Business Acquisition [Axis] Business Acquisition [Axis] Reinsurance recoverables, net Increase (Decrease) in Reinsurance Recoverable Potential recoveries Potential Recoveries under Credit Risk Derivatives Represents the potential amount of recoveries under sale of credit protection. Number of putative class actions Loss Contingency, Pending Claims, Number Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Inputs Gain (Loss) [Table] Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Inputs Gain (Loss) [Table] Summarization of information required and determined to be disclosed concerning assets and liabilities, including [financial] instruments, which are measured at fair value on a recurring basis using significant unobservable inputs (Level 3). Deferred income taxes Deferred Income Tax Assets, Net Net change in cash Net Change In Cash Proceeds Managed Collateral The net change in cash from the proceeds managed related to collateral received in conjunction with the entity's securities lending and over-the-counter derivatives. Protection Services Service Business [Member] Service Business [Member] Transfers to (from) held for sale Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net Gain (loss) included in earnings Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings Adjustments to liability Restructuring Reserve, Accrual Adjustment Protection plans Protection Plans [Member] Protection Plans Fixed income securities with unrealized loss position greater than or equal to 20% of amortized cost, net Available for sale Securities, Unrealized Losses Having Loss of Twenty Percent or Higher The amount of unrealized losses that are related to securities with an unrealized loss position greater than 20% of cost or amortized cost. Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Schedule of liability for unpaid claims and claims adjustment expense Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block] General [Abstract] General [Abstract] General [Abstract] Dividends paid on common stock Payments of Ordinary Dividends, Common Stock National Flood Insurance Program National Flood Insurance Program [Member] National Flood Insurance Program Company's pension and postretirement benefit plans Schedule of Defined Benefit Plans Disclosures [Table Text Block] Foreign currency contracts Foreign Exchange Contract [Member] Costs and expenses Benefits, Losses and Expenses [Abstract] Due after ten years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Fair Value Beginning balance Ending balance Liability for Claims and Claims Adjustment Expense Income from discontinued operations, net of tax Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax Total revenues Disposal Group, Including Discontinued Operation, Revenue Fair Value Measurement [Domain] Fair Value Measurement [Domain] Financial Instruments [Domain] Financial Instruments [Domain] Underlying Asset Class [Axis] Underlying Asset Class [Axis] Subsequent acquisition (in percentage) Debt Instrument, Interest Rate, Stated Percentage Individual health Interest Sensitive Life Insurance [Member] Represents interest sensitive life insurance coverage. Additional capital paid-in Additional Paid in Capital, Common Stock Due in one year or less Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Fair Value Pre-close dividend Proceeds From Divestiture Of Interest In Consolidated Subsidiaries, Pre-Close Dividend Proceeds From Divestiture Of Interest In Consolidated Subsidiaries, Pre-Close Dividend Numerator: Numerator [Abstract] Schedule of reductions to costs and expenses due to reinsurance ceded amounts Schedule of Reinsurance Claims Benefits Ceded [Table Text Block] This element may be used as a single block of text to encapsulate entire disclosure, including data and tables for reinsurance claims and benefits ceded. Measurement Input Type [Domain] Measurement Input Type [Domain] Change in Liabilities for Collateral [Roll Forward] Change in Liabilities for Collateral [Roll Forward] Change in Liabilities for Collateral [Roll Forward] Anti-dilutive options excluded from diluted earnings per common share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Document Information [Line Items] Document Information [Line Items] Allstate Health and Benefits Allstate Health and Benefits Allstate Health And Benefits [Member] Allstate Health And Benefits Number of states acquiree operates in Number of States in which Entity Operates Net investment income Property-Liability net investment income Net investment income Net Investment Income Loss contingencies, reasonably possible pretax loss exposure in excess of the amount accrued Loss Contingency Reasonably Possible Additional Losses Pretax Estimate Estimate of the reasonably possible pretax loss exposure in excess of the amount accrued for the entity's lawsuits, regulatory inquiries and other legal proceedings. Net cash provided by operating activities from discontinued operations Cash Provided by (Used in) Operating Activities, Discontinued Operations Equity Component [Domain] Equity Component [Domain] Non-recurring basis Fair Value, Nonrecurring [Member] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Earnings per common share applicable to common shareholders Earnings Per Share Reconciliation [Abstract] Unrealized net capital gains and losses Unrealized net capital gains and losses, after-tax AOCI, Debt Securities, Available-for-Sale, Adjustment, after Tax Income tax benefit Discontinued Operation, Tax Effect of Gain (Loss) from Disposal of Discontinued Operation Equity and index contracts Equity and Index Contract [Member] An equity and index contract. Unrealized foreign currency translation adjustments Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax Schedule of OTC cash and securities collateral pledged Schedule Of Cash And Securities Collateral Pledged [Table Text Block] Schedule Of Cash And Securities Collateral Pledged Total liability derivatives, number of contracts Derivative Liability, Number of Instruments Held Unamortized pension and other postretirement prior service credit Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax Hedging Designation [Domain] Hedging Designation [Domain] Supplemental Cash Flow Information [Abstract] Supplemental Cash Flow Information [Abstract] Fire Fire [Member] Common stock, $.01 par value, 2.0 billion shares authorized and 900 million issued, 266 million and 281 million shares outstanding Common Stock, Value, Outstanding Entity Address, State or Province Entity Address, State or Province Transfers out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers out of Level 3 Accident and health insurance premiums and contract charges Ceded Premiums and Contract Charges Represents the amount of premiums and contract charges related to life insurance, accident and health insurance and annuity contracts that are assumed and earned by another insurer as a result of reinsurance arrangements. Other comprehensive loss, after-tax Other Comprehensive Income (Loss), Net of Tax [Abstract] Short-term investments Available for sale Short-term Investments, Unrealized Gain (Loss) Included in Other Comprehensive Income Available for sale Short-term Investments, Unrealized Gain (Loss) Included in Other Comprehensive Income Due in one year or less Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling within One Year, Amortized Cost Net investment income Net Investment Income [Member] This element represents the location of the gain (loss) included in the Statement of Operations as Net investment income. Measurement input Embedded Derivative Asset (Liability) Net, Measurement Input Due after five years through ten years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Fair Value Gross and net information about the liabilities subject to master netting arrangements Offsetting Assets and Liabilities [Line Items] Transaction [Domain] Transaction [Domain] Fixed income securities Available for sale Fixed Income Securities Unrealized Gain (Loss) Included in Other Comprehensive Income The amount of unrealized gains (losses) included in accumulated other comprehensive income on fixed income securities which are categorized neither as held-to-maturity nor trading securities, as a result of fair value exceeding (under) its amortized cost, as of the balance sheet date. Beginning balance Ending balance Financing Receivable, Allowance for Credit Loss, Excluding Accrued Interest Premiums and other receivables, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Short-term, at fair value (amortized cost $4,031 and $4,009) Short-term investments, at fair value Short-term investments Other Short-Term Investments Total liabilities Liabilities Unearned premiums Increase (Decrease) in Unearned Premiums Fixed income securities with unrealized loss position less than 20% of amortized cost, net Available for sale Securities, Unrealized Losses Having Loss of Less than Twenty Percent The amount of unrealized losses that are related to securities with an unrealized loss position less than 20% of cost or amortized cost. Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Reserve for property and casualty insurance claims and claims expense Reserve for property and casualty insurance claims and claims expense Liability for Claims and Claims Adjustment Expense, Property-Casualty Liability Unrealized net capital gains and losses AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member] Document Type Document Type A A Standard & Poor's, A Rating [Member] Assets Assets, Fair Value Disclosure [Abstract] Increase (decrease) in claims and claims expense Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] Options Equity and Index Contracts Options and Warrants [Member] An investment that follows an index, commodity or basket of assets that trades like stock on an exchange. Non-cash financing activities related to the issuance of shares for vested restricted stock units Stock Issued During Period, Value, Conversion of Units Agent loans Agent Loans [Member] Agent Loans Investments Investments [Abstract] Derivative instruments Derivative Instruments, Unrealized Gain Included in Other Comprehensive Income The amount of unrealized gains included in accumulated other comprehensive income on derivative instruments, as of the balance sheet date. Net Investment Income: Net Investment Income [Line Items] Total gains (losses) included in: net income Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings Other Other investments Other Investments [Member] Debt Securities, Available-for-sale [Table] Debt Securities, Available-for-Sale [Table] Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Table] Michigan Catastrophic Claim Association Michigan Catastrophic Claim Association [Member] Represents the Michigan Catastrophic Claim Association. Total paid Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid Below 1.0 Debt Service Coverage Ratio below 1 [Member] This element represents the information pertaining to mortgage loans on real estate having a debt service coverage ratio below 1. Income Statement Location [Axis] Income Statement Location [Axis] Noncatastrophic Event [Axis] Noncatastrophic Event [Axis] Gross asset fair value of contracts containing credit-risk-contingent features and subject to MNAs Derivative Gross Asset Fair Value with Credit Risk Contingent Features Fair value of derivative asset, presented on a gross basis containing credit risk contingent features and which is subject to master netting arrangements. Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Credit default contracts Credit Default Swap [Member] Gain (loss) on disposition of operations Gain (Loss) on Disposition of Business Write-offs Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff Cumulative Effect, Period of Adoption [Domain] Cumulative Effect, Period of Adoption [Domain] Proceeds from affiliates Proceeds from Divestiture of Interest in Consolidated Subsidiaries Interest cost Defined Benefit Plan, Interest Cost Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities [Abstract] Volume and fair value positions of derivative instruments and location in the Consolidated Statement of Financial Position Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] Total unrealized losses Total unrealized losses Debt Securities, Available-for-Sale, Unrealized Loss Position, Accumulated Loss Restructuring Plan [Domain] Restructuring Plan [Domain] Total return swaps - fixed income Total Return Swap, Fixed Income [Member] Total Return Swap, Fixed Income [Member] Unrealized net holding gains and losses arising during the period, net of related offsets Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Cash to acquire businesses Payments to Acquire Businesses, Gross Schedule of carrying values and fair value estimates of financial instruments not carried at fair value Fair Value, by Balance Sheet Grouping [Table Text Block] Other investments Payments to Acquire Other Investments Pledged to the Company Cash and Securities Pledged as Collateral, from Counterparties This element represents cash and securities pledged as collateral from counterparties. Derivative Contract [Domain] Derivative Contract [Domain] Entity Registrant Name Entity Registrant Name Pension and other postretirement remeasurement (gains) losses Defined Benefit Plan, Remeasurement Gain (Loss) Defined Benefit Plan, Remeasurement Gain (Loss) Reserve for Property-Liability Insurance Claims and Claims Expense [Abstract] Reserve for Property-Liability Insurance Claims and Claims Expense [Abstract] Reserve for Property-Liability Insurance Claims and Claims Expense [Abstract] Preferred stock redemption Stock Redeemed or Called During Period, Value Amortization of deferred gain on reinsurance Disposal Group, Including Discontinued Operation, Gain On Sale Of Subsidiary Stock Disposal Group, Including Discontinued Operation, Gain On Sale Of Subsidiary Stock OTC derivatives Over-the-Counter [Member] Restricted stock units (non-participating) and performance stock awards (in shares) Incremental Common Shares Attributable to Restricted Stock Units Aggregate awards of restricted stock to be issued to an employee under a share-based compensation arrangement considered for purposes of computing diluted earnings per share. Operating cash flow provided Net Cash Provided by (Used in) Operating Activities, Liabilities for Collateral The net operating cash flow provided by (used in) the net change in liabilities for collateral. Total gains (losses) included in: OCI Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Other Comprehensive Income (Loss) Benefit Plans Retirement Benefits [Text Block] ABS Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Fair Value Total equity Balance, beginning of period Balance, end of period Total equity Decrease to equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Maximum amount of additional exposure for contracts with credit-risk-contingent features if all features were triggered concurrently Additional Collateral, Aggregate Fair Value Income tax benefit (expense) on reconciling items Income Tax Expense (Benefit), Reconciling Items Income Tax Expense (Benefit), Reconciling Items Costs and expenses Defined Benefit Plan, Other Operating Costs and Expenses Defined Benefit Plan, Other Operating Costs and Expenses Asset Class [Domain] Asset Class [Domain] Repaid of subordinated notes Repayments of Subordinated Debt Minimum Minimum [Member] Commitments to invest in limited partnership interests Commitments to Invest in Limited Partnership Interests This element represents commitments to acquire financial interests or instruments, to allow for additional participation in certain limited partnership investments. Because the equity investments in the limited partnerships are not actively traded, it is not practical to estimate the fair value of these commitments. Number of counter- parties Number of Counterparties The number of counterparties to which the entity has counterparty credit exposure related to derivative contracts. Entity Emerging Growth Company Entity Emerging Growth Company Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Unrealized net holding gains and losses arising during the period, net of related offsets Other Comprehensive Income (Loss) before Reclassifications, Tax Fair Value of Assets and Liabilities Fair Value Disclosures [Text Block] 2020 Origination, Two Prior Fiscal Years [Member] Origination, Two Prior Fiscal Years Trading Symbol Trading Symbol Entity File Number Entity File Number Liabilities held for sale Liabilities Held For Sale [Member] Liabilities Held For Sale Intersegment premiums and service fees Intersegment Premiums And Service Fees Intersegment Premiums And Service Fees Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Ceded losses incurred Reinsurance Ceded Amount Represents the amount of reinsurance ceded under various contracts. Other liabilities Other Liabilities Counterparty Netting and Collateral Right To Reclaim Cash Offset Other Liabilities Counterparty Netting and Collateral Right To Reclaim Cash Offset Transaction Type [Axis] Transaction Type [Axis] Unrealized net gains (losses) Unrealized Net Gains (Losses) on Investments [Abstract] Less: Comprehensive loss attributable to noncontrolling interest Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Investment Income [Table] Investment Income [Table] (Loss) income from operations before income tax expense Income (Loss) from Operations before Income Tax Expense (Benefit) Sum of operating profit and non-operating income (expense) and income (loss) from equity method investments before income taxes. Loss on disposition of operations Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax Revenues Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract] Noncatastrophic Event [Domain] Noncatastrophic Event [Domain] Futures Interest Rate Financial Futures Contracts [Member] Derivative instrument whose primary underlying risk is tied to the right to receive or pay a sum of money at a given interest rate. Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Balance at the beginning of the period Balance at the end of the period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Cumulative amount incurred to date for active programs Restructuring and Related Cost, Cost Incurred to Date BB and lower Standard Poors BB and Lower Rating [Member] BB and lower rating as defined by the external credit rating agency, Standard and Poor's. Total costs and expenses Disposal Group, Including Discontinued Operation, Total Costs And Expenses Disposal Group, Including Discontinued Operation, Total Costs And Expenses Liability derivatives Derivative Liability [Abstract] Valuation changes included in net income for investments Realized Gain (Loss) on Investments [Table Text Block] Total assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Acquired Including Goodwill Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Acquired Including Goodwill Net change in liabilities Net Change in Liabilities for Collateral [Abstract] Debt Securities, Trading, and Equity Securities, FV-NI [Table] Debt Securities, Trading, and Equity Securities, FV-NI [Table] Schedule of business segments revenue disclosures Schedule of Business Segments Revenue Disclosure [Table Text Block] The schedule of revenues by segment. Earnings per common share applicable to common shareholders - Basic (in dollars per share) Earnings Per Share, Basic Total credit losses by asset type Allowance for Credit Loss, Credit Loss By Asset Type Allowance for Credit Loss, Credit Loss By Asset Type Other liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Liabilities Less: reclassification adjustment of realized capital gains and losses Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Accounting Standards Update and Change in Accounting Principle [Table] Accounting Standards Update and Change in Accounting Principle [Table] Fixed income securities, at fair value, amortized cost Amortized cost, net Debt Securities, Available-for-Sale, Amortized Cost, Excluding Accrued Interest, after Allowance for Credit Loss Nationwide Aggregate Reinsurance Program Nationwide Aggregate Reinsurance Program [Member] Nationwide Aggregate Reinsurance Program Real estate Real Estate Loan [Member] Mortgage loans Payments to Purchase Mortgage Loans The cash outflow used to purchase loans that are secured with real estate mortgage. Derivative Instruments, Gain (Loss) Derivative Instruments, Gain (Loss) [Line Items] Entity Interactive Data Current Entity Interactive Data Current Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Property-Liability Property Liability [Member] Property-liability segment includes the Allstate Protection and the discontinued lines and coverage segments. Property and casualty insurance premiums earned Ceded Premiums Earned Changes in: Increase (Decrease) in Operating Capital [Abstract] Futures Equity and Index Contracts Financial Futures Contracts [Member] Derivative instrument whose primary underlying risk is tied to share prices for financial futures contracts. Preferred stock and additional capital paid-in, $1 par value, 25 million shares authorized, 81.0 thousand shares issued and outstanding, $2,025 aggregate liquidation preference Preferred Stock, Including Additional Paid in Capital Portion at Fair Value Measurement Portion at Fair Value Measurement [Member] Internal Credit Assessment [Domain] Internal Credit Assessment [Domain] Limited partnership interests Limited partnership interests carried at fair value Fair Value Partnership Interest [Member] Shares reissued under equity incentive plans, net Proceeds (Payments), Issuance of Shares, Share-based Payment Arrangement, Including Option Exercised Proceeds (Payments), Issuance of Shares, Share-based Payment Arrangement, Including Option Exercised Shares reissued under equity incentive plans, net Shares Issued, Value, Share-Based Payment Arrangement, after Forfeiture Treasury stock purchases Payments for Repurchase of Common Stock Class of Stock [Axis] Class of Stock [Axis] National General Holdings Corp. National General National General Holdings Corp. [Member] National General Holdings Corp. Less than 12 months Less than Twelve Months [Abstract] Document Quarterly Report Document Quarterly Report Valuation change and settlements of derivatives Gain (Loss) on Derivative Instruments, Net, Pretax Remaining program charges Restructuring and Related Cost, Expected Cost Remaining Valuation change of equity investments Equity Securities, FV-NI, Realized Gain (Loss) NAIC 4 / B Standard & Poor's, B Rating [Member] Retained income Retained Earnings (Accumulated Deficit) Future work environment Future Work Environment [Member] Future Work Environment Transfers into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3 Remeasurement of plan assets Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement External Credit Rating by Grouping [Axis] External Credit Rating by Grouping [Axis] Total Level 3 gains (losses) included in net income Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings [Abstract] Scenario [Domain] Scenario [Domain] Recurring basis Fair Value, Recurring [Member] Securities collateral (received) pledged Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Security Not Offset Fair value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months Reinsurance and indemnification recoverables, net Reinsurance recoverables, net Reinsurance and indemnification recoverables, net Reinsurance And Indemnification Recoverables, Net Reinsurance And Indemnification Recoverables, Net Document Fiscal Year Focus Document Fiscal Year Focus Cash classified as assets held for sale at beginning of period Less: Cash classified as assets held for sale at end of period Disposal Group, Including Discontinued Operation, Cash Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Operating cash flow (used) Net Cash Provided by Used in Operating Activities Proceeds Managed Collateral The net operating cash flow provided or used related to collateral received in conjunction with the entity's securities lending and over-the-counter derivatives. Operating costs and expenses Other Cost and Expense Operating [Member] This element represents the location of the gain (loss) included in the Statement of Operations as Operating costs and expenses. Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Table] Definitive agreement with Wilton Reassurance Disposal Group, Including Discontinued Operation, Consideration Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Corporate - public Corporate - public Corporate Debt Securities, Public [Member] Corporate Debt Securities, Public [Member] Due after ten years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 10 Years, Amortized Cost Carrying value of non-impaired fixed and variable rate mortgage loans by debt service coverage ratio distribution Financing Receivable Credit Quality Indicators [Table Text Block] Mortgage loans Proceeds from Collection of Mortgage Loans The cash inflow from collections of repayments from borrowers on loans that are secured with real estate mortgages. Remeasurement of plan assets (gains) losses Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Remeasurement Plan Assets Gain (Loss) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Remeasurement Plan Assets Gain (Loss) Total derivatives, fair value, net Derivative, Fair Value, Net Credit default swaps – buying protection Credit Default Swap, Buying Protection [Member] Southern California Edison Southern California Edison [Member] Southern California Edison [Member] Document Information [Table] Document Information [Table] Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Limited partnership interests Limited partnership interests Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Goodwill Goodwill Notes payable Notes Payable Income tax (benefit) expense Income Tax Expense (Benefit) Deferred income taxes Deferred Income Tax Liabilities, Net Deferred policy acquisition costs Increase (Decrease) in Deferred Policy Acquisition Costs Discount rate Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Change in Weighted Average Discount Rate Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Change in Weighted Average Discount Rate Assets held for sale Assets Held For Sale [Member] Assets Held For Sale Net (increases) decreases related to credit losses previously reported Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Not Previously Recorded Net amount on balance sheet Net amount on balance sheet Derivative Liability Liability derivatives gross amount Gross amount Derivative Liability, Subject to Master Netting Arrangement, before Offset Amortized cost, net Debt Securities, Available-for-Sale, Amortized Cost, Rolling Maturity [Abstract] Limited partnership interests Proceeds from Divestiture of Interest in Limited Partnership Interest Proceeds from Divestiture of Interest in Limited Partnership Interest Other investments Other Investments, Gross Asset and Right to Reclaim Cash, Offset Other Investments, Gross Asset and Right to Reclaim Cash, Offset Total investments Investments Discontinued operations (in dollars per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Preferred stock par value Preferred Stock [Member] Senior Notes Senior Notes [Member] Counterparty and cash collateral netting Derivative Liability Counterparty Netting and Collateral Right To Reclaim Cash Offset Represents the amount of counterparty netting and the amount of right to receive cash collateral under master netting arrangements offset against derivative liabilities. Discontinued Operations, Held-for-sale Discontinued Operations, Held-for-sale [Member] Credit Derivatives Contract Type [Domain] Credit Derivatives Contract Type [Domain] Deferred policy acquisition costs Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Cash from continuing operations at beginning of period Cash from continuing operations at end of period Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents Unrealized foreign currency translation adjustments Change in unrealized foreign currency translation adjustments Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Municipal Not Rated by Third Party Credit Rating Agencies Municipal Not Rated by Third Party Credit Rating Agencies [Member] Represents the municipal securities not rated by third party credit rating agencies. Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases Net (loss) income from continuing operations applicable to common shareholders Net Income (Loss) from Continuing Operations Available to Common Shareholders, Basic Bank loans Bank Loans Categorized under Other Investments Represents the portion of other investments categorized as bank loans, as of the balance sheet date. Issues Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Issuances Schedule of gross unrealized losses and fair value of available for sale securities by length of time Unrealized Gain (Loss) on Investments [Table Text Block] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Subtotal Available for sale Securities, Debt Maturities with Single Maturity Date Fair Value This item represents the total of all debt securities grouped by maturity dates excluding asset-backed securities, residential mortgage-backed securities and commercial mortgage-backed securities, at fair value, which are classified neither as held-to-maturity nor trading securities. Accident, health and other policy benefits Accident And Health Insurance Contract Benefits, Net of Reinsurance Recoveries Accident And Health Insurance Contract Benefits, Net of Reinsurance Recoveries Asset derivatives Derivative Asset [Abstract] NAIC 3 / BB Standard & Poor's, BB Rating [Member] Income Statement Location [Domain] Income Statement Location [Domain] Amendment Flag Amendment Flag Investment Type [Axis] Investment Type [Axis] Other comprehensive loss, after-tax Other Comprehensive Income (Loss), Net of Tax Acquisitions and Dispositions Mergers, Acquisitions and Dispositions Disclosures [Text Block] Total liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Gross unrealized, Gains Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Gain, before Tax Less: Preferred stock dividends Less: Preferred stock dividends Preferred Stock Dividends, Income Statement Impact Deferred tax liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Claims and claims expense paid related to: Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid [Abstract] Fixed income securities, at fair value (amortized cost, net $45,468 and $41,376) Total fixed income securities Fixed income securities Total Debt Securities, Available-for-Sale, Excluding Accrued Interest Schedule of gains and losses included in net income for Level 3 assets and liabilities still held at the balance sheet date Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Table Text Block] Total included in net income Fair Value Assets and Liabilities Measured on Recurring Basis Change in Unrealized Gain (Loss) Included in Earnings This item represents the amount of the total change in unrealized (holding) gains or losses for the period which are included in the statement of income (or changes in net assets). Such unrealized (holding) gains or losses relate to those assets and liabilities still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3). National General acquisition as of January 4, 2021 Liability for Unpaid Claims and Claims Adjustment Expense, Business Acquisitions Counterparty Name [Axis] Counterparty Name [Axis] Below investment grade fixed income securities Below investment grade fixed income securities Below Investment Grade Fixed Income Securities [Member] Below investment grade is defined as a security not meeting the criteria for investment grade securities. Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Total derivatives, Number of contracts Derivative, Number of Instruments Held Number of  issues Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Number of Positions Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Net amount Derivative Asset, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Supplemental Cash Flow Information Cash Flow, Supplemental Disclosures [Text Block] Operating lease, payments Operating Lease, Payments Redemption and repayment of long-term debt Repayments of Long-Term Debt External Credit Rating by Grouping [Domain] External Credit Rating by Grouping [Domain] Claim payments outstanding Claim Payments Outstanding Liability as of the balance sheet date for benefit claims that have been paid but the payment has not yet cleared. Unamortized pension and other postretirement prior service credit Change in unamortized pension and other postretirement prior service credit Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Life premiums and contract charges Disposal Group, Including Discontinued Operation, Premium And Contract Charges Disposal Group, Including Discontinued Operation, Premium And Contract Charges 2018 Origination, Four Prior Fiscal Years [Member] Origination, Four Prior Fiscal Years Decrease in unrealized net capital gains and losses, after-tax OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment and Tax Common stock, shares authorized (in shares) Common Stock, Shares Authorized Schedule of Guarantor Obligations [Table] Schedule of Guarantor Obligations [Table] NAIC 2 / BBB BBB Standard & Poor's, BBB Rating [Member] Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Maximum Maximum [Member] Preferred stock additional capital paid-in Preferred Stock Including Additional Paid in Capital [Member] Effects of Reinsurance [Table] Effects of Reinsurance [Table] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Investment grade fixed income securities Investment grade fixed income securities Investment Grade Fixed Income Securities [Member] Investment grade is defined as a security having a rating from the National Association of Insurance Commissioners ("NAIC") of 1 or 2; a rating of Aaa, Aa, A or Baa from Moody's, a rating of AAA, AA, A or BBB from Standard and Poor's, Fitch or Dominion, or aaa, aa, a or bbb from A.M. Best; or a comparable internal rating if an externally provided rating is not available. Business Acquisition [Line Items] Business Acquisition [Line Items] Measurement Frequency [Domain] Measurement Frequency [Domain] Reserve for future policy benefits Liability for Future Policy Benefit, before Reinsurance Net (loss) income from continuing operations Net (loss) income from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Total recurring Level 3 assets Fair Value Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Earnings This item represents the amount of the total change in unrealized (holding) gains or losses for the period which are included in the statement of income (or changes in net assets). Such unrealized (holding) gains or losses relate to those assets still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3). 1.26 - 1.50 Debt Service Coverage Ratio below 1.26 to 1.5 [Member] This element represents the information pertaining to mortgage loans on real estate having a debt service coverage ratio between 1.26 to 1.5. Reserve for property and casualty insurance claims and claims expense Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Liability for Claims and Claims Adjustment Expense, Property Casualty Liability Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Liability for Claims and Claims Adjustment Expense, Property Casualty Liability Fixed income securities Payments to Acquire Debt Securities, Available-for-Sale Forward contract on accelerated share repurchase agreement Adjustments to Additional Paid in Capital Forward Contract on Accelerated Share Repurchase Agreement Amount of increase (decrease) to additional paid in capital (APIC) resulting from changes in forward contract on accelerated share repurchase agreement. Expense incurred Increase (Decrease) in Restructuring Reserve ABS Debt Securities, Available-for-Sale, Maturity, without Single Maturity Date, Amortized Cost Income from discontinued operations before income tax expense Income (loss) from discontinued operations Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax Title of 12(b) Security Title of 12(b) Security Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Fixed income securities Fixed income securities Fixed Income Securities [Member] Catastrophic Event [Axis] Catastrophic Event [Axis] Short-term investments Short-term investments Short-Term Investments Transfers to (from) held for sale Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Transfers, Net Other revenue Product and Service, Other [Member] Homeowners Homeowners Home Owners [Member] Represents homeowners insurance to individuals in United States and Canada. Unrealized losses Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss Guarantees and Contingent Liabilities Commitments Contingencies and Guarantees [Text Block] Reportable Segments Segment Reporting Disclosure [Text Block] Beginning balance Ending balance Fixed income securities Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward] Reinsurance Recoverable, Allowance for Credit Loss [Roll Forward] Unrealized losses Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss Fair value Estimate of Fair Value Measurement [Member] Commercial lines Commercial lines Property and Casualty, Commercial Insurance [Member] Policy loans Policy Loans [Member] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Current year Current Year Claims and Claims Adjustment Expense Fair value Debt Securities, Available-for-Sale, Maturity, Fair Value, Rolling Maturity [Abstract] Gross liability fair value of contracts containing credit-risk-contingent features Derivative Gross Liability Fair Value with Credit Risk Contingent Features Fair value of derivative liabilities, presented on a gross basis containing credit risk contingent features. Credit Rating, Standard & Poor's [Axis] Credit Rating, Standard & Poor's [Axis] Equity securities, at fair value, cost Equity Securities, FV-NI, Cost Continuing operations (in dollars per share) Income (Loss) from Continuing Operations, Per Basic Share Offsetting Assets and Liabilities [Table] Offsetting Assets and Liabilities [Table] Disclosure of information about derivative and financial assets and liabilities that are subject to offsetting, including enforceable master netting arrangements. Protection Services Protection Services [Member] Protection Services Weighted average common shares - Basic (in shares) Weighted average common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic 12 months or more Twelve Months or More [Abstract] Roadside assistance Roadside Assistance [Member] Roadside Assistance [Member] Schedule of variable interest entities Schedule of Variable Interest Entities [Table Text Block] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Schedule of change in unrealized net capital gains and losses Schedule of Change in Unrealized Net Capital Gains and Losses [Table Text Block] This item represents the schedule of change in unrealized net capital gains and losses by type of securities. Prior years Prior Year Claims and Claims Adjustment Expense Credit default swaps – selling protection Credit Default Swap, Selling Protection [Member] CHICAGO STOCK EXCHANGE, INC NYSE CHICAGO, INC. [Member] Florida Excess Catastrophe Reinsurance Program Florida Excess Catastrophe Reinsurance Program [Member] Florida Excess Catastrophe Reinsurance Program Total derivatives, notional amount Notional amount Derivative, Notional Amount Schedule of realized capital gains and losses by transaction type Schedule of Gain (Loss) on Investments by Transaction Type [Table Text Block] This item represents the schedule of realized gains and losses reported in the statement of income by type of transactions. Non-catastrophe losses Non Catastrophe Reestimates [Member] Represents adjustments to the reserves for unpaid claims and claims adjustment expense resulting from non-catastrophe loss re-estimates. Total Realized Gain (Loss), Fair Value Recognized In Net Income Realized Gain (Loss), Fair Value Recognized In Net Income Nationwide Catastrophe Reinsurance Program Nationwide Catastrophe Reinsurance Program [Member] Nationwide Catastrophe Reinsurance Program Total gains (losses) included in: OCI Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Significant unobservable inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Restructuring and Related Activities [Abstract] Restructuring and Related Activities [Abstract] Allstate Protection All State Protection [Member] Allstate Protection comprises two brands, the Allstate brand and Encompass brand. Noncontrolling interest Noncontrolling Interest [Member] Due after five years through ten years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after 5 through 10 Years, Amortized Cost Short-term, at fair value, amortized cost Other Short Term Investments, Amortized Cost The amortized cost of short-term investments, net of adjustments for other-than-temporary impairments, if any. Diluted Diluted Earnings Per Share, Diluted [Abstract] Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements Organization, Consolidation and Presentation of Financial Statements [Abstract] Disposal Group Name [Domain] Disposal Group Name [Domain] Shelter-in-Place Payback expense Policyholder Benefits, Shelter-in-Place Payback Policyholder Benefits, Shelter-in-Place Payback Issues Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Issuances Counterparty credit exposure by counterparty credit rating Schedule of Derivative Counterparty Credit Exposure [Table Text Block] Schedule of counterparty credit exposure by counterparty credit rating. Significant other observable inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Current Fiscal Year End Date Current Fiscal Year End Date Purchases Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases Property and casualty insurance premiums Property, Liability and Casualty Insurance Product Line [Member] Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other Gain on sale of headquarters Gain (Loss) on Disposition of Property Plant Equipment Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Calculation Rollforward Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Equity incentive plans activity APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Other investments Proceeds from Sale of Other Investments Reinsurance payable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Reinsurance Payable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Reinsurance Payable Net balance as of January 1 Net balance as of September 30 Liability for Unpaid Claims and Claims Adjustment Expense, Net Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] A+ Standard & Poor's, A+ Rating [Member] 2021 Origination, Prior Fiscal Year [Member] Origination, Prior Fiscal Year Foreign government Debt Security, Government, Non-US [Member] Change in short-term and other investments, net Payments for (Proceeds from) Short-Term Investments Reinsurance and Indemnification Reinsurance [Text Block] Collateral posted under MNAs for contracts containing credit-risk contingent features Collateral posted under MNAs for contracts containing credit-risk-contingent features Collateral Already Posted, Aggregate Fair Value Net amount Derivative Liability, Including Not Subject to Master Netting Arrangement, after Offset and Deduction Unfavorable reestimates Prior Year Claims and Claims Adjustment Expense, Unfavorable Reestimates Prior Year Claims and Claims Adjustment Expense, Unfavorable Reestimates Credit losses Fixed income securities Allowance for Credit Loss, Credit Loss Recognized In Net Income Allowance for Credit Loss, Credit Loss Recognized In Net Income Other Proceeds from (Payments for) Other Financing Activities Financial assets Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract] Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Incurred expense (adjustment) Total incurred Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims AA Standard & Poor's, AA Rating [Member] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative Instruments and Hedging Activities Disclosure [Abstract] Exchange [Domain] Exchange [Domain] Other contracts Other Contract [Member] Other unrealized net capital gains and losses, pre-tax Increase (Decrease) Other Unrealized Net Capital Gains And Losses, Pre-tax Increase (Decrease) Other Unrealized Net Capital Gains And Losses, Pre-tax Schedule of supplemental cash flow information from collateralized securities received Schedule of Supplemental Cash Flow Information from Collateralized Securities Received [Table Text Block] This element may be used to capture the complete disclosure pertaining to supplemental cash flow information about collateral received. Liability for collateral Liabilities for collateral, beginning of period Liabilities for collateral, end of period Obligation to Return Collateral Securities Lending and Derivatives The liability to return cash and securities received as collateral in conjunction with securities lending and over-the-counter derivatives. Entity Tax Identification Number Entity Tax Identification Number Derivatives, Fair Value Derivatives, Fair Value [Line Items] Investments [Table] Schedule of Investments [Table] Equity securities Proceeds from Sale of Equity Securities, FV-NI Schedule of Credit Derivatives [Table] Schedule of Credit Derivatives [Table] Reinsurance Disclosures [Abstract] Reinsurance Disclosures [Abstract] Consolidated Entities [Domain] Consolidated Entities [Domain] Derivative instruments Derivative Instruments, Unrealized Loss Included in Other Comprehensive Income The amount of unrealized losses included in accumulated other comprehensive income on derivative instruments, as of the balance sheet date. Net increase in cash, including cash classified as assets held for sale Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Schedule of restructuring programs Restructuring and Related Costs [Table Text Block] Operating costs and expenses Disposal Group, Including Discontinued Operation, Operating Costs And Expenses Disposal Group, Including Discontinued Operation, Operating Costs And Expenses Denominator: Denominator [Abstract] Entity Central Index Key Entity Central Index Key Pre-tax Other Comprehensive Income (Loss), before Tax [Abstract] Other comprehensive income (loss) on a pre-tax and after-tax basis Comprehensive Income (Loss) [Table Text Block] Measurement Input Type [Axis] Measurement Input Type [Axis] Proceeds from sales Proceeds from Sale of Investments [Abstract] City Area Code City Area Code Assets Assets Assets [Abstract] Other operating assets and liabilities Increase (Decrease) in Other Operating Assets and Liabilities, Net Amounts recognized for: Amount Recognized in Unrealized Net Capital Gains and Losses [Abstract] Holland Hewitt v. Allstate Life Insurance Company Holland Hewitt v. Allstate Life Insurance Company [Member] Holland Hewitt v. Allstate Life Insurance Company Contractholder fund withdrawals Withdrawal from Contract Holders Funds Reinsurance recoverables, net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Reinsurance Recoverables, Net Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Reinsurance Recoverables, Net Increase in the provision for credit losses Reinsurance Recoverable, Allowance for Credit Loss, Period Increase (Decrease) Fair value Financial Liabilities Fair Value Disclosure Asset Class [Axis] Asset Class [Axis] Earnings per common share Earnings Per Share, Policy [Policy Text Block] Preferred stock, value aggregate liquidation preference Preferred Stock, Liquidation Preference, Value Less recoverables Plus recoverables Reinsurance Recoverables, Incurred but Not Reported Claims Interest rate contracts Interest Rate Contract [Member] Investment purchases Payments to Acquire Investments [Abstract] Purchases of property and equipment, net Payments to Acquire Property, Plant, and Equipment Weighted Average Weighted Average [Member] Other liabilities and accrued expenses Other Liabilities And Accrued Expenses Other Liabilities And Accrued Expenses Computation of basic and diluted earnings per common share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] ROU asset obtained in exchange for operating lease liability Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Gross realized losses Debt Securities, Available-for-Sale, Realized Loss Unearned premiums Unearned premiums Unearned Premiums Postretirement benefits Other Postretirement Benefits Plan [Member] Less: reclassification adjustment of realized capital gains and losses Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Due after one year through five years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Amortized Cost Increase (decrease) in equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Net (loss) income Net (loss) income Net income (loss) Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Variable Interest Entity, Primary Beneficiary Variable Interest Entity, Primary Beneficiary [Member] Deferred acquisition costs (value of business acquired) Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Acquisition Costs Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Acquisition Costs Entity Address, Postal Zip Code Entity Address, Postal Zip Code Reductions to costs and expenses due to reinsurance ceded amounts Reinsurance Claims Benefits Ceded [Abstract] Total Investments, Fair Value Disclosure Mortgage loans amortized cost by debt service coverage ratio distribution and year of origination Mortgage loans amortized cost by debt service coverage ratio distribution and year of origination [Table Text Block] Mortgage loans amortized cost by debt service coverage ratio distribution and year of origination [Table Text Block] Contractholder funds on investment contracts Contractholder Funds on Investment Contracts Represents contract holder funds on investment contracts as of the balance sheet date. Restructuring liability as of December 31, 2021 Restructuring liability as of September 30, 2022 Restructuring Reserve Foreign currency forwards Foreign Currency Forwards [Member] Represents information pertaining to contracts negotiated between two parties to purchase and sell a specific quantity of foreign currency at a price specified at origination of the contract, with delivery and settlement at a specified future date. Accident and health insurance premiums and contract charges Life and Annuity Insurance Product Line [Member] Costs and expenses Disposal Group, Including Discontinued Operation, Costs and Expenses [Abstract] Disposal Group, Including Discontinued Operation, Costs and Expenses Offsets-Cash collateral received Derivative Asset, Subject to Master Netting Arrangement, Collateral, Obligation to Return Cash, Offset Against Derivative Asset Portfolio composition Summary Investment Holdings [Table Text Block] Net gains (losses) on investments and derivatives Net gains (losses) on investments and derivatives Realized Capital Gains and Losses [Member] This element represents the location of the gain (loss) included in the Statement of Operations as Realized capital gains and losses. Received by the Company Margin Deposit Liabilities Margin Deposit Liabilities Other Payments for (Proceeds from) Other Investing Activities Statistical Measurement [Domain] Statistical Measurement [Domain] Bank loans amortized cost by credit quality and year of origination Bank loans amortized cost by credit quality and year of origination [Table Text Block] Bank loans amortized cost by credit quality and year of origination [Table Text Block] Derivative instruments with credit features in a liability position, including fair value of assets and collateral netted against the liability Schedule of Derivative Instruments Credit Features in Liability Position and Netting [Table Text Block] Schedule of fair value of derivative instruments with termination, cross-default or collateral credit-risk-contingent features that are in a liability position and the fair value of assets and collateral that are netted against the liability. Pension net cost (benefit) Defined Benefit Plan, Net Periodic Benefit Cost (Credit) Schedule of unrealized net capital gains and losses Schedule of Unrealized Capital Gains and Losses Included in Accumulated Other Comprehensive Income [Table Text Block] This item represents the schedule of unrealized net capital gains and losses recorded in accumulated other comprehensive income by type of securities. Fixed Income Securities Valued Based on Nonbinding Broker Quotes Fixed Income Securities Valued Based on Nonbinding Broker Quotes [Member] Represents the fixed income securities valued based on non-binding broker quotes. Shares acquired Treasury Stock, Value, Acquired, Cost Method Net (loss) income attributable to Allstate Net Income (Loss) Attributable to Parent Contingent consideration Contingent Consideration Derivative [Member] Contingent Consideration Derivative Cumulative Effect, Period of Adoption [Axis] Cumulative Effect, Period of Adoption [Axis] Amortization of prior service credit Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Gross unrealized Gains Gross Unrealized Gains [Abstract] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Unrealized net capital gains and losses Change in unrealized net capital gains and losses Other Comprehensive Income (Loss), Available for Sale Securities, Including Other than Temporary Impairment Losses Adjustment Net of Tax Net of tax amount of the appreciation (loss) in the value of unsold available-for-sale securities. Includes amounts related to other than temporary impairment (OTTI) losses. Total asset derivatives, number of contracts Derivative Asset, Number of Instruments Held Sales Debt Securities, Gain (Loss) Scenario [Axis] Scenario [Axis] Assets at fair value Total assets at fair value Assets, Fair Value Disclosure Restructuring Plan [Axis] Restructuring Plan [Axis] Exposure, net of collateral Credit Derivative Exposure Net of Collateral The amount of credit exposure by counterparties net of collateral received, related to derivative contracts. Debt and Equity Securities, FV-NI [Line Items] Debt and Equity Securities, FV-NI [Line Items] Municipal US States and Political Subdivisions Debt Securities [Member] Treasury stock, at cost (634 million and 619 million shares) Treasury Stock, Common, Value Contractholder funds Policyholder Contract Deposit Effect of dilutive potential common shares Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Continuing operations (in dollars per share) Income (Loss) from Continuing Operations, Per Diluted Share Derivative Instrument [Axis] Derivative Instrument [Axis] Offsets-Cash collateral (received) pledged Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Cash Offset Schedule of the rollforward of Level 3 assets and liabilities held at fair value on a recurring basis Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation [Table Text Block] This element represents, for the fair value measurement of assets and liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issuances, and settlements (net); and (3) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs). Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] 5.100% Fixed-to-Floating Rate Subordinated Debentures due 2053 Subordinated Debentures Due 2053 at 5.10 Percent [Member] Represents the subordinated debentures due in 2053 at an interest rate of 5.10 percent. Quoted prices in active markets for identical assets (Level 1) Fair Value, Inputs, Level 1 [Member] Other assumptions Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Change in Other Assumptions Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Change in Other Assumptions Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales Credit exposure Counterparty Credit Exposure The amount of credit exposure by counterparties related to derivative contracts. Business combination expenses and amortization of purchased intangibles Business Combination, Acquisition Related Costs, After-Tax Business Combination, Acquisition Related Costs, After-Tax Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss) Change in Unrealized Gain (Loss) Recognized in Accumulated Other Comprehensive Income (Loss) [Line Items] Deferred income taxes Deferred Income Taxes Recognized in Accumulated Other Comprehensive Income Accumulated adjustment to deferred income taxes related to unrealized capital gains and losses, as of the balance sheet date. New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Series H Preferred Stock Series H Preferred Stock [Member] Net amount on balance sheet Net amount on balance sheet Derivative Asset Schedule for fixed income securities at amortized cost, gross unrealized gains and losses and fair value Debt Securities, Available-for-Sale [Table Text Block] Settlements Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Other liabilities Other Liabilities Due after one year through five years Debt Securities, Available-for-Sale, Maturity, Allocated and Single Maturity Date, Rolling after One Through Five Years, Fair Value Expected program charges Restructuring and Related Cost, Expected Cost Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Schedule of business segments net income disclosures Schedule of Business Segments Net Income (Loss) Disclosure [Table Text Block] The schedule of net income (loss) by segment. Liability Class [Axis] Liability Class [Axis] Entity Listings, Exchange [Axis] Entity Listings, Exchange [Axis] Changes in unrealized net capital gains and losses reported in OCI Debt Securities, Available-for-Sale, Gain (Loss) Pledged by the Company Securities Pledged as Collateral to Counterparties This element represents securities pledged to counterparties as collateral for credit exposure. Write-offs Reinsurance, Loss on Uncollectible Accounts in Period, Amount Cash Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Prior years Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years Dividends on preferred stock Dividends, Preferred Stock, Cash Securities collateral (received) pledged Derivative Liability, Subject to Master Netting Arrangement, Collateral, Right to Reclaim Security Not Offset Fair Value Assets Measured on Recurring Basis Unobservable Input Reconciliation Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Activity in the reserve for property-liability insurance claims and claims expense: Liability for Unpaid Claims and Claims Adjustment Expense, Net [Roll Forward] Gains (losses) included in net income for Level 3 assets and liabilities: Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Inputs Gain (Loss) [Line Items] Preferred stock, shares issued (in shares) Preferred Stock, Shares Issued Loss on disposition of operations, net of tax Gain (Loss) on Disposition of Stock in Subsidiary Restructuring Type [Axis] Restructuring Type [Axis] Segments [Axis] Segments [Axis] Insurance Product Line [Domain] Product and Service [Domain] Proceeds from sale of headquarters Proceeds from Sale of Buildings Entity Shell Company Entity Shell Company Schedule of net investment income Investment Income [Table Text Block] Realized capital gains and losses by asset type Gain (Loss) on Securities [Line Items] Amortization of deferred gain on reinsurance Amortization Of Deferred Gain On Reinsurance Amortization Of Deferred Gain On Reinsurance NAIC 5-6/ CCC and below Standard & Poor's, CCC- Rating [Member] Financial Instrument [Axis] Financial Instrument [Axis] Other investments, net Other investments, net Other investments Other Investments Tax Other Comprehensive Income (Loss), Tax [Abstract] Redemption of preferred stock Proceeds from (Repurchase of) Redeemable Preferred Stock Consolidation Items [Domain] Consolidation Items [Domain] Subsequent Event Subsequent Event [Member] Document Period End Date Document Period End Date Origination Period [Domain] Origination Period [Domain] Origination Period [Domain] Total assets Assets Earnings per common share applicable to common shareholders Earnings Per Share [Abstract] Unrealized net capital gains and losses, pre-tax Total Unrealized Gains (Losses) on Investments before Taxes The amount of unrealized gain (loss) before taxes on all investment securities, which are included in accumulated other comprehensive income (loss), as a result of fair value exceeding (under) its cost, as of the balance sheet date. Deferred income taxes OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, Tax Schedule of assets and liabilities that are measured at fair value on a recurring and non-recurring basis Fair Value Measurements, Recurring and Nonrecurring [Table Text Block] Pledged by the Company Margin Deposit Assets Equity securities, at fair value (cost $4,652 and $6,016) Equity securities, at fair value Equity securities Equity Securities, FV-NI, Current Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] ABS Asset-Backed Securities [Member] Segments [Domain] Segments [Domain] Dividends paid on preferred stock Payments of Ordinary Dividends, Preferred Stock and Preference Stock Earnings per Common Share Earnings Per Share [Text Block] Unpaid losses estimated (including IBNR) Reinsurance Recoverable for Unpaid Claims and Claims Adjustments Underwriting income (loss) Underwriting Gain (Loss) A measure that is not based on GAAP, which is calculated as premiums earned, less claims and claims expense ("losses"), amortization of deferred policy acquisition costs ("DAC"), operating costs and expenses and restructuring and related charges, as determined using GAAP. Investments [Line Items] Schedule of Investments [Line Items] Disposal Group, Disposed of by Sale, Not Discontinued Operations Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Comprehensive (loss) income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Short-term investments Short-Term Investments [Member] Subtotal Available for sale Securities, Debt Maturities with Single Maturity Date Amortized Cost This item represents the total of all debt securities grouped by maturity dates excluding asset-backed securities, residential mortgage-backed securities and commercial mortgage-backed securities, at cost, net of adjustments made for accretion, amortization, other-than-temporary impairments, and hedging, if any, which are classified neither as held-to-maturity nor trading securities. Origination Period [Axis] Origination Period [Axis] Origination Period Net investment income Disposal Group, Including Discontinued Operation, Net Investment Income Disposal Group, Including Discontinued Operation, Net Investment Income Net cash used in investing activities from discontinued operations Cash Provided by (Used in) Investing Activities, Discontinued Operations Life contract benefits Disposal Group, Including Discontinued Operation, Contract Benefits Disposal Group, Including Discontinued Operation, Contract Benefits Discontinued operations (in dollars per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Mortgage loans Mortgage loans Mortgages [Member] Mortgage loans, net Mortgage loans, net Amortized cost, net Mortgage loans Mortgage Loans on Real Estate, Commercial and Consumer, Net Restructuring Reserve [Roll Forward] Restructuring Reserve [Roll Forward] Equity method of accounting limited partnerships Equity Method Investments Unrealized Loss Included in Other Comprehensive Income The amount of unrealized gains included in accumulated other comprehensive income on equity method investments, as of the balance sheet date. Unrealized foreign currency translation adjustments Accumulated Foreign Currency Adjustment Attributable to Parent [Member] Entity Address, City or Town Entity Address, City or Town Catastrophic Event [Domain] Catastrophic Event [Domain] Intersegment Eliminations Intersegment Eliminations [Member] % of total assets at fair value Assets as Percent of Assets Measured at Fair Value Assets as a percent of total assets measured at fair value on a recurring and non-recurring basis. Noncontrolling interest Stockholders' Equity Attributable to Noncontrolling Interest Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Treasury stock Treasury Stock, Common [Member] Pension benefits Pension Plan [Member] Treasury stock, shares (in shares) Treasury Stock, Common, Shares Less: reclassification adjustment of realized capital gains and losses Reclassification from AOCI, Current Period, Tax Fair Value Net Asset Value Fair Value Measured at Net Asset Value Per Share [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] External Credit Rating, Standard & Poor's [Domain] External Credit Rating, Standard & Poor's [Domain] Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Amortized cost before allowance Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss Total liability derivatives, notional amount Derivative Liability, Notional Amount After-tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Total revenues Consolidated revenues Revenues Carrying value for limited partnership interests Schedule of Investments in and Advances to Affiliates, Schedule of Investments [Table Text Block] Projected option cost Measurement Input, Projected Option Cost [Member] Measurement Input, Projected Option Cost [Member] Number of  issues Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Number of Positions Investments Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Net (loss) income from continuing operations attributable to Allstate Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Fair value Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer Net (increases) decreases related to credit losses Net increases related to credit losses Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Period Increase (Decrease) Amortization of purchased intangibles Amortization of Intangible Assets Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Other assets Other Assets [Member] Unamortized pension and other postretirement prior service credit Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Commitments to fund commercial mortgage loans and bank loans Unfunded Loan Commitments Unfunded Loan Commitments Counterparty Name [Domain] Counterparty Name [Domain] Total Allstate shareholders’ equity Total Allstate shareholders’ equity Stockholders' Equity Attributable to Parent Derivative Financial Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Transfer from investments Transfer from Investments Transfers into Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers Into Level 3 SafeAuto SafeAuto [Member] SafeAuto Other unrealized net capital gains and losses, pre-tax Other Unrealized Net Capital Gains And Losses, Pre-tax Other Unrealized Net Capital Gains And Losses, Pre-tax Embedded derivative financial instruments Embedded Derivative Financial Instruments [Member] Fixed income securities Proceeds from Sale of Debt Securities, Available-for-Sale Accident and health insurance premiums and contract charges Accident and Health Insurance Product Line [Member] Retained income Retained Earnings [Member] Segment Reporting Information Segment Reporting Information [Line Items] Dividends on common stock (declared per share of $0.85, $0.81, $2.55 and $2.43) Dividends, Common Stock, Cash Common Stock, par value $.01 per share Common Stock [Member] Premium installment receivables, net Premium installment and other receivables, net Premiums Receivable, Net Accident and health insurance Allstate Accident And Health [Member] Allstate Accident And Health Net gains (losses) on investments and derivatives Net gains (losses) on investments and derivatives Realized Capital Gains (Losses), Continuing Operations Realized Capital Gains (Losses), Continuing Operations Statement [Table] Statement [Table] Schedule of disposal groups, including discontinued operations Disposal Groups, Including Discontinued Operations [Table Text Block] Acquisition Stock Issued During Period, Value, Acquisitions Equity-indexed and forward starting options in life and annuity product contracts Embedded Derivative Equity Indexed and Forward Starting Options in Life and Annuity Product Contract [Member] Fair value as of the balance sheet date of the embedded derivative Equity Indexed and Forward Starting Options in Life and Annuity Product Contract. Statistical Measurement [Axis] Statistical Measurement [Axis] Other comprehensive income (loss) Other Comprehensive Income (Loss), before Tax Disposal Group Name [Axis] Disposal Group Name [Axis] U.S. government and agencies US Treasury and Government [Member] Equity Components [Axis] Equity Components [Axis] Total included in net income Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss) Litigation Case [Domain] Litigation Case [Domain] AAA Standard & Poor's, AAA Rating [Member] Adjusted net income (loss) Operating Income (Loss) after Tax The operating income (loss), net of tax effect, as measured by the entity for segment reporting purposes. Statement Statement [Line Items] Business combination fair value adjustment Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustments Related to Previous Period Accumulated other comprehensive income: Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Reinsurance Effects of Reinsurance [Line Items] Insurance premiums, commissions and fees Insurance Commissions and Fees Interest credited to contractholder funds Disposal Group, Including Discontinued Operation, Interest Credited To Contract Holder Funds Disposal Group, Including Discontinued Operation, Interest Credited To Contract Holder Funds Gross unrealized, Losses Debt Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, before Tax % of total liabilities at fair value Liabilities as Percent of Liabilities Measured at Fair Value Liabilities as a percent of total liabilities measured at fair value on a recurring and non-recurring basis. Rollforward of credit loss allowance for reinsurance recoverables Reinsurance Recoverable, Allowance for Credit Loss [Table Text Block] Accumulated other comprehensive income Accumlated Other Comprehensive Income AOCI Attributable to Parent [Member] Transfers out of Level 3 Fair Value, Measurement with Unobservable Inputs Reconciliation, Liability, Transfers out of Level 3 Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Policy benefits and other insurance reserves Increase (Decrease) in Future Policy Benefit Reserves and Other Insurance Liabilities Type of Restructuring [Domain] Type of Restructuring [Domain] Document Transition Report Document Transition Report Local Phone Number Local Phone Number Property-liability insurance claims and claims expense Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] Pending accounting standard New Accounting Pronouncements, Policy [Policy Text Block] Operating costs and expenses Other Cost and Expense, Operating Allowance Allowance for Loan and Lease Losses, Real Estate Other investments Proceeds from Maturities, Prepayments and Calls of Other Investments Other liabilities and expenses Accrued Liabilities and Other Liabilities Income tax expense Income tax benefit from discontinued operations Discontinued Operation, Tax Effect of Discontinued Operation Total recurring basis liabilities Liabilities, Fair Value Disclosure Adjustments to reconcile net income (loss) to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Index Index [Member] This element represents the credit derivative index for selling credit protection. Limited partnership interests Payments to Acquire Limited Partnership Interests Income Statement [Abstract] Income Statement [Abstract] Common stock additional capital paid-in Additional Paid-in Capital [Member] Document Fiscal Period Focus Document Fiscal Period Focus Basic Basic Earnings Per Share, Basic [Abstract] Property and casualty insurance claims and claims expense Property Liability Insurance Claims and Claims Expense [Member] This element represents the location of the gain (loss) included in the Statement of Operations as property-liability insurance claims and claims expense. Derivative [Line Items] Derivative [Line Items] Weighted average common shares - Diluted (in shares) Weighted average common and dilutive potential common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Guarantor Obligations [Line Items] Guarantor Obligations [Line Items] Change in unrealized net capital gains and losses OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, before Tax Schedule of Available for Sale Securities Debt Securities, Available-for-Sale [Line Items] Acquisition of operations, net of cash acquired Payments To Acquire Operations Payments To Acquire Operations Pension and other postretirement remeasurement (gains) losses Pension and other postretirement remeasurement gains (losses) Remeasurement (gains) losses Remeasurement (gains) losses Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit Gross realized gains (losses) on sales of fixed income securities Schedule Of Gross Realized Gains (Losses) On Sales Of Fixed Income Securities [Table Text Block] Schedule Of Gross Realized Gains (Losses) On Sales Of Fixed Income Securities [Table Text Block] Credit losses on securities for which credit losses not previously reported Debt Securities, Available-for-Sale, Allowance for Credit Loss, Not Previously Recorded Amortized cost, net Reported Value Measurement [Member] Short-term investments Available for sale Short-term Investments, Unrealized Loss Included in Other Comprehensive Income Available for sale Short-term Investments, Unrealized Loss Included in Other Comprehensive Income Net (gains) losses on investments and derivatives Realized Investment Gains (Losses) Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets [Abstract] Operating Segments Operating Segments [Member] Investments Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Investments Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Investments Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Allstate Life Insurance Company Allstate Life Insurance Company [Member] Allstate Life Insurance Company Less: Net loss attributable to noncontrolling interest Less: Net income (loss) attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest Net (loss) income applicable to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Other Income Other Income [Member] Common stock, shares issued (in shares) Common Stock, Shares, Issued Gross unrealized Losses Gross Unrealized Loss [Abstract] Schedule of other investments by type Schedule of Other Investments, By Type [Table Text Block] Schedule of Other Investments, By Type [Table Text Block] Total unrealized losses Total Unrealized Loss [Abstract] Contractholder fund deposits Additions to Contract Holders Funds Debt Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Long-Term Debt Exit costs Facility Closing [Member] Fair value of assets and liabilities measured on recurring and non-recurring basis Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Net change in proceeds managed Net Change In Proceeds Managed Collateral The net change in the proceeds managed related to collateral received in conjunction with the entity's securities lending and over-the-counter derivatives. Auto Auto Auto [Member] Represents total auto coverage. Net cash (used in) provided by investing activities Net Cash Provided by (Used in) Investing Activities Loss on disposition of operations, net of tax Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax Write-offs Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff Schedule of reinsurance recoverable for paid and unpaid claims Schedule of Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments [Table Text Block] Schedule of Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments [Table Text Block] Corporate and Other Corporate and Other Corporate and Other [Member] Comprehensive (loss) income attributable to Allstate Comprehensive Income (Loss), Net of Tax, Attributable to Parent Litigation Case [Axis] Litigation Case [Axis] Entity Current Reporting Status Entity Current Reporting Status Short-term investments Available for sale Short-term Investments, Unrealized Gain Included in Other Comprehensive Income Available for sale Short-term Investments, Unrealized Gain Included in Other Comprehensive Income Realized capital gains and losses by asset type Other than Temporary Impairment Losses by Asset Type [Line Items] Other than Temporary Impairment Losses by Asset Type Income (loss) from discontinued operations, net of tax Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Payments and non-cash charges Payments for Restructuring Above 1.50 Debt Service Coverage Ratio above 1.5 [Member] This element represents the information pertaining to mortgage loans on real estate having a debt service coverage ratio above 1.5. Employee costs Employee Severance [Member] Investment income, before expense Interest and Dividend Income, Operating Schedule of recognized identified assets acquired and liabilities assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Derivative [Table] Derivative [Table] Series I Preferred Stock Series I Preferred Stock [Member] Series I Preferred Stock Net change in proceeds managed Net Change in Proceeds Managed [Abstract] Series G Preferred Stock Series G Preferred Stock [Member] Sales Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Sales Basis of presentation Basis of Accounting, Policy [Policy Text Block] Liabilities Liabilities Liabilities [Abstract] Property and equipment, net Property, Plant and Equipment, Net Guarantees and Contingent Liabilities Guarantees and Contingent Liabilities Depreciation, amortization and other non-cash items Depreciation, Amortization and Accretion, Net Group health Accident, health and other policy benefits Accident Health and Other [Member] Represents accident, health and other coverage. Total gains (losses) included in: net income Total recurring Level 3 liabilities Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Change in estimated program costs Restructuring And Related Costs, Increase (Decrease) In Expected Cost Remaining Restructuring And Related Costs, Increase (Decrease) In Expected Cost Remaining Long-term debt Long-Term Debt Schedule of credit losses on fixed income securities recognized in earnings Allowance For Credit Loss, Credit Losses Recognized In Earnings [Table Text Block] Allowance For Credit Loss, Credit Losses Recognized In Earnings Fair value Fair Value Securities [Abstract] Company Restructuring Restructuring and Related Activities Disclosure [Text Block] Run-off Property-Liability Run-off Property-Liability Run-Off Property-Liability [Member] Run-Off Property-Liability Derivatives not designated as accounting hedging instruments, total gain (loss) recognized in net income on derivatives Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Restructuring and related charges Disposal Group, Including Discontinued Operation, Restructuring And Related Charges Disposal Group, Including Discontinued Operation, Restructuring And Related Charges Total accumulated other comprehensive income (“AOCI”) Accumulated Other Comprehensive Income (Loss), Net of Tax Fixed income securities Available for sale Fixed Income Securities, Unrealized Loss Included in Other Comprehensive Income Represents the unrealized losses included in accumulated other comprehensive income as of the balance sheet date, for the fixed income securities which are categorized neither as held-to-maturity nor trading securities. Unrealized losses having loss of less than twenty percent Available for sale Securities, Unrealized Losses Having Loss of Less than Twenty Percent, Less than 12 Months Available for sale Securities, Unrealized Losses Having Loss of Less than Twenty Percent, Less than 12 Months Private equity Private Equity [Member] Private Equity [Member] Net change in fixed income securities Net Change in Fixed Income Term Investments of Proceeds Managed Collateral Net Change in Fixed Income Term Investments of Proceeds Managed Collateral Earnings per common share: Earnings Per Share, Attributable to Parent [Abstract] Schedule of realized capital gains and losses by asset type Schedule of Gain (Loss) on Investments by Security Type [Table Text Block] This item represents the schedule of realized gains and losses reported in the statement of income by type of securities. Paid and due from reinsurers and indemnitors Reinsurance Recoverable for Paid Claims and Claims Adjustments Entity Small Business Entity Small Business Measurement Basis [Axis] Measurement Basis [Axis] Dividends (in dollars per share) Common Stock, Dividends, Per Share, Declared Revenues Revenues [Abstract] Amortization of DAC Disposal Group, Including Discontinued Operation, Deferred Policy Acquisition Costs, Amortization Expense Disposal Group, Including Discontinued Operation, Deferred Policy Acquisition Costs, Amortization Expense Property and casualty insurance premiums Premiums Earned, Net Total asset derivatives, notional amount Derivative Asset, Notional Amount Subordinated Debt Subordinated Debt [Member] Other assets Other Assets, Fair Value Disclosure Consolidated Entities [Axis] Consolidated Entities [Axis] Other personal lines Other personal lines Other Personal Lines [Member] Other personal lines include other personal lines that are not separately disclosed. Business Combination and Asset Acquisition [Abstract] Quantitative information about the significant unobservable inputs Fair Value Measurement Inputs and Valuation Techniques [Line Items] Corporate - privately placed Corporate Debt Securities, Private Placement [Member] Corporate Debt Securities, Private Placement [Member] Investments, Debt and Equity Securities [Abstract] Investments, Debt and Equity Securities [Abstract] Term of credit default swaps (in years) Credit Derivative, Term Gain on derivative Derivative, Gain (Loss) on Derivative, Net Internal Credit Assessment [Axis] Internal Credit Assessment [Axis] NEW YORK STOCK EXCHANGE, INC. NEW YORK STOCK EXCHANGE, INC. [Member] Purchase accounting fair value adjustment Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Restructuring and related charges Restructuring and related charges Restructuring Charges Catastrophe Catastrophe [Member] Schedule for fixed income securities based on contractual maturities Investments Classified by Contractual Maturity Date [Table Text Block] Hedging Designation [Axis] Hedging Designation [Axis] Entity Filer Category Entity Filer Category Asset derivatives, gross liability Offset-Counter-party netting Derivative Asset, Subject to Master Netting Arrangement, Liability Offset Equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Schedule of Gain (Loss) on Securities [Table] Schedule of Gain (Loss) on Securities [Table] Allstate Life Insurance Company Of New York Allstate Life Insurance Company Of New York [Member] Allstate Life Insurance Company Of New York Schedule of exchange traded and cleared margin deposits Schedule Of Margin Deposits [Table Text Block] Schedule Of Margin Deposits Accrued interest Schedule Of Accrued Interest [Table Text Block] Schedule Of Accrued Interest Liabilities Liabilities, Fair Value Disclosure [Abstract] Investments reported at NAV Alternative Investment Employer voluntary benefits Traditional Life Insurance [Member] Represents traditional life insurance coverage. Property and casualty insurance claims and claims expense Policyholder Benefits and Claims Incurred, Net, Property, Casualty and Liability Commitments and Contingent Liabilities (Note 12) Commitments and Contingencies Security Exchange Name Security Exchange Name Liability for Unpaid Claims and Claims Adjustment Expense [Table] Liability for Unpaid Claims and Claims Adjustment Expense [Table] Schedule of the activity in the reserve for settling insured claims and expenses incurred in the claims settlement process for the period. Amortization of deferred policy acquisition costs Deferred Policy Acquisition Costs, Amortization Expense Fair Value Balance Sheet Grouping Financial Statement Captions Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Schedule of derivative CDS notional amount by credit rating and fair value of protection sold Schedule of Derivative CDS Notional Amount by Credit Rating and Fair Value of Protection Sold [Table Text Block] Schedule of CDS notional amounts by credit rating and fair value of protection sold. Segment Reconciling Items Segment Reconciling Items [Member] Financial liabilities Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract] Single name Single Name [Member] This element represents the single name identified for selling credit protection. Service cost Defined Benefit Plan, Service Cost 1.0 - 1.25 Debt Service Coverage Ratio below 1 to 1.25 [Member] This element represents the information pertaining to mortgage loans on real estate having a debt service coverage ratio between 1 to 1.25. Reduction of allowance related to sales Finance Receivables, Excluding Accrued Interest, Allowance for Credit Loss, Securities Sold Finance Receivables, Excluding Accrued Interest, Allowance for Credit Loss, Securities Sold Cover [Abstract] Cover [Abstract] Changes in: Changes in [Abstract] Derivatives Derivative instruments Derivative [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Other assets, net Other assets Other Assets Segment Reporting [Abstract] Segment Reporting [Abstract] Other investments Other than Securities Investment [Member] Incurred claims and claims expense related to: Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims [Abstract] Investments [Domain] Investments [Domain] Corporate Segment Corporate Segment [Member] Forecast Forecast [Member] Discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Remeasurement of projected benefit obligation Defined Benefit Plan, Amortization of Gain (Loss) Total liabilities and equity Liabilities and Equity Current year Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year Long-term Debt, Type [Axis] Long-Term Debt, Type [Axis] Investment assets, useful life (in years) Investment Assets, Useful Life Investment Assets, Useful Life Cash Cash Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Table] Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Table] Derivatives not designated as accounting hedging instruments Not Designated as Hedging Instrument [Member] EMA limited partnerships EMA Equity Method Investments [Member] Gross realized gains Debt Securities, Available-for-Sale, Realized Gain Earnings per common share applicable to common shareholders - Diluted (in dollars per share) Earnings Per Share, Diluted Reduction of allowance related to sales Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Sold Gains and losses from valuation, settlements, and hedge ineffectiveness, fair value hedges and derivatives not designated as hedges Schedule of Derivative Instruments Gain (Loss) in Statement of Financial Performance Valuation Settlements Hedge Ineffectiveness Fair Value Hedges and Not Designated Hedges [Table Text Block] Schedule of gains and losses from valuation, settlements, and hedge ineffectiveness reported on derivatives used in fair value hedging relationships and derivatives not designated as accounting hedging instruments in the statement of operations. Finance and insurance products Finance And Insurance Products [Member] Finance And Insurance Products [Member] Consolidation Items [Axis] Consolidation Items [Axis] Fixed income securities Available for sale Fixed Income Securities, Unrealized Gain Included in Other Comprehensive Income Represents the unrealized gains included in accumulated other comprehensive income as of the balance sheet date, for the fixed income securities which are categorized neither as held-to-maturity nor trading securities. Reserve for Property and Liability Insurance Claims and Claims Expense Reserve for Property Liability Insurance Claims and Claims Expense Disclosure [Text Block] Describes the various components of the reserve for property-liability future policy benefits and guaranteed minimum benefits, and for claims and claims adjustment expenses; the significant assumptions for estimating claims losses; causes of significant variances from prior periods (such as catastrophes, asbestos and environmental claims reserve losses); and reconciliations of beginning to ending reserve balances. Schedule of Available-for-sale Securities [Table] Schedule of Available-for-Sale Securities [Table] Equity securities Equity Securities [Member] Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward] Other than Temporary Impairment, Credit Losses Recognized in Earnings [Roll Forward] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Corporate Corporate Debt Securities [Member] Investment expense Investment Income, Investment Expense Cumulative effect of change in accounting principle Cumulative Effect, Period of Adoption, Adjustment [Member] Liability derivatives, gross asset Offsets-Counter-party netting Derivative Liability, Subject to Master Netting Arrangement, Asset Offset Unrealized net holding gains and losses arising during the period, net of related offsets Other Comprehensive Income (Loss), before Reclassifications, before Tax Income (loss) from discontinued operations, net of tax Income (loss) from discontinued operations, net of tax Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Stock options (in shares) Incremental Common Shares Attributable to Employee Stock Options Aggregate awards of share options to be issued to an employee under a share-based compensation arrangement considered for purposes of computing diluted earnings per share. Gross amount Derivative Asset, Subject to Master Netting Arrangement, before Offset Income taxes Increase (Decrease) in Income Taxes Payable, Net of Income Taxes Receivable Entity Address, Address Line One Entity Address, Address Line One Other comprehensive income (loss) Other Comprehensive Income (Loss), Tax Total costs and expenses Benefits, Losses and Expenses Investment collections Proceeds from Collection of Investments [Abstract] Insurance Product Line [Axis] Product and Service [Axis] Class of Stock [Domain] Class of Stock [Domain] Expected return on plan assets Defined Benefit Plan, Expected Return (Loss) on Plan Assets 2019 Origination, Three Prior Fiscal Years [Member] Origination, Three Prior Fiscal Years Interest expense Interest Expense Fair value Credit Risk Derivatives, at Fair Value, Net Retirement Plan Type [Axis] Retirement Plan Type [Axis] Contingent consideration term Disposal Group, Including Discontinued Operation, Contingent Consideration, Term Disposal Group, Including Discontinued Operation, Contingent Consideration, Term Counterparty and cash collateral netting Derivative Asset Net of Offsets and Securities Collateral Represents the amount of derivative assets, net of offsets under the master netting arrangements and net of securities collateral. Unearned premiums Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Unearned Premiums Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Unearned Premiums Schedule of gross and net amount for the Company's OTC derivatives subject to enforceable master netting arrangements Offsetting Assets and Liabilities [Table Text Block] Tabular disclosure of derivative and other financial assets and liabilities that are subject to offsetting, including master netting arrangements. Derivative instruments Fair Value of Derivative Instruments with Unrealized Net Capital Gain (Loss) Fair value as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, for which an unrealized net gain or loss is included in accumulated other comprehensive income. Premium installment receivables, net Increase (Decrease) in Premiums Receivable 2017 and prior Origination, Five Prior Fiscal Years And Prior [Member] Origination, Five Prior Fiscal Years And Prior Equity securities Payments to Acquire Equity Securities, FV-NI Underlying Asset Class [Domain] Underlying Asset Class [Domain] Accrued investment income Accrued Investment Income Receivable Schedule of changes in the restructuring liability Schedule of Restructuring Reserve by Type of Cost [Table Text Block] Weighted average dilutive potential common shares excluded due to net loss applicable to common shareholders (in shares) Weighted Average Number of Shares Outstanding, Diluted, Adjustment Credit Derivatives Contract Type [Axis] Credit Derivatives Contract Type [Axis] Allowance for credit loss Allowance for Credit Loss [Table Text Block] Allowance for Credit Loss [Table Text Block] Measurement Frequency [Axis] Measurement Frequency [Axis] Unrealized losses Available for sale Securities, Unrealized Losses for Fixed Income Securities Held for Twelve Months or Longer Period This item represents the excess of [amortized] cost over fair value of fixed income securities that have been in a loss position for twelve months or longer, and have unrealized loss position greater than 20% of cost or amortized cost for those securities which are categorized neither as held-to-maturity nor trading securities as of the balance sheet date. General General [Text Block] The disclosure of both the organization, consolidation and presentation of financial statements and the disclosure of the new accounting pronouncements adopted and not yet adopted. Net Gains (Losses) On Investments And Derivatives Net Gains (Losses) On Investments And Derivatives [Member] Net Gains (Losses) On Investments And Derivatives Beginning balance Ending balance Reinsurance Recoverable, Allowance for Credit Loss Derivative instruments Derivative Instruments, Unrealized Gain (Loss) Included in Other Comprehensive Income The amount of unrealized gains (losses) included in accumulated other comprehensive income on derivative instruments, as a result of fair value exceeding (under) its amortized cost, as of the balance sheet date. Bank loans, net Bank Loans [Member] Bank Loans [Member] Long-term Debt, Type [Domain] Long-Term Debt, Type [Domain] Retirement Benefits [Abstract] Retirement Benefits [Abstract] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Balance at beginning of period Balance at end of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value Fixed income securities Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-Sale Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Allstate Protection Allstate Protection [Member] Allstate Protection comprises two brands, the Allstate brand and Encompass brand. Reserve for future policy benefits Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Liability For Future Policy Benefits Business Combination, Recognized Identifiable Assets Acquired And Liabilities Assumed, Liability For Future Policy Benefits Credit Derivatives Credit Derivatives [Line Items] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Current Origination, Current [Member] Origination, Current Net change in short-term investments Net Change in Short Term Investments of Proceeds Managed Collateral The net change in short-term investments from the proceeds managed related to collateral received in conjunction with the entity's securities lending and over-the-counter derivatives. Net gains (losses) on investments and derivatives Disposal Group, Including Discontinued Operation, Realized Capital Gains And Losses Disposal Group, Including Discontinued Operation, Realized Capital Gains And Losses Notional amount Notional Amount of Counterparty Credit Exposure The notional amount of derivative contracts for which the entity has counterparty credit exposure. Less: Net loss attributable to noncontrolling interest Income (Loss) from Continuing Operations, Net of Tax, Attributable to Noncontrolling Interest