v2.4.0.6

FAIR VALUE MEASUREMENTS (DETAILS) (Income Approach [Member], Level 3 [Member], CLO Equity Tranched Securities [Member]) | 12 Months Ended
--- | ---
Dec. 31, 2011 | Dec. 31, 2010
CLO - equity tranched securities significant valuation inputs [Line Items] |  |
Loss severity rate | 53.50% | 65.00%
Minimum [Member] |  |
CLO - equity tranched securities significant valuation inputs [Line Items] |  |
Default rates | 4.00% | 3.80%
Collateral spreads | 2.60% | 2.40%
Estimated maturity dates (years) | 2.5 | 1.5
Maximum [Member] |  |
CLO - equity tranched securities significant valuation inputs [Line Items] |  |
Default rates | 5.00% | 5.00%
Collateral spreads | 4.20% | 4.20%
Estimated maturity dates (years) | 5.2 | 10.5

X
- Details
Name: | axs_FairValueInputsAssetsQuantitativeInformationLineItems
Namespace Prefix: | axs_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The difference between the interest yield earned on the underlying collateral assets and the interest rates incurred on the debt tranches of the CLO structure. + References No definition available. + Details
Name: | axs_FairValueInputsCollateralSpread
Namespace Prefix: | axs_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The estimated remaining time to maturity of the CLO structure (expressed as a number of years). + References No definition available. + Details
Name: | axs_FairValueInputsEstimatedMaturityDate
Namespace Prefix: | axs_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | duration

X
- Definition Loss, including interest and principal, incurred on a defaulted security, stated as a percentage of the original principal balance, used as an input to measure fair value. + References No definition available. + Details
Name: | axs_FairValueInputsLossSeverity
Namespace Prefix: | axs_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of likelihood a loan will not be repaid and instead default, used as an input to measure fair value. + References No definition available. + Details
Name: | axs_FairValueInputsProbabilityOfDefault
Namespace Prefix: | axs_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration