Amount of gain (loss), after tax expense or benefit and not previously recognized, resulting from the sale of a business component.

+ References+ Details

Amount of income (loss) from a disposal group, net of income tax before extraordinary items allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Regulation S-X (SX)

-Number 210

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-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 4: http://www.xbrl.org/2003/role/presentationRef

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

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-Name Accounting Research Bulletin (ARB)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 6: http://www.xbrl.org/2003/role/presentationRef

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 9: http://www.xbrl.org/2003/role/presentationRef

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+ Details

- Definition

Amount of income (loss) from a disposal group, net of income tax, reported as a separate component of income before extraordinary items after deduction or consideration of the amount allocable to noncontrolling interests. Includes, net of tax, income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal.

+ References+ Details

Significant Transactions OneBeacon runoff business (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Significant Transactions
Gain (loss) on sale of discontinued operation, net of tax	$ (91.0)	$ (18.2)	$ (91.0)	$ (18.2)
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(15.8)	(12.0)	(24.5)	(7.8)
OneBeacon Runoff [Member]
Significant Transactions
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(100.5)
Gain (loss) on sale of discontinued operation, net of tax	(91.5)
Loss attributable to change in discount rate [Member]
Significant Transactions
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(9.0)
Loss attributable to prior year reserve devolopment [Member]
Significant Transactions
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ (6.5)