XML 108 R97.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Discontinued Operations (Details) - USD ($) $ in Millions |  | 3 Months Ended | 9 Months Ended | 60 Months Ended |
--- | --- | --- | --- | --- | ---
Apr. 18, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Sep. 30, 2015 | Sep. 30, 2016 | Sep. 30, 2015 | Sep. 30, 2016 | Dec. 31, 2015
Discontinued Operations [Line Items} |  |  |  |  |  |  |  |
Sales of unconsolidated affiliates and consolidated subsidiaries, net of cash sold |  |  |  |  | $ 2,657.2 | $ 24.0 |  |
Payments to Acquire Other Investments |  |  |  |  | 37.3 | 30.5 |  |
Investments |  | $ 5,213.5 |  |  | 5,213.5 |  | $ 5,213.5 | $ 4,271.1
Net realized and unrealized investment gains (losses) |  | 26.4 |  | $ (43.9) | 84.0 | (33.9) |  |
Net gain on sale of discontinued operations |  |  |  |  | 414.5 | 18.2 |  |
Net (loss) income from discontinued operations, net of tax |  | 14.0 |  | (3.8) | 7.1 | 59.1 |  |
Other liabilities |  | 210.9 |  |  | 210.9 |  | 210.9 | 220.9
Income Tax Expense (Benefit) |  | (6.7) |  | (1.6) | (22.4) | 0.8 |  |
Net Realized and Unrealized Gain (Loss) on Trading Securities |  | 26.4 |  | (43.9) | 84.0 | (33.9) |  |
Sirius Group |  |  |  |  |  |  |  |
Discontinued Operations [Line Items} |  |  |  |  |  |  |  |
Sales of unconsolidated affiliates and consolidated subsidiaries, net of cash sold | $ 2,600.0 |  | $ 2,600.0 |  |  |  |  |
Payments to Acquire Other Investments | $ 161.8 |  | 161.8 |  |  |  |  |
Investments |  |  |  |  |  |  |  | 686.2
Net realized and unrealized investment gains (losses) |  |  |  | 0.8 | 3.7 | 3.5 |  |
Net gain on sale of discontinued operations |  | (4.0) | 366.6 | 0.0 | 362.6 | 0.0 |  |
Accumulated Other Comprehensive Income Loss Net Of Tax Other Period Increase Decrease |  | 0.0 | 113.3 | (18.5) | 32.0 | (62.1) |  |
Tranzact [Member] |  |  |  |  |  |  |  |
Discontinued Operations [Line Items} |  |  |  |  |  |  |  |
Sales of unconsolidated affiliates and consolidated subsidiaries, net of cash sold |  | 221.3 |  |  |  |  |  |
Net gain on sale of discontinued operations |  | 51.9 |  |  |  |  |  |
Discontinued Operation, Tax Effect of Discontinued Operation |  | 30.2 |  |  |  |  |  |
Esurance |  |  |  |  |  |  |  |
Discontinued Operations [Line Items} |  |  |  |  |  |  |  |
Net gain on sale of discontinued operations |  |  |  | 10.3 |  | 18.2 |  |
Symetra | Sirius Group |  |  |  |  |  |  |  |
Discontinued Operations [Line Items} |  |  |  |  |  |  |  |
Investments |  |  |  |  |  |  |  | $ 528.6
Discontinued Operations [Member] |  |  |  |  |  |  |  |
Discontinued Operations [Line Items} |  |  |  |  |  |  |  |
Net realized and unrealized investment gains (losses) |  | 0.0 |  | (0.9) | (1.5) | 31.4 |  |
Net gain on sale of discontinued operations |  | 14.0 |  | (3.8) | 7.1 | 59.1 |  |
Discontinued Operation, Tax Effect of Discontinued Operation |  | 15.9 |  | (2.3) | 16.9 | (22.2) |  |
Discontinued Operations [Member] | Sirius Group |  |  |  |  |  |  |  |
Discontinued Operations [Line Items} |  |  |  |  |  |  |  |
Net realized and unrealized investment gains (losses) |  |  | 0.0 | (0.9) | (1.5) | 31.4 |  |
Net gain on sale of discontinued operations |  |  | 0.0 | 4.0 | (6.4) | 73.7 |  |
Net (loss) income from discontinued operations, net of tax |  |  |  |  | (4.3) |  |  |
Discontinued Operation, Tax Effect of Discontinued Operation |  |  | $ 0.0 | (2.3) | 3.1 | (22.2) |  |
Discontinued Operations [Member] | Tranzact [Member] |  |  |  |  |  |  |  |
Discontinued Operations [Line Items} |  |  |  |  |  |  |  |
Net (loss) income from discontinued operations, net of tax |  | (2.1) |  | (7.7) | (2.6) | (14.2) |  |
Other liabilities |  | 2.8 |  |  | 2.8 |  | 2.8 |
Income Tax Expense (Benefit) |  | (14.0) |  |  | $ (14.0) |  |  |
Tax Effect of Extraordinary Item, Gain (Loss) |  | 30.2 |  |  |  |  |  |
Discontinued Operation, Tax Effect of Discontinued Operation |  | (16.1) |  |  |  |  |  |
Discontinued Operations [Member] | OneBeacon Runoff [Member] |  |  |  |  |  |  |  |
Discontinued Operations [Line Items} |  |  |  |  |  |  |  |
Net gain on sale of discontinued operations |  |  |  |  |  | 0.3 |  |
Discontinued Operations [Member] | Esurance |  |  |  |  |  |  |  |
Discontinued Operations [Line Items} |  |  |  |  |  |  |  |
Net gain on sale of discontinued operations |  | $ 10.3 |  | $ 10.3 |  | $ 17.9 | $ 28.3 |

X
- Definition Amount after tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51717284&loc=d3e1361-107760 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3B -URI http://asc.fasb.org/extlink&oid=51716988&loc=SL51721525-107759 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5C -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=51717284&loc=SL51721675-107760 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=51716988&loc=d3e957-107759 + Details
Name: | us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32672-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3B -URI http://asc.fasb.org/extlink&oid=51716988&loc=SL51721525-107759 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3A -URI http://asc.fasb.org/extlink&oid=51716988&loc=SL51721523-107759 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51717284&loc=d3e1361-107760 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5B -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51717284&loc=SL51721673-107760 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=18498875&loc=d3e38679-109324 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5C -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=51717284&loc=SL51721675-107760 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=51716988&loc=d3e1012-107759 + Details
Name: | us-gaap_DiscontinuedOperationTaxEffectOfDiscontinuedOperation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain (loss) of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain (loss) which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains (losses) realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments (OTTI) of the subject investments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (c)-(e) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27357-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(c),9(a)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27405-111563 + Details
Name: | us-gaap_GainLossOnInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.12) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5C -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=51717284&loc=SL51721675-107760 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.14) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=51716988&loc=d3e1012-107759 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3B -URI http://asc.fasb.org/extlink&oid=51716988&loc=SL51721525-107759 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3A -URI http://asc.fasb.org/extlink&oid=51716988&loc=SL51721523-107759 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=51716988&loc=d3e957-107759 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51717284&loc=d3e1361-107760 Reference 9: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 13 -Article 7 Reference 10: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 15 -Article 5 + Details
Name: | us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Income Tax Expense (or Benefit) -URI http://asc.fasb.org/extlink&oid=6515339 + Details
Name: | us-gaap_IncomeTaxExpenseBenefit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Sum of the carrying amounts as of the balance sheet date of all investments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(h)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_Investments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The sum of the realized and unrealized net gain (loss) on trading securities during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27476-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 + Details
Name: | us-gaap_NetRealizedOrUnrealizedGainLossOnTradingSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The aggregate carrying amount, as of the balance sheet date, of liabilities not separately disclosed in the balance sheet. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.15) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_OtherLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The cash outflow associated with other investments held by the entity for investment purposes not otherwise defined in the taxonomy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireOtherInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow associated with the deconsolidation of a previously consolidated subsidiary or sale of an entity that is related to it but not strictly controlled. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromDivestitureOfInterestInSubsidiariesAndAffiliates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The tax effect of gains and losses from events or transactions meeting the criteria of unusual in nature and infrequent in occurrence, thereby meeting the criteria to be classified as an extraordinary item. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32672-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 20 -Section 45 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=18498875&loc=d3e38679-109324 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 20 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=6904752&loc=d3e14571-107780 + Details
Name: | us-gaap_TaxEffectOfExtraordinaryItem
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Includes changes, net of tax, in the net (gain) loss, prior service cost (credit), and transition assets (obligations), as well as minimum pension liability if still remaining, included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost. Also includes change, net of tax, in accumulated gains and losses from derivative instruments (interest rate swaps) designated and qualifying as the effective portion of cash flow hedges. + References No definition available. + Details
Name: | wtm_AccumulatedOtherComprehensiveIncomeLossNetOfTaxOtherPeriodIncreaseDecrease
Namespace Prefix: | wtm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Reinsurance Items + References No definition available. + Details
Name: | wtm_ReinsuranceItemsLineItems
Namespace Prefix: | wtm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=wtm_SiriusGroupMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=wtm_TranzactMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=wtm_EsuranceMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentAxis=wtm_SymetraMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementOperatingActivitiesSegmentAxis=us-gaap_SegmentDiscontinuedOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=wtm_OnebeaconRunoffMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |