INVESTMENTS (DETAILS 5) (USD $) In Millions, unless otherwise specified	Sep. 30, 2011	Dec. 31, 2010
Hedge And Credit Fund Information [Line Items]
Percentage of total hedge fund fair value redeemable in one year or less, including lock-up	95.00%
Percentage of total hedge fund fair value redeemable in three years or less, including lock-up	100.00%
Fair value of hedge fund investments held in side-pockets	$ 3	$ 4
Fair value of credit funds which cannot be liquidated at entity's discretion	$ 31	$ 46
Percentage of total fair value of investments in credit funds that can be liquidated at entity's discretion with annual or semi-annual liquidity	30.00%	32.00%
Percentage of total fair value of investments in credit funds that can be liquidated at entity's discretion with quarterly liquidity with notice requirement	70.00%	68.00%
Minimum [Member]
Hedge And Credit Fund Information [Line Items]
Hedge fund redemption notice required (days)	45
Credit fund redemption notice required (days)	65
Maximum [Member]
Hedge And Credit Fund Information [Line Items]
Hedge fund redemption notice required (days)	95
Credit fund redemption notice required (days)	95

This item represents, as a percentage of total fair value of investments in long/short credit funds that are redeemable by the entity, the amount redeemable with annual or semi-annual liquidity.

Name:	axs_AlternativeInvestmentsLongShortCreditFundsFairValuePercentageOfFairValueThatCanBeLiquidatedAtDiscretionWithAnnualOrSemiannualLiquidity
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Period Type:	instant

- Definition

This item represents, as a percentage of total fair value of investments in long/short credit funds that are redeemable by the entity, the amount redeemable with quarterly liquidity and with a notice requirement.

+ Details

Name:	axs_AlternativeInvestmentsLongShortCreditFundsFairValuePercentageOfFairValueThatCanBeLiquidatedAtDiscretionWithQuarterlyLiquidityNoticeRequirement
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- Definition

This item represents the percentage of total investments in long/short credit funds at fair value which the entity does not have the ability to liquidate at its discretion.

+ Details

Name:	axs_AlternativeInvestmentsLongShortCreditFundsFairValueThatCannotBeLiquidatedAtDiscretion
Namespace Prefix:	axs
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the number of days notice that must be given to the managers of the credit funds in which the entity invests in order to redeem the entity's investments.

+ Details

Name:	axs_AlternativeInvestmentsTotalCreditFundsRedemptionNoticeRequirement
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Period Type:	instant

- Definition

This item represents the fair value of the entity's hedge fund investments, including hedge funds and funds of hedge funds, held in side pockets. Certain hege funds may be allowed to invest a portion of their assets in illiquid securities, such as private equity or convertible debt. In these cases, these illiquid securities are assigned to a designated account (referred to as side pockets) and investors generally lose their redemption rights with respect to these designated accounts. Investors are only able to redeem their interest when the illiquid securities are sold or otherwise deemed liquid by the fund.

+ Details

Name:	axs_AlternativeInvestmentsTotalHedgeFundsFairValueInSidePockets
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Balance Type:	debit
Period Type:	instant

- Definition

This item represents the percentage of total investments in hedge funds at fair value which are redeemable within one year or less, including consideration of lock-up periods which are the initial periods of time when an investor is contractually required to hold the security before having the ability to redeem. Total investments in hedge funds include hedge funds and funds of hedge funds.

+ Details

Name:	axs_AlternativeInvestmentsTotalHedgeFundsPercentageOfTotalFairValueRedeemableInOneYearOrLessIncludingLockUp
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Data Type:	num:percentItemType
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- Definition

This item represents the percentage of total investments in hedge funds at fair value which are redeemable within three years or less, including consideration of lock-up periods which are the initial periods of time when an investor is contractually required to hold the security before having the ability to redeem. Total investments in hedge funds include hedge funds and funds of hedge funds.

+ Details

Name:	axs_AlternativeInvestmentsTotalHedgeFundsPercentageOfTotalFairValueRedeemableInThreeYearsOrLessIncludingLockUp
Namespace Prefix:	axs
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the number of days notice that must be given to the managers of the hedge funds in which the entity invests in order to redeem the entity's investments. This includes the entity's investments in hedge funds and funds of hedge funds.

+ Details

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- Details

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