XML 125 R101.htm IDEA: XBRL DOCUMENT
v3.10.0.1

COMMITMENTS AND CONTINGENCIES - Reinsurance and premiums (Details) | 12 Months Ended
--- | ---
Dec. 31, 2018 USD ($) broker | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($)
Concentration Risk [Line Items] |  |  |
Premiums receivable allowance for doubtful accounts | $ 4,000,000 | $ 6,000,000 |
Premiums receivable, bad debt expense charges | $ 0 | $ 0 | $ 1,000,000
Reinsurance Recoverable On Unpaid And Paid Losses | Reinsurer Concentration | Reinsurer 1 |  |  |
Concentration Risk [Line Items] |  |  |
Concentration risk, percentage of total | 13.00% | 12.00% |
Reinsurance Recoverable On Unpaid And Paid Losses | Reinsurer Concentration | Reinsurer 2 |  |  |
Concentration Risk [Line Items] |  |  |
Concentration risk, percentage of total | 10.00% | 11.00% |
Reinsurance Recoverable On Unpaid And Paid Losses | Reinsurer Concentration | Reinsurer 3 |  |  |
Concentration Risk [Line Items] |  |  |
Concentration risk, percentage of total | 10.00% | 7.00% |
Reinsurance Recoverable On Unpaid And Paid Losses | Reinsurer Concentration | Top Ten Reinsurers | AM Best, A- Rating |  |  |
Concentration Risk [Line Items] |  |  |
Concentration risk, percentage of total | 89.50% | 88.80% |
Gross Premiums Written | Customer Concentration |  |  |
Concentration Risk [Line Items] |  |  |
Concentration risk, percentage of total | 43.00% | 49.00% | 52.00%
Concentration risk, number of brokers exceeding threshold | broker | 3 |  |
Gross Premiums Written | Customer Concentration | Marsh & McLennan Companies Inc. |  |  |
Concentration Risk [Line Items] |  |  |
Concentration risk, percentage of total | 17.00% | 20.00% | 21.00%
Gross Premiums Written | Customer Concentration | Aon plc |  |  |
Concentration Risk [Line Items] |  |  |
Concentration risk, percentage of total | 17.00% | 17.00% | 19.00%
Gross Premiums Written | Customer Concentration | Willis Towers Watson PLC |  |  |
Concentration Risk [Line Items] |  |  |
Concentration risk, percentage of total | 9.00% | 12.00% | 12.00%

X
- Definition Number of customers where transactions amount to 10 percent or more of the entity's revenues. + References No definition available. + Details
Name: | axs_SegmentReportingDisclosureOfMajorCustomersNumberOfMajorCustomers
Namespace Prefix: | axs_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ConcentrationRiskLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13531-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109250915&loc=d3e13537-108611 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592 + Details
Name: | us-gaap_ConcentrationRiskPercentage1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The carrying value as of the balance sheet date of the estimated valuation allowance to reduce gross premiums receivable to net realizable value. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(5)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524 + Details
Name: | us-gaap_PremiumsReceivableAllowanceForDoubtfulAccounts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount of decrease during the period to the valuation allowance account representing portions of such account associated with premium receivables that have been determined to be absolutely uncollectible or that were sold or transferred, and which receivables were simultaneously written off. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
Name: | us-gaap_PremiumsReceivableAllowanceForDoubtfulAccountsWriteOffsAgainstAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_ReinsuranceRecoverableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_ReinsurerConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CededCreditRiskAxis=axs_ReinsurerOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CededCreditRiskAxis=axs_ReinsurerTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CededCreditRiskAxis=axs_ReinsurerThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CededCreditRiskAxis=axs_TenLargestReinsurersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingAMBestAxis=srt_AMBestAMinusRatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByBenchmarkAxis=axs_PremiumsWrittenGrossMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CustomerConcentrationRiskMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=axs_MarshMcLennanCompaniesIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=axs_AonplcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MajorCustomersAxis=axs_WillisTowerWatsonPLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |