XML 117 R66.htm IDEA: XBRL DOCUMENT v2.4.1.9

FAIR VALUE MEASUREMENTS (DETAILS) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	$ 12,129,273us-gaap_AvailableForSaleSecuritiesDebtSecurities	$ 11,986,327us-gaap_AvailableForSaleSecuritiesDebtSecurities
Equity securities	567,707us-gaap_AvailableForSaleSecuritiesEquitySecurities	701,987us-gaap_AvailableForSaleSecuritiesEquitySecurities
Other investments	965,465us-gaap_AlternativeInvestmentsFairValueDisclosure	1,045,810us-gaap_AlternativeInvestmentsFairValueDisclosure
Short-term investments	107,534us-gaap_OtherShortTermInvestments	46,212us-gaap_OtherShortTermInvestments
Derivative assets (see Note 7)	7,264us-gaap_DerivativeAssets	7,808us-gaap_DerivativeAssets
Derivative liabilities (see Note 7)	18,329us-gaap_DerivativeLiabilities	1,967us-gaap_DerivativeLiabilities
Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	12,129,273us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	11,986,327us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Equity securities	567,707us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	701,987us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Other investments	965,465us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	1,045,810us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Short-term investments	107,534us-gaap_OtherShortTermInvestments / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	46,212us-gaap_OtherShortTermInvestments / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Derivative assets (see Note 7)	7,264us-gaap_DerivativeAssets / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	7,808us-gaap_DerivativeAssets / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Total assets	13,777,243us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	13,788,144us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Derivative liabilities (see Note 7)	18,329us-gaap_DerivativeLiabilities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	1,967us-gaap_DerivativeLiabilities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Cash settled awards (see Note 16)	20,518us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	8,693us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Total liabilities	38,847us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	10,660us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
US Government and Agency [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,620,077us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember	1,388,698us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember
US Government and Agency [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,620,077us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember	1,388,698us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember
Non-US Government [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,033,543us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ForeignGovernmentDebtSecuritiesMember	1,176,382us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ForeignGovernmentDebtSecuritiesMember
Non-US Government [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,033,543us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ForeignGovernmentDebtSecuritiesMember	1,176,382us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ForeignGovernmentDebtSecuritiesMember
Corporate Debt [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	4,361,124us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember	3,608,238us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember
Corporate Debt [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	4,361,124us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember	3,608,238us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember
Agency RMBS [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	2,278,108us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember	2,448,827us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Agency RMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	2,278,108us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember	2,448,827us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
CMBS [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,096,888us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommercialMortgageBackedSecuritiesMember	797,414us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommercialMortgageBackedSecuritiesMember
CMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,096,888us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommercialMortgageBackedSecuritiesMember	797,414us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommercialMortgageBackedSecuritiesMember
Non-Agency RMBS [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	73,086us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember	67,567us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
Non-Agency RMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	73,086us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember	67,567us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
ABS [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,461,586us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember	953,451us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember
ABS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,461,586us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember	953,451us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember
Municipals [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	204,861us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember	1,545,750us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember
Municipals [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	204,861us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember	1,545,750us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember
Common Stock [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommonStockMember	438,318us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommonStockMember
Common Stock [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommonStockMember	438,318us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommonStockMember
Exchange-Traded Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	454,890us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ExchangeTradedFundsMember	138,847us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ExchangeTradedFundsMember
Exchange-Traded Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	454,890us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ExchangeTradedFundsMember	138,847us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ExchangeTradedFundsMember
Non-U.S. Bond Mutual Funds [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	112,817us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_NonUnitedStatesBondMutualFundMember	124,822us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_NonUnitedStatesBondMutualFundMember
Non-U.S. Bond Mutual Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	112,817us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_NonUnitedStatesBondMutualFundMember	124,822us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_NonUnitedStatesBondMutualFundMember
Hedge funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	818,539us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_HedgeFundsMember	949,810us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_HedgeFundsMember
Direct Lending Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	54,438us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_DirectLendingFundsMember	22,134us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_DirectLendingFundsMember
CLO-Equities [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	92,488us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_CloEquityTranchedSecuritiesMember	73,866us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_CloEquityTranchedSecuritiesMember
Level 1 [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,497,922us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	1,119,632us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Equity securities	454,890us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	577,165us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Other investments	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Short-term investments	0us-gaap_OtherShortTermInvestments / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	0us-gaap_OtherShortTermInvestments / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Derivative assets (see Note 7)	0us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	0us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Total assets	1,952,812us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	1,696,797us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Derivative liabilities (see Note 7)	0us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	0us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Cash settled awards (see Note 16)	0us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	0us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Total liabilities	0us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	0us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Level 1 [Member] | US Government and Agency [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,497,922us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember	1,119,632us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember
Level 1 [Member] | Non-US Government [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ForeignGovernmentDebtSecuritiesMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ForeignGovernmentDebtSecuritiesMember
Level 1 [Member] | Corporate Debt [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember
Level 1 [Member] | Agency RMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Level 1 [Member] | CMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommercialMortgageBackedSecuritiesMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommercialMortgageBackedSecuritiesMember
Level 1 [Member] | Non-Agency RMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
Level 1 [Member] | ABS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember
Level 1 [Member] | Municipals [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember
Level 1 [Member] | Common Stock [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommonStockMember	438,318us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommonStockMember
Level 1 [Member] | Exchange-Traded Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	454,890us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ExchangeTradedFundsMember	138,847us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ExchangeTradedFundsMember
Level 1 [Member] | Non-U.S. Bond Mutual Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_NonUnitedStatesBondMutualFundMember	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_NonUnitedStatesBondMutualFundMember
Level 1 [Member] | Hedge funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_HedgeFundsMember	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_HedgeFundsMember
Level 1 [Member] | Direct Lending Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_DirectLendingFundsMember	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_DirectLendingFundsMember
Level 1 [Member] | CLO-Equities [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_CloEquityTranchedSecuritiesMember	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel1Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_CloEquityTranchedSecuritiesMember
Level 2 [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	10,557,720us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	10,831,878us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Equity securities	112,817us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	124,822us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Other investments	347,621us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	488,755us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Short-term investments	107,534us-gaap_OtherShortTermInvestments / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	46,212us-gaap_OtherShortTermInvestments / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Derivative assets (see Note 7)	7,153us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	6,824us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Total assets	11,132,845us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	11,498,491us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Derivative liabilities (see Note 7)	3,041us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	1,152us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Cash settled awards (see Note 16)	20,518us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	8,693us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Total liabilities	23,559us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	9,845us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Level 2 [Member] | US Government and Agency [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	122,155us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember	269,066us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember
Level 2 [Member] | Non-US Government [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,033,543us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ForeignGovernmentDebtSecuritiesMember	1,176,382us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ForeignGovernmentDebtSecuritiesMember
Level 2 [Member] | Corporate Debt [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	4,345,287us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember	3,608,238us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember
Level 2 [Member] | Agency RMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	2,278,108us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember	2,448,827us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Level 2 [Member] | CMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,079,125us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommercialMortgageBackedSecuritiesMember	793,396us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommercialMortgageBackedSecuritiesMember
Level 2 [Member] | Non-Agency RMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	73,086us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember	67,567us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
Level 2 [Member] | ABS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	1,421,555us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember	922,652us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember
Level 2 [Member] | Municipals [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	204,861us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember	1,545,750us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember
Level 2 [Member] | Common Stock [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommonStockMember	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommonStockMember
Level 2 [Member] | Exchange-Traded Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ExchangeTradedFundsMember	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ExchangeTradedFundsMember
Level 2 [Member] | Non-U.S. Bond Mutual Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	112,817us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_NonUnitedStatesBondMutualFundMember	124,822us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_NonUnitedStatesBondMutualFundMember
Level 2 [Member] | Hedge funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	347,621us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_HedgeFundsMember	488,755us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_HedgeFundsMember
Level 2 [Member] | Direct Lending Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_DirectLendingFundsMember	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_DirectLendingFundsMember
Level 2 [Member] | CLO-Equities [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_CloEquityTranchedSecuritiesMember	0us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_CloEquityTranchedSecuritiesMember
Level 3 [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	73,631us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	34,817us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Equity securities	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Other investments	617,844us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	557,055us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Short-term investments	0us-gaap_OtherShortTermInvestments / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	0us-gaap_OtherShortTermInvestments / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Derivative assets (see Note 7)	111us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	984us-gaap_DerivativeAssets / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Total assets	691,586us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	592,856us-gaap_AssetsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Derivative liabilities (see Note 7)	15,288us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	815us-gaap_DerivativeLiabilities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Cash settled awards (see Note 16)	0us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	0us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Total liabilities	15,288us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember	815us-gaap_LiabilitiesFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember
Level 3 [Member] | US Government and Agency [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USTreasuryAndGovernmentMember
Level 3 [Member] | Non-US Government [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ForeignGovernmentDebtSecuritiesMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ForeignGovernmentDebtSecuritiesMember
Level 3 [Member] | Corporate Debt [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	15,837us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CorporateDebtSecuritiesMember
Level 3 [Member] | Agency RMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Level 3 [Member] | CMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	17,763us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommercialMortgageBackedSecuritiesMember	4,018us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommercialMortgageBackedSecuritiesMember
Level 3 [Member] | Non-Agency RMBS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
Level 3 [Member] | ABS [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	40,031us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember	30,799us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember
Level 3 [Member] | Municipals [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fixed maturities	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember	0us-gaap_AvailableForSaleSecuritiesDebtSecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_USStatesAndPoliticalSubdivisionsMember
Level 3 [Member] | Common Stock [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommonStockMember	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_CommonStockMember
Level 3 [Member] | Exchange-Traded Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ExchangeTradedFundsMember	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_ExchangeTradedFundsMember
Level 3 [Member] | Non-U.S. Bond Mutual Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Equity securities	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_NonUnitedStatesBondMutualFundMember	0us-gaap_AvailableForSaleSecuritiesEquitySecurities / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_NonUnitedStatesBondMutualFundMember
Level 3 [Member] | Hedge funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	470,918us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_HedgeFundsMember	461,055us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_HedgeFundsMember
Level 3 [Member] | Direct Lending Funds [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	54,438us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_DirectLendingFundsMember	22,134us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_DirectLendingFundsMember
Level 3 [Member] | CLO-Equities [Member] | Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Other investments	$ 92,488us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_CloEquityTranchedSecuritiesMember	$ 73,866us-gaap_AlternativeInvestmentsFairValueDisclosure / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel3Member / us-gaap_FairValueByMeasurementFrequencyAxis = us-gaap_FairValueMeasurementsRecurringMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = axs_CloEquityTranchedSecuritiesMember

X

- Definition

Fair value of investments in certain entities that calculate net asset value per share, including, but not limited to, by unit, membership interest, or other ownership interest. Investments include, but are not limited to, investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 6A

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=SL6742756-110258

+ Details

Name:	us-gaap_AlternativeInvestmentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

+ Details

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of debt securities categorized neither as held-to-maturity nor trading.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (aa)

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 320

-Section 50

-Paragraph 2

-Subparagraph (b)-(g)

-URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62557-112803

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Amount of equity securities categorized neither as held-to-maturity nor as trading.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 320

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62557-112803

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesEquitySecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements.

+ References

No definition available.

+ Details

Name:	us-gaap_DeferredCompensationSharebasedArrangementsLiabilityCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13495-108611



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958



Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226008-175313

+ Details

Name:	us-gaap_DerivativeAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13495-108611



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958



Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226008-175313

+ Details

Name:	us-gaap_DerivativeLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Fair value of financial and nonfinancial obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

+ Details

Name:	us-gaap_LiabilitiesFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Other investments not otherwise specified in the taxonomy that will be realized in a short period of time, usually less than one year or the normal operating cycle, whichever is longer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.8)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.5)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(g))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910



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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 5

-Article 9



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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph g

-Article 7

+ Details

Name:	us-gaap_OtherShortTermInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=axs_CloEquityTranchedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=axs_DirectLendingFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=axs_NonUnitedStatesBondMutualFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_AssetBackedSecuritiesSecuritizedLoansAndReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CommercialMortgageBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_ExchangeTradedFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_ForeignGovernmentDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_HedgeFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USTreasuryAndGovernmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: