XML 63 R49.htm IDEA: XBRL DOCUMENT
v3.21.2

Investment Information - Equity method investments (Details) - USD ($) $ in Thousands | Jun. 30, 2021 | Dec. 31, 2020
--- | --- | ---
Schedule of Equity Method Investments [Line Items] |  |
Investments accounted for using the equity method | $ 2,539,124 | $ 2,047,889
Credit related funds |  |
Schedule of Equity Method Investments [Line Items] |  |
Investments accounted for using the equity method | 883,279 | 740,060
Equity securities |  |
Schedule of Equity Method Investments [Line Items] |  |
Investments accounted for using the equity method | 403,003 | 343,058
Real estate |  |
Schedule of Equity Method Investments [Line Items] |  |
Investments accounted for using the equity method | 323,566 | 258,518
Lending |  |
Schedule of Equity Method Investments [Line Items] |  |
Investments accounted for using the equity method | 295,228 | 179,629
Private equity |  |
Schedule of Equity Method Investments [Line Items] |  |
Investments accounted for using the equity method | 305,662 | 235,289
Infrastructure |  |
Schedule of Equity Method Investments [Line Items] |  |
Investments accounted for using the equity method | 210,174 | 175,882
Energy |  |
Schedule of Equity Method Investments [Line Items] |  |
Investments accounted for using the equity method | $ 118,212 | $ 115,453

X
- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 25 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8813-108599 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_EquityMethodInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

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

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

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_RealEstateFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

X
- Details
Name: | us-gaap_InvestmentTypeAxis=acgl_OtherInvestmentsInfrastructureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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