v2.4.0.6

RELATED PARTY TRANSACTIONS (DETAILS) (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009
Blackstone Debt Advisors [Member] |  |  |
Related Party Transaction [Line Items] |  |  |
Number of CLOs where related party is collateral manager | 4 |  |
Blackstone Alternative Asset Management [Member] |  |  |
Related Party Transaction [Line Items] |  |  |
Number of hedge fund investments where related party is manager | 2 |  |
Number of credit fund investments where related party is manager | 1 |  |
Blackstone Group [Member] |  |  |
Related Party Transaction [Line Items] |  |  |
Management fees paid to related party | $ 2 | $ 2 | $ 1
Percentage of voting rights of related party held in investment portfolio | 1.00% |  |

X
- Definition The number of credit fund investments where fund is managed by a related party. + References No definition available. + Details
Name: | axs_RelatedPartyTransactionNumberOfCreditFundInvestmentsManaged
Namespace Prefix: | axs_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of hedge fund investments where fund is managed by a related party. + References No definition available. + Details
Name: | axs_RelatedPartyTransactionNumberOfHedgeFundInvestmentsManaged
Namespace Prefix: | axs_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Ownership interest in a related party, expressed as a percentage of total voting rights. + References No definition available. + Details
Name: | axs_RelatedPartyTransactionPercentageOfVotingRightsInRelatedParty
Namespace Prefix: | axs_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of collateralized loan obligation investments where collateral manager is a related party. + References No definition available. + Details
Name: | axs_RelatedPartyTransactionsNumberOfCollateralizedLoanObligationInvestmentsCollateralManager
Namespace Prefix: | axs_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expenses recognized during the period resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 57 -Paragraph 2 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 + Details
Name: | us-gaap_RelatedPartyTransactionExpensesFromTransactionsWithRelatedParty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration