v3.2.0.727

Investments (Net Realized Gains (Losses) And Losses Included In Net Realized Gains (Losses) And Other Comprehensive Income) (Detail) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2015 | Jun. 30, 2014 | Jun. 30, 2015 | Jun. 30, 2014
Investments, Debt and Equity Securities [Abstract] |  |  |  |
OTTI on fixed maturities, gross | $ (13) | $ (9) | $ (26) | $ (15)
OTTI on fixed maturities recognized in OCI (pre-tax) | 6 | 1 | 6 | 2
OTTI on fixed maturities, net | (7) | (8) | (20) | (13)
Fixed maturities, Gross realized gains excluding OTTI | 28 | 54 | 72 | 90
Fixed maturities, Gross realized losses excluding OTTI | (16) | (26) | (51) | (46)
Total fixed maturities | 5 | 20 | 1 | 31
OTTI on equity securities | (1) | (1) | (1) | (7)
Equity securities, Gross realized gains excluding OTTI | 30 | 2 | 33 | 4
Equity securities, Gross realized losses excluding OTTI | 0 | 0 | (2) | (1)
Total equity securities | 29 | 1 | 30 | (4)
OTTI on other investments | 0 | (3) | 0 | (3)
Foreign exchange losses | (40) | (14) | (71) | (23)
Investment and embedded derivative instruments | 27 | (15) | 28 | (40)
Fair value adjustments on insurance derivative | 104 | 2 | 59 | (46)
S&P put options and futures | (2) | (72) | (14) | (91)
Other derivative instruments | (1) | 9 | (1) | 7
Other | 4 | (1) | 5 | (8)
Total net realized gains (losses) (includes $34, $21, $31, and $27 reclassified from AOCI) | $ 126 | $ (73) | $ 37 | $ (177)

X
- Definition Aggregate gains on all equity securities recognized in earnings during the period, before tax effects excluding other than temporary impairments. + References No definition available. + Details
Name: | ace_EquitySecuritiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate loss on all equity securities recognized in earnings during the period, before tax effects excluding other than temporary impairments. + References No definition available. + Details
Name: | ace_EquitySecuritiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition 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. + References No definition available. + Details
Name: | ace_EquitySecuritiesNetRealizedGainsLossesTotal
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate gain/loss relating to fair value adjustments on insurance derivative instruments recognized in earnings during the period, before tax effects. + References No definition available. + Details
Name: | ace_FairValueAdjustmentsOnInsuranceDerivativeGainsLosses
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate gain on all equity securities recognized in earnings during the period, before tax effects excluding other than temporary impairments. + References No definition available. + Details
Name: | ace_FixedMaturitiesGrossRealizedGainsExcludingOtherThanTemporaryImpairments
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate loss on all fixed maturities securities recognized in earnings during the period, before tax effects excluding other than temporary impairments. + References No definition available. + Details
Name: | ace_FixedMaturitiesGrossRealizedLossesExcludingOtherThanTemporaryImpairments
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition 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. + References No definition available. + Details
Name: | ace_FixedMaturitiesNetRealizedGainsLossesTotal
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The gross decline in fair value that is deemed to be "other than temporary" as it relates to fixed maturities. + References No definition available. + Details
Name: | ace_FixedMaturitiesOtherThanTemporaryImpairmentsGross
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition 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. + References No definition available. + Details
Name: | ace_FixedMaturitiesOtherThanTemporaryImpairmentsInOtherComprehensiveIncomePreTax
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition 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). + References No definition available. + Details
Name: | ace_FixedMaturitiesOtherThanTemporaryImpairmentsNet
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate gain/loss on all investment and embedded derivative instruments recognized in earnings during the period, before tax effects. + References No definition available. + Details
Name: | ace_InvestmentAndEmbeddedDerivativeInstrumentsGainsLosses
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The net realized gains or losses on investments, derivative instruments, and foreign exchange recognized during the period. + References No definition available. + Details
Name: | ace_NetRealizedGainsLosses
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate gain/loss on all other derivative instruments recognized in earnings during the period, before tax effects + References No definition available. + Details
Name: | ace_OtherDerivativeInstrumentsGainsLosses
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The decline in fair value that is deemed to be "other than temporary" as it relates to other investments. + References No definition available. + Details
Name: | ace_OtherInvestmentsOtherThanTemporaryImpairments
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate gain/loss on all other investments recognized in earnings during the period, before tax effects. + References No definition available. + Details
Name: | ace_OtherRealizedGainsLosses
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate gain/loss on all Standard and Poors put options and futures recognized in earnings during the period, before tax effects. + References No definition available. + Details
Name: | ace_StandardAndPoorsPutOptionsAndFuturesGainsLosses
Namespace Prefix: | ace_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition 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. + References Reference 1: 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=49116238&loc=d3e32787-111569 + Details
Name: | us-gaap_EquityMethodInvestmentOtherThanTemporaryImpairment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement. + References Reference 1: 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 2: 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 3: 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 + Details
Name: | us-gaap_ForeignCurrencyTransactionGainLossBeforeTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration