| Current Federal Tax Expense (Benefit) | 253.00M | 2025-01-01 → 2025-12-31 |
| SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Deferred Policy Acquisition Cost | 2.11B | as of 2025-12-31 |
| Current State and Local Tax Expense (Benefit) | 17.00M | 2025-01-01 → 2025-12-31 |
| SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense | 72.05B | as of 2025-12-31 |
| SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Unearned Premium | 17.99B | as of 2025-12-31 |
| Current Foreign Tax Expense (Benefit) | 635.00M | 2025-01-01 → 2025-12-31 |
| SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Policy Claim and Benefit Payable | 0 | as of 2025-12-31 |
| SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Revenue | 23.75B | 2025-01-01 → 2025-12-31 |
| SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Net Investment Income | 4.21B | 2025-01-01 → 2025-12-31 |
| SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Benefit, Claim, Loss and Settlement Expenses | 14.16B | 2025-01-01 → 2025-12-31 |
| Deferred Federal Income Tax Expense (Benefit) | -221.00M | 2025-01-01 → 2025-12-31 |
| SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Amortization of Deferred Policy Acquisition Cost | 3.37B | 2025-01-01 → 2025-12-31 |
| Deferred State and Local Income Tax Expense (Benefit) | -12.00M | 2025-01-01 → 2025-12-31 |
| SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense | 5.05B | 2025-01-01 → 2025-12-31 |
| SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Premium Written | 23.67B | 2025-01-01 → 2025-12-31 |
| Deferred Foreign Income Tax Expense (Benefit) | 110.00M | 2025-01-01 → 2025-12-31 |
| Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense | 13.00M | 2025-01-01 → 2025-12-31 |
| Alternative Investment | 3.46B | as of 2025-12-31 |
| Derivatives used in Net Investment Hedge, Increase (Decrease), Gross of Tax | -116.00M | 2025-01-01 → 2025-12-31 |
| Share-based Payment Arrangement, Expense | 207.00M | 2025-01-01 → 2025-12-31 |
| SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Cost | 93.88B | as of 2025-12-31 |
| SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Fair Value | 92.95B | as of 2025-12-31 |
| Securities for Reverse Repurchase Agreements | 3.60B | as of 2025-12-31 |
| SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount | 93.00B | as of 2025-12-31 |
| Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount | 815.00M | 2025-01-01 → 2025-12-31 |
| Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount | 14.00M | 2025-01-01 → 2025-12-31 |
| Share-based Payment Arrangement, Expense, after Tax | 164.00M | 2025-01-01 → 2025-12-31 |
| EffectiveIncomeTaxRateReconciliationFdiiAmount | 59.00M | 2025-01-01 → 2025-12-31 |
| EffectiveIncomeTaxRateReconciliationCrossBorderOtherAmount | 28.00M | 2025-01-01 → 2025-12-31 |
| Share-based Payment Arrangement, Cash Used to Settle Award | 34.00M | 2025-01-01 → 2025-12-31 |
| Share-based Payment Arrangement, Nonvested Award, Excluding Option, Cost Not yet Recognized, Amount | 27.00M | as of 2025-12-31 |
| Direct Premiums Earned | 31.46B | 2025-01-01 → 2025-12-31 |
| Ceded Premiums Earned | 11.46B | 2025-01-01 → 2025-12-31 |
| Effective Income Tax Rate Reconciliation, Tax Credit, Amount | 20.00M | 2025-01-01 → 2025-12-31 |
| Assumed Premiums Earned | 3.75B | 2025-01-01 → 2025-12-31 |
| Equity Securities, FV-NI, Unrealized Gain (Loss) | 654.00M | 2025-01-01 → 2025-12-31 |
| Effective Income Tax Rate Reconciliation, Nondeductible Expense, Other, Amount | 20.00M | 2025-01-01 → 2025-12-31 |
| Equity Securities, FV-NI, Gain (Loss) | 480.00M | 2025-01-01 → 2025-12-31 |
| Effective Income Tax Rate Reconciliation, Tax Contingency, Amount | 17.00M | 2025-01-01 → 2025-12-31 |
| Dividends, Common Stock | 976.00M | 2025-01-01 → 2025-12-31 |
| Debt Securities, Available-for-sale, Realized Gain | 72.00M | 2025-01-01 → 2025-12-31 |
| Debt Securities, Available-for-sale, Realized Loss | 665.00M | 2025-01-01 → 2025-12-31 |
| Debt Securities, Available-for-sale, Realized Gain (Loss) | -593.00M | 2025-01-01 → 2025-12-31 |
| Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount | -300.00M | 2025-01-01 → 2025-12-31 |
| Derivative Asset, Fair Value, Gross Liability | 164.00M | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost | 21.11B | as of 2025-12-31 |
| Treasury Stock, Value, Acquired, Cost Method | 5.88B | 2025-01-01 → 2025-12-31 |
| Derivative Liability, Fair Value, Gross Asset | 164.00M | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost | 4.86B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost | 23.14B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Amortized Cost | 16.52B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost | 6.10B | as of 2025-12-31 |
| Derivative Liability, Notional Amount | 5.07B | as of 2025-12-31 |
| Derivative Asset, Notional Amount | 2.34B | as of 2025-12-31 |
| Net Income (Loss) from Continuing Operations Available to Common Shareholders, Basic | 3.10B | 2025-01-01 → 2025-12-31 |
| Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value | 21.21B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value | 4.84B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value | 23.21B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after Five Through Ten Years, Fair Value | 16.43B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value | 5.34B | as of 2025-12-31 |
| Reinsurance Recoverable for Unpaid Claims and Claims Adjustments | 28.87B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 193.00M | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 1.68B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | 1.87B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Sold at Par Value | 12.40B | 2025-01-01 → 2025-12-31 |
| Other Intangible Assets, Net | 684.00M | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax | 1.18B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax | 1.88B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 10.19B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 12.87B | as of 2025-12-31 |
| Debt Securities, Available-for-sale, Unrealized Loss Position | 23.05B | as of 2025-12-31 |
| Deferred Tax Assets, Operating Loss Carryforwards | 3.28B | as of 2025-12-31 |
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value | 204.00M | as of 2025-12-31 |
| Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value | 180.00M | as of 2025-12-31 |
| Funds Held under Reinsurance Agreements, Liability | 3.04B | as of 2025-12-31 |
| Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Benefits | 163.00M | as of 2025-12-31 |
| Goodwill, Gross | 6.84B | as of 2025-12-31 |
| Goodwill, Impaired, Accumulated Impairment Loss | 3.41B | as of 2025-12-31 |
| Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Unearned Premiums Reserve | 0 | as of 2025-12-31 |
| Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Loss Reserves | 440.00M | as of 2025-12-31 |
| Deferred Tax Assets, Unrealized Losses on Trading Securities | 336.00M | as of 2025-12-31 |
| Deferred Tax Assets, Unrealized Losses on Available-for-Sale Securities, Gross | 153.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, Year One | 129.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, Year Two | 111.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, Year Three | 97.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, Year Four | 95.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, Year Five | 86.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid, after Year Five | 526.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, to be Paid | 1.04B | as of 2025-12-31 |
| Deferred Tax Assets, Investment in Subsidiaries | 29.00M | as of 2025-12-31 |
| Deferred Tax Assets, Other | 10.00M | as of 2025-12-31 |
| Derivative Liability, Collateral, Right to Reclaim Cash, Offset | 212.00M | as of 2025-12-31 |
| Deferred Tax Assets, Gross | 5.88B | as of 2025-12-31 |
| Deferred Tax Assets, Valuation Allowance | 1.05B | as of 2025-12-31 |
| Derivative Asset, Collateral, Obligation to Return Cash, Offset | 169.00M | as of 2025-12-31 |
| Lessee, Operating Lease, Liability, Undiscounted Excess Amount | 188.00M | as of 2025-12-31 |
| Deferred Tax Assets, Net | 4.48B | as of 2025-12-31 |
| Deferred Policy Acquisition Cost, Capitalization | 3.38B | 2025-01-01 → 2025-12-31 |
| Deferred Policy Acquisition Costs, Disposition | 0 | 2025-01-01 → 2025-12-31 |
| Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount | 13.00M | 2025-01-01 → 2025-12-31 |
| Operating Lease, Lease Income, Lease Payments | 156.00M | 2025-01-01 → 2025-12-31 |
| Deferred Tax Liabilities, Net | 343.00M | as of 2025-12-31 |
| Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Amortization | 3.37B | 2025-01-01 → 2025-12-31 |
| Reinsurance Recoverable, Credit Loss Expense (Reversal) | 28.00M | 2025-01-01 → 2025-12-31 |
| Reinsurance, Loss on Uncollectible Accounts in Period, Amount | 4.00M | 2025-01-01 → 2025-12-31 |
| Other Commitment | 1.50B | as of 2025-12-31 |
| Liability for Unpaid Claims and Claims Adjustment Expense, Foreign Currency Translation Gain (Loss) | 1.23B | 2025-01-01 → 2025-12-31 |
| Current Year Claims and Claims Adjustment Expense | 14.44B | 2025-01-01 → 2025-12-31 |
| Prior Year Claims and Claims Adjustment Expense | -427.00M | 2025-01-01 → 2025-12-31 |
| Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims | 14.16B | 2025-01-01 → 2025-12-31 |
| Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year | 3.90B | 2025-01-01 → 2025-12-31 |
| Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years | 9.97B | 2025-01-01 → 2025-12-31 |
| Operating Loss Carryforwards | 15.61B | as of 2025-12-31 |
| DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossNotPreviouslyRecorded | 28.00M | 2025-01-01 → 2025-12-31 |
| DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossSecuritiesSold | 12.00M | 2025-01-01 → 2025-12-31 |
| DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal | 4.00M | 2025-01-01 → 2025-12-31 |
| DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossWriteoff | 20.00M | 2025-01-01 → 2025-12-31 |
| Tax Credit Carryforward, Valuation Allowance | 300.00M | as of 2025-12-31 |
| Unrecognized Tax Benefits | 1.41B | as of 2025-12-31 |
| Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions | 41.00M | 2025-01-01 → 2025-12-31 |
| Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions | 12.00M | 2025-01-01 → 2025-12-31 |
| Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions | 0 | 2025-01-01 → 2025-12-31 |
| Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations | 1.00M | 2025-01-01 → 2025-12-31 |
| Unrecognized Tax Benefits that Would Impact Effective Tax Rate | 1.40B | as of 2025-12-31 |
| Liability for Future Policy Benefit, before Reinsurance | 1.39B | as of 2025-12-31 |
| Income (Loss) from Continuing Operations before Income Taxes, Domestic | 1.50B | 2025-01-01 → 2025-12-31 |
| Income (Loss) from Continuing Operations before Income Taxes, Foreign | 2.38B | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value | 3.90B | as of 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings | 18.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) | 27.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases | 1.60B | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales | 184.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances | 0 | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements | 654.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, (Sales), Issuances, (Settlements) | 759.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 | 184.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 | 568.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) | 11.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings | -139.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss) | 0 | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases | 0 | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales | 0 | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances | 0 | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements | -130.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases, (Sales), Issuances, (Settlements) | 130.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3 | 0 | 2025-01-01 → 2025-12-31 |
| Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3 | 0 | 2025-01-01 → 2025-12-31 |
| Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss) | -93.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI | 44.00M | 2025-01-01 → 2025-12-31 |
| Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), OCI | 0 | 2025-01-01 → 2025-12-31 |
| Deposit Contracts, Assets | 2.44B | as of 2025-12-31 |
| Collateral Already Posted, Aggregate Fair Value | 362.00M | as of 2025-12-31 |
| Additional Collateral, Aggregate Fair Value | 222.00M | as of 2025-12-31 |
| Embedded Derivative, Fair Value of Embedded Derivative Asset | 3.00B | as of 2025-12-31 |
| Embedded Derivative, Fair Value of Embedded Derivative Liability | 0 | as of 2025-12-31 |
| Deferred Tax Liabilities, Deferred Expense, Deferred Policy Acquisition Cost | 139.00M | as of 2025-12-31 |
| Derivative Liability, Fair Value, Gross Liability | 465.00M | as of 2025-12-31 |
| Derivative Asset, Fair Value, Gross Asset | 338.00M | as of 2025-12-31 |
| Statutory Accounting Practices, Statutory Capital and Surplus Required | 10.35B | as of 2025-12-31 |
| Statutory Accounting Practices, Statutory Net Income Amount | 4.41B | 2025-01-01 → 2025-12-31 |
| Statutory Accounting Practices, Statutory Capital and Surplus, Balance | 28.66B | as of 2025-12-31 |
| Statutory Accounting Practices, Statutory Amount Available for Dividend Payments with Regulatory Approval | 2.60B | as of 2025-12-31 |
| Assets Held by Insurance Regulators | 7.70B | as of 2025-12-31 |