember
Net amounts recognized in Other Assets | $ 2.5 us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember | $ (0.5)us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_EquityContractMember / dei_LegalEntityAxis = wtm_WhiteMountainsLifeReMember / us-gaap_TransactionTypeAxis = us-gaap_ExchangeTradedMember

X
- Definition Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. + 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 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312 Reference 5: 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 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226008-175313 + Details
Name: | us-gaap_DerivativeAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The net amount as of the balance sheet date of the fair value of derivative assets and derivative liabilities that in accordance with the entity's accounting policy were offset against collateral under a master netting arrangement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41678-113959 + Details
Name: | us-gaap_DerivativeFairValueAmountOffsetAgainstCollateralNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset. + 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 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=20225523&loc=SL20225862-175312 Reference 5: 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 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=28370219&loc=SL20226008-175313 + Details
Name: | us-gaap_DerivativeLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration