XML 34 R21.htm IDEA: XBRL DOCUMENT
v3.20.2

Legal Proceedings | 9 Months Ended
--- | ---
Sep. 30, 2020
Disclosure Legal Proceedings [Abstract] |
Legal Proceedings | Legal ProceedingsThe Company, in common with the insurance industry in general, is subject to litigation and arbitration in the normal course of its business. As of September 30, 2020, the Company was not a party to any litigation or arbitration which is expected by management to have a material adverse effect on the Company’s results of operations and financial condition and liquidity.

X
- Definition Disclosure Legal Proceedings [Abstract] + References No definition available. + Details
Name: | acgl_DisclosureLegalProceedingsAbstract
Namespace Prefix: | acgl_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for legal proceedings, legal contingencies, litigation, regulatory and environmental matters and other contingencies. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -URI http://asc.fasb.org/topic&trid=2127136 + Details
Name: | us-gaap_LegalMattersAndContingenciesTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration