COMMITMENTS AND CONTINGENCIES - Cash and investments (Details)	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Fixed maturity portfolio - corporate issuer concentration limit above A-	2.00%
Fixed maturity portfolio - corporate issuer concentration limit below A-	1.00%

Reflects the maximum amount, expressed as a percentage of fixed maturity value, of concentration of credit risk to any single corporate debt issuer rated A- or above (excluding U.S. government and agency securities).

No definition available.

Name:	axs_Concentrationriskcreditriskfixedmaturitiesmaximumexposurecorporateissueraminusorabovepercentageoffixedmaturityportfolio
Namespace Prefix:	axs_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant