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outstanding (in shares) Common shares outstanding, beginning of period (in shares) Common shares outstanding, end of period (in shares) Common Stock, Shares, Outstanding Award Timing Disclosures [Line Items] Change in foreign currency translation adjustment Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Corporate debt securities Corporate Debt Securities [Member] Diluted earnings per share available to SiriusPoint common shareholders (in dollars per share) Diluted earnings per share available to SiriusPoint common shareholders (in dollars per share) Earnings Per Share, Diluted Foreign currency translation Liability for Unpaid Claims and Claims Adjustment Expense, Foreign Currency Translation Gain (Loss) Entity Current Reporting Status Entity Current Reporting Status Net cash used in financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation Total Shareholder Return Amount Total Shareholder Return Amount Current expected credit losses (gains) Financing Receivable, Credit Loss, Expense (Reversal) Liabilities, Fair Value Disclosure [Abstract] Liabilities, Fair Value Disclosure [Abstract] Redemption of preference shares Stock Redeemed or Called During Period, Value Intangible asset amortization Amortization of intangible assets Intangible asset amortization Intangible Asset, Finite-Lived, Amortization Expense Line of Credit Facility [Line Items] Line of Credit Facility [Line Items] Ownership [Domain] Ownership [Domain] Net services fee income Net Fee Income Net Fee Income Held for sale asset Increase (Decrease) in Asset, Held-for-Sale Adjustments to reconcile net income to net cash provided by operating activities: Adjustment to Reconcile Net Income to Cash Provided by (Used in) Operating Activity [Abstract] Net written premium Premiums Written, Net Financing activities Cash Provided by (Used in) Financing Activity, Including Discontinued Operation [Abstract] Financial Instruments [Domain] Financial Instruments [Domain] Unearned premiums ceded Increase (Decrease) in Prepaid Reinsurance Premiums Unearned premiums ceded Prepaid Reinsurance Premiums Other long-term investments, Gross unrealized losses Other Long-Term Investments, Accumulated Unrecognized Loss Other Long-Term Investments, Accumulated Unrecognized Loss Derivative assets Derivative assets at fair value Derivative Asset Other revenues Services revenues Other Income Cash, cash equivalents and other Cash, Cash Equivalents And Other [Member] Cash, Cash Equivalents And Other Equity Awards Adjustments, Footnote Equity Awards Adjustments, Footnote [Text Block] Change in cash, cash equivalents and restricted cash classified as assets held for sale Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect, Discontinued Operation Underlying Securities Award Underlying Securities Amount TP Enhanced Fund Third Point Enhanced LP [Member] Third Point Enhanced LP 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Net corporate and other expenses Other Cost and Expense, Operating Related Party Related Party [Member] Insurance Product Line [Domain] Product and Service [Domain] Class of Stock [Line Items] Class of Stock [Line Items] Reinsurance contracts accounted for as derivatives Reinsurance contracts accounted for as derivatives Reinsurance Contract [Member] Reinsurance Contract Entity Interactive Data Current Entity Interactive Data Current Debt securities, trading Debt Securities, Trading [Abstract] Debt Securities, Trading Net (income) loss attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Collateral pledged Derivative Asset, Fair Value of Collateral Deferred tax liability Deferred Income Tax Liabilities, Net Compensation Actually Paid vs. Other Measure Compensation Actually Paid vs. Other Measure [Text Block] Entity Small Business Entity Small Business Comprehensive 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Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Debt Instrument [Axis] Debt Instrument [Axis] Subsequent Event [Table] Subsequent Event [Table] Share compensation Share-Based Payment Arrangement, Noncash Expense Operating lease expense Lease, Cost Due after ten years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost Issuance of common shares upon exercise of warrants (in shares) Stock Issued During Period, Shares, Conversion of Convertible Securities Credit Rating Agencies Credit Rating Agencies [Member] Credit Rating Agencies Investment, Name [Domain] Investment, Name [Domain] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Basic earnings per share available to SiriusPoint common shareholders (in dollars per share) Earnings Per Share, Basic Net proceeds (payments) on deposit liability contracts Proceeds From (Payments For) Deposit Contracts, Liabilities Proceeds From (Payments For) Deposit Contracts, Liabilities Purchases of SiriusPoint common shares under share repurchase program Payments for Repurchase of Common Stock Insider Trading Arrangements [Line Items] Preference shares Nonredeemable Preferred Stock [Member] Schedule of Net Impact on Earnings Relating to Derivatives Derivative Instruments, Gain (Loss) [Table Text Block] Award Type [Axis] Award Type [Axis] Credit Rating [Axis] Credit Rating [Axis] Credit Rating Named Executive Officers, Footnote Named Executive Officers, Footnote [Text Block] Debt securities, available for sale, cost Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss Third Point Venture Offshore Fund I LP Related Party Fund - Third Point Venture Offshore Fund I LP [Member] Related Party Fund - Third Point Venture Offshore 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Additional Paid-in Capital [Member] Entity Filer Category Entity Filer Category Total Debt Securities, Available-for-Sale, Unrealized Loss Position Supplemental Cash Flow Elements [Abstract] Supplemental Cash Flow Elements [Abstract] Director Director [Member] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Due in one year or less Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost Name Trading Arrangement, Individual Name Cash and cash equivalents Cash and Cash Equivalent Proceeds from sales and maturities of debt securities, trading and short-term investments Proceeds From Sales And Maturities Of Debt Securities, Trading And Short-term Investments Proceeds From Sales And Maturities Of Debt Securities, Trading And Short-term Investments Due after ten years Debt Securities, Trading, Maturity, Allocated And Single Maturity Date, Rolling After Ten Years, Fair Value Debt Securities, 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Shares Acquired, Commissions Cost Per Share Net income Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest Award Timing Method Award Timing Method [Text Block] Due after one year through five years Debt Securities, Trading, Maturity, Allocated And Single Maturity Date, Rolling After One Through Five Years, Amortized Cost Debt Securities, Trading, Maturity, Allocated And Single Maturity Date, Rolling After One Through Five Years, Amortized Cost Consolidation Consolidation, Policy [Policy Text Block] Net decrease in cash, cash equivalents and restricted cash Cash, Cash Equivalent, Restricted Cash, and Restricted Cash Equivalent, Period Increase (Decrease), Including Exchange Rate Effect and Discontinued Operation Forgone Recovery, Explanation of Impracticability Forgone Recovery, Explanation of Impracticability [Text Block] Insurance and reinsurance balances receivable, net Premiums Receivable, Net Variable interest entity, primary beneficiary Variable Interest Entity, Primary Beneficiary [Member] Net income available to SiriusPoint Net Income (Loss) Attributable to Parent Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Erroneous Compensation Analysis Erroneous Compensation Analysis [Text Block] Statement [Table] Statement [Table] Segment Measure Reclass Segment Reporting, Reconciling Item, Excluding Corporate Nonsegment [Member] Deferred gain on retroactive reinsurance Increase (Decrease) In Liability For Claims And Claims Adjustment Expense, Deferred Gain On Retroactive Reinsurance Contracts Increase (Decrease) In Liability For Claims And Claims Adjustment Expense, Deferred Gain On Retroactive Reinsurance Contracts Restatement Determination Date: Restatement Determination Date [Axis] Aggregated redemption price Aggregated Redemption Price Aggregated Redemption Price Segment income (loss) Segment Income (Loss) Segment Income (Loss) Net income available to SiriusPoint common shareholders, diluted Net income available to SiriusPoint common shareholders Undistributed Earnings, Diluted Acquisition cost ratio Acquisition Cost Ratio Held for sale liability Increase (Decrease) in Liability, Held-for-Sale Increase (Decrease) in Liability, Held-for-Sale Net realized gains (losses) Debt Securities, Trading, Realized Gain (Loss) International Medical Group, Inc. International Medical Group, Inc. [Member] International Medical Group, Inc. Revenues Revenues [Abstract] Pension Benefits Adjustments, Footnote Pension Benefits Adjustments, Footnote [Text Block] Other long-term investments Other long-term investments Other Long-Term Investments [Member] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract]