Statutory Information - Narrative (Details) $ in Millions	12 Months Ended
Dec. 31, 2023 USD ($) subsidiary
Ireland
Statutory Accounting Practices [Line Items]
Number Of Subsidiaries \| subsidiary	3
Mortgage \| North Carolina or Wisconsin
Statutory Accounting Practices [Line Items]
Required contingency loss reserve as a percentage of net earned premiums	50.00%
Withdrawal restriction period	10 years
Withdrawal restriction period, with prior approval	35.00%
Maximum risk to capital ratio	2500.00%
United Guaranty Residential Insurance Company \| North Carolina
Statutory Accounting Practices [Line Items]
Dividends available for payment in 2022, total	$ 180
Arch Re US \| United States
Statutory Accounting Practices [Line Items]
Dividends available for payment in 2022, total	$ 329
Arch Re Bermuda \| Bermuda
Statutory Accounting Practices [Line Items]
Dividends, percentage permitted	25.00%
Dividend required notice period	7 days
Dividends available for payment in 2022 without prior regulatory approval	$ 4,800
Arch Group Reinsurance Ltd \| Bermuda
Statutory Accounting Practices [Line Items]
Dividends, percentage permitted	25.00%
Dividend required notice period	7 days
Arch Mortgage Insurance Company \| WISCONSIN
Statutory Accounting Practices [Line Items]
Dividends available for payment in 2022, total	$ 180
Arch Mortgage Guaranty Company \| WISCONSIN
Statutory Accounting Practices [Line Items]
Dividends available for payment in 2022, total	$ 180

Maximum Risk To Capital Ratio

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- Definition

Number Of Subsidiaries

+ References

No definition available.

+ Details

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- Definition

Statutory Accounting Contingency Loss Reserve Percentage Of Net Earned Premiums

+ References

No definition available.

+ Details

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- Definition

Statutory Accounting Contingency Loss Reserve Percentage Of Net Earned Premiums With Prior Approval

+ References

No definition available.

+ Details

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- Definition

The percentage of total statutory capital and surplus (as shown on its previous financial year's statutory balance sheet) which may be paid out as dividends without the requirement to file an affadavit with the regulatory body stating that the Company will continue to meet required margins.

+ References

No definition available.

+ Details

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- Definition

Statutory Capital And Surplus Notice Period Required For Dividends

+ References

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- Definition

Withdrawal Restriction Period

+ References

No definition available.

+ Details

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- 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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(23)(c))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

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- Definition

Amount of dividends available for payment after computation of statutory restrictions on capital surplus.

+ References

No definition available.

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- Definition

Amount of dividends that can be declared or paid without approval of regulatory agency.

+ References

No definition available.

+ Details

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