INVESTMENTS - Equity Securities (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2023	Dec. 31, 2022
Debt and Equity Securities, FV-NI [Line Items]
Cost	$ 564,965	$ 494,356
Gross unrealized gains	103,717	68,694
Gross unrealized losses	(71,990)	(77,797)
Fair value	$ 596,692	485,253
Limited partnership
Debt and Equity Securities, FV-NI [Line Items]
Percentage of investment composition (as a percent)	73.00%
Common stocks
Debt and Equity Securities, FV-NI [Line Items]
Cost	$ 3,130	7,279
Gross unrealized gains	322	636
Gross unrealized losses	(406)	(442)
Fair value	3,046	7,473
Preferred stocks
Debt and Equity Securities, FV-NI [Line Items]
Cost	5,115	115
Gross unrealized gains	0	0
Gross unrealized losses	(131)	(43)
Fair value	4,984	72
Exchange-traded funds
Debt and Equity Securities, FV-NI [Line Items]
Cost	198,244	207,505
Gross unrealized gains	103,126	68,058
Gross unrealized losses	(2,205)	(5,757)
Fair value	299,165	269,806
Bond mutual funds
Debt and Equity Securities, FV-NI [Line Items]
Cost	358,476	279,457
Gross unrealized gains	269	0
Gross unrealized losses	(69,248)	(71,555)
Fair value	$ 289,497	$ 207,902

Percentage Of Investment Composition

No definition available.

Name:	axs_PercentageOfInvestmentComposition
Namespace Prefix:	axs_
Data Type:	dtr-types1:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483467/210-10-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 825
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 1A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482736/825-10-45-1A

+ Details

Name:	us-gaap_EquitySecuritiesFvNi
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Cost of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Excludes equity method investment and investment in equity security without readily determinable fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

+ Details

Name:	us-gaap_EquitySecuritiesFvNiCost
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unrealized gain on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 321
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479536/321-10-50-4

+ Details

Name:	us-gaap_EquitySecuritiesFvNiUnrealizedGain
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of unrealized loss on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

+ Details

Name:	us-gaap_EquitySecuritiesFvNiUnrealizedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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

- Details

Name:	us-gaap_PartnerTypeOfPartnersCapitalAccountAxis=us-gaap_LimitedPartnerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_PreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_ExchangeTradedFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancialInstrumentAxis=axs_NonUnitedStatesBondMutualFundMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: