XML 64 R52.htm IDEA: XBRL DOCUMENT
v3.25.1

Investment Information - Other investments, at fair value (Details) - USD ($) $ in Millions | Mar. 31, 2025 | Dec. 31, 2024
--- | --- | ---
Schedule Of Other Investments [Line Items] |  |
Other investments, at fair value | $ 2,888 | $ 3,066
Other investments |  |
Schedule Of Other Investments [Line Items] |  |
Other investments, at fair value | 1,866 | 2,135
Investment grade fixed income |  |
Schedule Of Other Investments [Line Items] |  |
Other investments, at fair value | 1,085 | 1,055
Private equity |  |
Schedule Of Other Investments [Line Items] |  |
Other investments, at fair value | 252 | 229
Lending |  |
Schedule Of Other Investments [Line Items] |  |
Other investments, at fair value | 237 | 303
Term loan investments |  |
Schedule Of Other Investments [Line Items] |  |
Other investments, at fair value | 200 | 430
Credit related funds |  |
Schedule Of Other Investments [Line Items] |  |
Other investments, at fair value | 74 | 99
Energy |  |
Schedule Of Other Investments [Line Items] |  |
Other investments, at fair value | 18 | 19
Fixed maturities |  |
Schedule Of Other Investments [Line Items] |  |
Other investments, at fair value | 913 | 854
Short term investments |  |
Schedule Of Other Investments [Line Items] |  |
Other investments, at fair value | 104 | 70
Equity securities |  |
Schedule Of Other Investments [Line Items] |  |
Other investments, at fair value | $ 5 | $ 7

X
- Definition -- None. No documentation exists for this element. -- + References No definition available. + Details
Name: | acgl_ScheduleOfOtherInvestmentsLineItems
Namespace Prefix: | acgl_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of investments classified as other. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(12)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: 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)(3)(a)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1 + Details
Name: | us-gaap_OtherInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=acgl_OtherInvestmentsFairValueOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=acgl_InvestmentGradeFixedIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_PrivateEquityFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=acgl_OtherInvestmentsLendingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=acgl_TermLoanInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=acgl_CreditRelatedFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=acgl_OtherInvestmentsEnergyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_FixedIncomeInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=acgl_ShortTermInvestmentsFairValueOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |