DEBT FINANCING ARRANGEMENTS (DETAILS 2) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011
Citibank Letter Of Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum capacity	$ 750
Letters of credit outstanding	397
Termination notice required by lender (days)	30
Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Maximum capacity	500
Potential increase in principal amount	250
Letters of credit outstanding	$ 0
Term of facility (years)	3

Prior notice (in days) required by the lender in order to terminate the line of credit facility.

No definition available.

Name:	axs_LineOfCreditFacilityLenderTerminationNotice
Namespace Prefix:	axs_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

The potential increase in the maximum borrowing capacity under the credit facility at the request of the entity, subject to specified conditions.

+ References

No definition available.

+ Details

Name:	axs_LineOfCreditFacilityMaximumBorrowingCapacityPotentialIncrease
Namespace Prefix:	axs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The term of the line of credit facility (in years), from issuance to the first expiry date.

+ References

No definition available.

+ Details

Name:	axs_LineOfCreditFacilityTerm
Namespace Prefix:	axs_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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

- Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

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

+ Details

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