v3.2.0.727

Fair Value Measurements (Narrative) (Detail) | 6 Months Ended
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Jun. 30, 2015
Redemption Notice Periods Lower Range [Member] |
Fair Value Measurements Of Financial Instruments [Line Items] |
Notice period for redemption for alternative investments investment funds, days | 5 days
Redemption Notice Periods Upper Range [Member] |
Fair Value Measurements Of Financial Instruments [Line Items] |
Notice period for redemption for alternative investments investment funds, days | 120 days

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- Definition Fair Value Measurements Of Financial Instruments [Line Items] + References No definition available. + Details
Name: | ace_FairValueMeasurementsOfFinancialInstrumentsLineItems
Namespace Prefix: | ace_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Definition Notice period in days for redemption of investment funds alternative investments (employ various investment strategies such as long/short equity and arbitrage/distressed.) + References No definition available. + Details
Name: | ace_NoticePeriodForRedemptionForAlternativeInvestmentsInvestmentFunds
Namespace Prefix: | ace_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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- Details
Name: | ace_AlternativeInvestmentsLiquidationAxis=ace_RedemptionNoticePeriodLowerRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | ace_AlternativeInvestmentsLiquidationAxis=ace_RedemptionNoticePeriodUpperRangeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |