XML 84 R67.htm IDEA: XBRL DOCUMENT
v3.20.4

Short Duration Contracts - Claims development - Mortgage (Details) | 12 Months Ended |  |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2020 USD ($) claims | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($) | Dec. 31, 2012 USD ($)
Claims Development [Line Items] |  |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | $ 11,923,393,000 |  |  |  |  |  |  |  |
Mortgage |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 2,179,937,000 |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 1,570,996,000 |  |  |  |  |  |  |  |
All outstanding liabilities before 2012, net of reinsurance | 14,504,000 |  |  |  |  |  |  |  |
Liabilities for losses and loss adjustment expenses, net of reinsurance | 623,445,000 |  |  |  |  |  |  |  |
Large claim size threshold | 250,000 |  |  |  |  |  |  |  |
Mortgage | 2012 |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | 456,331,000 | $ 456,286,000 | $ 458,065,000 | $ 459,467,000 | $ 467,296,000 | $ 469,238,000 | $ 475,317,000 | $ 480,592,000 | $ 520,835,000
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 453,587,000 | 452,348,000 | 448,151,000 | 441,577,000 | 426,024,000 | 395,695,000 | 327,605,000 | 186,605,000 | $ (106,065,000)
Total of IBNR liabilities plus expected development on reported claims | $ 5,000 |  |  |  |  |  |  |  |
Cumulative number of paid claims | claims | 15,083 |  |  |  |  |  |  |  |
Mortgage | 2013 |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 391,062,000 | 390,987,000 | 393,149,000 | 395,693,000 | 405,809,000 | 411,793,000 | 419,668,000 | 469,311,000 |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 387,894,000 | 386,853,000 | 382,200,000 | 373,909,000 | 353,189,000 | 308,956,000 | 203,957,000 | $ 41,447,000 |
Total of IBNR liabilities plus expected development on reported claims | $ 3,000 |  |  |  |  |  |  |  |
Cumulative number of paid claims | claims | 9,471 |  |  |  |  |  |  |  |
Mortgage | 2014 |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 262,682,000 | 261,091,000 | 265,992,000 | 266,027,000 | 279,434,000 | 297,151,000 | 316,095,000 |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 256,285,000 | 254,175,000 | 247,038,000 | 233,879,000 | 201,925,000 | 129,159,000 | $ 20,099,000 |  |
Total of IBNR liabilities plus expected development on reported claims | $ 7,000 |  |  |  |  |  |  |  |
Cumulative number of paid claims | claims | 6,290 |  |  |  |  |  |  |  |
Mortgage | 2015 |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 190,913,000 | 189,235,000 | 194,677,000 | 198,001,000 | 197,238,000 | 222,790,000 |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 183,472,000 | 180,321,000 | 171,337,000 | 151,222,000 | 92,431,000 | $ 16,159,000 |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 4,000 |  |  |  |  |  |  |  |
Cumulative number of paid claims | claims | 4,543 |  |  |  |  |  |  |  |
Mortgage | 2016 |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 142,392,000 | 140,608,000 | 148,715,000 | 170,532,000 | 183,556,000 |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 131,161,000 | 127,286,000 | 113,357,000 | 72,201,000 | $ 11,462,000 |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 7,000 |  |  |  |  |  |  |  |
Cumulative number of paid claims | claims | 3,411 |  |  |  |  |  |  |  |
Mortgage | 2017 |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 108,181,000 | 107,255,000 | 132,220,000 | 179,376,000 |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 87,317,000 | 78,650,000 | 48,112,000 | $ 8,622,000 |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 630,000 |  |  |  |  |  |  |  |
Cumulative number of paid claims | claims | 2,429 |  |  |  |  |  |  |  |
Mortgage | 2018 |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 89,120,000 | 96,357,000 | 132,318,000 |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 50,135,000 | 31,478,000 | $ 3,966,000 |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 1,281,000 |  |  |  |  |  |  |  |
Cumulative number of paid claims | claims | 1,512 |  |  |  |  |  |  |  |
Mortgage | 2019 |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 119,253,000 | 108,424,000 |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 20,105,000 | $ 2,899,000 |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 2,921,000 |  |  |  |  |  |  |  |
Cumulative number of paid claims | claims | 566 |  |  |  |  |  |  |  |
Mortgage | 2020 |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |
Incurred losses and allocated loss adjustment expenses, net of reinsurance | $ 420,003,000 |  |  |  |  |  |  |  |
Cumulative paid losses and allocated loss adjustment expenses, net of reinsurance | 1,040,000 |  |  |  |  |  |  |  |
Total of IBNR liabilities plus expected development on reported claims | $ 15,879,000 |  |  |  |  |  |  |  |
Cumulative number of paid claims | claims | 32 |  |  |  |  |  |  |  |

X
- Definition Short Duration Contracts, Large Claim Size Threshold + References No definition available. + Details
Name: | acgl_ShortDurationContractsLargeClaimSizeThreshold
Namespace Prefix: | acgl_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Short-duration Insurance Contracts, Number of Paid Claims + References No definition available. + Details
Name: | acgl_ShortdurationInsuranceContractsNumberofPaidClaims
Namespace Prefix: | acgl_
Data Type: | xbrli:integerItemType
Balance Type: | na
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_ClaimsDevelopmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, after reinsurance, of paid claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4B -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=116884468&loc=SL65671311-158438 + Details
Name: | us-gaap_ShortdurationInsuranceContractsCumulativePaidClaimsAndAllocatedClaimAdjustmentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Undiscounted amount, after reinsurance, of incurred-but-not-reported (IBNR) liabilities plus expected development on reported claims, for claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4E -URI http://asc.fasb.org/extlink&oid=116884468&loc=SL65671321-158438 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4D -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=116884468&loc=SL65671317-158438 + Details
Name: | us-gaap_ShortdurationInsuranceContractsIncurredButNotReportedIbnrClaimsLiabilityNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Undiscounted amount, after reinsurance, of incurred claims and allocated claim adjustment expense used in claims development for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4B -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=116884468&loc=SL65671311-158438 + Details
Name: | us-gaap_ShortdurationInsuranceContractsIncurredClaimsAndAllocatedClaimAdjustmentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Undiscounted amount, after reinsurance, of the liability for unpaid claims and allocated claim adjustment expense for short-duration insurance contracts. Excludes unallocated claim adjustment expense. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4C -URI http://asc.fasb.org/extlink&oid=116884468&loc=SL65671315-158438 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4B -URI http://asc.fasb.org/extlink&oid=116884468&loc=SL65671311-158438 + Details
Name: | us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Undiscounted amount, after reinsurance, of the liability for unpaid claims and allocated claim adjustment expense for short-duration insurance contracts for accident years not separately presented in claim development information. Excludes unallocated claim adjustment expense. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 4B -URI http://asc.fasb.org/extlink&oid=116884468&loc=SL65671311-158438 + Details
Name: | us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndAllocatedClaimAdjustmentExpenseNetNotSeparatelyPresented
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_StatementBusinessSegmentsAxis=acgl_MortgageSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortdurationInsuranceContractsAccidentYear2012Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortdurationInsuranceContractsAccidentYear2013Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortdurationInsuranceContractsAccidentYear2014Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortdurationInsuranceContractsAccidentYear2015Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractsAccidentYear2017Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractsAccidentYear2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortdurationInsuranceContractsAccidentYearAxis=us-gaap_ShortDurationInsuranceContractAccidentYear2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |