Name:	ace_EquitySecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
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Aggregate loss on all equity securities recognized in earnings during the period, before tax effects excluding other than temporary impairments.

No definition available.

Name:	ace_EquitySecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Net realized gains/losses and OCI relating to equity securities as a result of conditions which caused the company to conclude the decline in the fair value of certain investments was other than temporary.

No definition available.

Name:	ace_EquitySecuritiesNetRealizedGainsLossesTotal
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Aggregate gain/loss relating to fair value adjustments on insurance derivative instruments recognized in earnings during the period, before tax effects.

No definition available.

Name:	ace_FairValueAdjustmentsOnInsuranceDerivativeGainsLosses
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Aggregate gain on all equity securities recognized in earnings during the period, before tax effects excluding other than temporary impairments.

No definition available.

Name:	ace_FixedMaturitiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
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Aggregate loss on all fixed maturities securities recognized in earnings during the period, before tax effects excluding other than temporary impairments.

No definition available.

Name:	ace_FixedMaturitiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Net realized gains/losses and OCI relating to fixed maturities as a result of conditions which caused the company to conclude the decline in the fair value of certain investments was other than temporary.

No definition available.

Name:	ace_FixedMaturitiesNetRealizedGainsLossesTotal
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
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The gross decline in fair value that is deemed to be "other than temporary" as it relates to fixed maturities.

No definition available.

Name:	ace_FixedMaturitiesOtherThanTemporaryImpairmentsGross
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

The decline in fair value that is deemed to be "other than temporary" reflected in other comprehensive income (pre-tax) as it relates to fixed maturities.

No definition available.

Name:	ace_FixedMaturitiesOtherThanTemporaryImpairmentsInOtherComprehensiveIncomePreTax
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The net decline in fair value that is deemed to be "other than temporary" as it relates to fixed maturities (net of other than temporary impairments in other comprehensive income).

No definition available.

Name:	ace_FixedMaturitiesOtherThanTemporaryImpairmentsNet
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Aggregate gain/loss on all investment and embedded derivative instruments recognized in earnings during the period, before tax effects.

No definition available.

Name:	ace_InvestmentAndEmbeddedDerivativeInstrumentsGainsLosses
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The net realized gains or losses on investments, derivative instruments, and foreign exchange recognized during the period.

No definition available.

Name:	ace_NetRealizedGainsLosses
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Aggregate gain/loss on all other derivative instruments recognized in earnings during the period, before tax effects

No definition available.

Name:	ace_OtherDerivativeInstrumentsGainsLosses
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The decline in fair value that is deemed to be "other than temporary" as it relates to other investments.

No definition available.

Name:	ace_OtherInvestmentsOtherThanTemporaryImpairments
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Aggregate gain/loss on all other investments recognized in earnings during the period, before tax effects.

No definition available.

Name:	ace_OtherRealizedGainsLosses
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Aggregate gain/loss on all Standard and Poors put options and futures recognized in earnings during the period, before tax effects.

No definition available.

Name:	ace_StandardAndPoorsPutOptionsAndFuturesGainsLosses
Namespace Prefix:	ace_
Data Type:	xbrli:monetaryItemType
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This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 19

-Subparagraph h

-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 Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 35

-Paragraph 32

-URI http://asc.fasb.org/extlink&oid=7658923&loc=d3e32787-111569

Name:	us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

The aggregate foreign currency transaction gain (loss) (both realized and unrealized) included in determining net income for the reporting period. Excludes foreign currency transactions designated as hedges of net investment in a foreign entity and intercompany foreign currency transactions that are of a long-term nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements. For certain enterprises, primarily banks, that are dealers in foreign exchange, foreign currency transaction gains (losses) may be disclosed as dealer gains (losses).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 830

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6450189&loc=d3e30690-110894

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 830

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 830

-SubTopic 20

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6450189&loc=d3e30700-110894

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 52

-Paragraph 30

-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.