XML 102 R140.htm IDEA: XBRL DOCUMENT v2.4.0.6

Commitments and Contingencies (Legal Contingencies) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			1 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jun. 30, 2007 Tribune Company Litigation
Legal Contingency [Abstract]
Sales of unconsolidated affiliates, net of cash sold and held in escrow	$ 24.8	$ 1,010.6	$ 188.3
Net gain on sale of discontinued operation - Esurance		700.0
Disposal group including discontinued operation book value		308.0
Total amount in dispute with Allstate	20.0
DAC amount in dispute with Allstate, pre-tax	24.7
DAC amount in dispute with Allstate, after-tax	16.0
Extra contractual obligation in dispute with Allstate, pre-tax	5.2
Extra contractual obligation in dispute with Allstate, after-tax	3.4
Proceeds in connection with Tribune leveraged buyout				$ 39

X

- Details

Name:	us-gaap_LossContingencyAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
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 Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 15

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 16

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.



Reference 3: 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 4: 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=6943989&loc=d3e3179-108585



Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 51

-Paragraph 39

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_ProceedsFromDivestitureOfInterestInSubsidiariesAndAffiliates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

DAC amount in dispute with Allstate, after-tax.

+ References

No definition available.

+ Details

Name:	wtm_DacAmountInDisputeWithAllstateAfterTax
Namespace Prefix:	wtm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

DAC amount in dispute with Allstate, pre-tax.

+ References

No definition available.

+ Details

Name:	wtm_DacAmountInDisputeWithAllstatePreTax
Namespace Prefix:	wtm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Represents the after-tax gain for the sale of a business.

+ References

No definition available.

+ Details

Name:	wtm_DiscontinuedOperationGainOnDisposalOfDiscontinuedOperationNetOfTax
Namespace Prefix:	wtm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

For the disposal group, including a component of the entity (discontinued operation), it represents the tangible book value of the businesses sold by the entity.

+ References

No definition available.

+ Details

Name:	wtm_DisposalGroupIncludingDiscontinuedOperationBookValue
Namespace Prefix:	wtm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Extra contractual obligation in dispute with Allstate, after-tax.

+ References

No definition available.

+ Details

Name:	wtm_ExtraContractualObligationInDisputeWithAllstateAfterTax
Namespace Prefix:	wtm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Extra contractual obligation in dispute with Allstate, pretax.

+ References

No definition available.

+ Details

Name:	wtm_ExtraContractualObligationInDisputeWithAllstatePreTax
Namespace Prefix:	wtm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Proceeds from Tribune common stock tendered in connecttion with Tribune's leveraged buyout.

+ References

No definition available.

+ Details

Name:	wtm_ProceedsFromTribuneCommonStock
Namespace Prefix:	wtm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Total amount in dispute with Allstate.

+ References

No definition available.

+ Details

Name:	wtm_TotalAmountInDisputeWithAllstate
Namespace Prefix:	wtm_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant