Business Segments (Details 2) (USD $) In Millions	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Segment Reporting Information
Life and annuity premiums and contract charges	$ 547	$ 545	$ 1,116	$ 1,089
Net investment income	1,020	1,049	2,002	2,099
Restructuring and related charges	11	13	20	24
Net (loss) income	(620)	145	(101)	265
Property-Liability
Segment Reporting Information
Total underwriting (loss) income	(1,502)	207	(1,175)	278
Net investment income	310	310	594	614
Income tax benefit (expense) on operations	460	(149)	279	(237)
Realized capital gains and losses, after-tax	(6)	(69)	32	(192)
Net (loss) income	(738)	299	(270)	463
Allstate Protection
Segment Reporting Information
Total underwriting (loss) income	(1,498)	209	(1,165)	284
Discontinued Lines and Coverages
Segment Reporting Information
Total underwriting (loss) income	(4)	(2)	(10)	(6)
Allstate Financial
Segment Reporting Information
Life and annuity premiums and contract charges	547	545	1,116	1,089
Net investment income	694	723	1,378	1,454
Periodic settlements and accruals on Nonhedge derivative financial instruments	19	11	36	28
Contract benefits and interest credited to contractholder funds	(834)	(935)	(1,713)	(1,840)
Operating costs and expenses and amortization of deferred policy acquisition costs	(213)	(157)	(435)	(335)
Restructuring and related charges		1	2	1
Income tax benefit (expense) on operations	(72)	(63)	(127)	(133)
Operating income	141	125	257	264
Realized capital gains and losses, after-tax	40	(230)	65	(335)
Valuation changes on embedded derivatives that are not hedged, after-tax	(3)		5
DAC and DSI (amortization) accretion relating to realized capital gains and losses and valuation changes on embedded derivatives that are not hedged, after-tax	(5)	4	(31)	2
DAC and DSI unlocking relating to realized capital gains and losses, After-tax			1	(18)
Reclassification of periodic settlements and accruals on non-hedge financial instruments, after-tax	(11)	(7)	(23)	(18)
Gain (loss) on disposition of operations, after-tax	4	1	(11)	2
Net (loss) income	166	(107)	263	(103)
Corporate and Other
Segment Reporting Information
Service fees	2	3	4	6
Net investment income	16	16	30	31
Operating costs and expenses	(100)	(104)	(193)	(204)
Income tax benefit (expense) on operations	32	33	63	65
Operating income	(50)	(52)	(96)	(102)
Realized capital gains and losses, after-tax	2	5	2	7
Net (loss) income	$ (48)	$ (47)	$ (94)	$ (95)

Contract benefits and interest credited to contract holder funds.

Name:	all_ContractBenefitsAndInterestCreditedToPolicyholderAccountBalances
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of deferred policy acquisition costs and sales inducement costs (amortization) accretion related to realized capital gains and losses and valuation changes on embedded derivatives that are not hedged, net of tax effect.

+ Details

Name:	all_DeferredPolicyAcquisitionAndSalesInducementsCostsAmortizationAccretionRelatedToRealizedCapitalGainsLossesAndValuationChangesOnEmbeddedDerivativesNotHedgedAfterTax
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of deferred policy acquisition costs and sales inducement costs unlocking related to realized capital gains and losses, net of tax effect.

+ Details

Name:	all_DeferredPolicyAcquisitionAndSalesInducementsCostsUnlockingRelatedToRealizedCapitalGainsLossesAfterTax
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of operating costs and expenses and amortization of deferred policy acquisition costs.

+ Details

Name:	all_DeferredPolicyAcquisitionCostAmortizationExpenseAndOtherCostAndExpensesOperating
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The gain (loss) resulting from the sale of a disposal group that is not a discontinued operation, net of tax effect.

+ Details

Name:	all_DisposalGroupNotDiscontinuedOperationGainLossOnDisposalAfterTax
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The income tax expense (benefit) pertaining to operating income or loss as measured by the entity for segment reporting purposes.

+ Details

Name:	all_IncomeTaxExpenseBenefitOnOperations
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Premiums recognized as revenue in the period on all life insurance and reinsurance contracts, as well as accident and health insurance and reinsurance contracts, after subtracting any amounts ceded to another insurer. Also includes an amount that an insurer adds to a policy's premium, or deducts from a policy's cash value or contract holder's account, as compensation for services rendered (may include fees), after subtracting any amounts ceded to another insurer.

+ Details

Name:	all_LifeAndAnnuityPremiumsAndContractChargesNetOfReinsuranceCeded
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The operating income (loss), net of tax effect, as measured by the entity for segment reporting purposes.

+ Details

Name:	all_OperatingIncomeLossAfterTax
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the periodic settlements and accruals on non-hedge derivative financial instruments.

+ Details

Name:	all_PeriodicSettlementsAndAccrualsOnNonHedgeDerivativeFinancialInstruments
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The net realized gains or losses on investments during the period after tax effect.

+ Details

Name:	all_RealizedInvestmentGainsLossesAfterTax
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of reclassification of periodic settlements and accruals on non-hedge derivative financial instruments.

+ Details

Name:	all_ReclassificationOfPeriodicSettlementsAndAccrualsOnNonHedgeDerivativeFinancialInstruments
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The operating cost and expenses as measured by the entity for segment reporting purposes.

+ Details

Name:	all_SegmentOperatingCostsAndExpenses
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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.

+ Details

Name:	all_UnderwritingGainLoss
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of valuation changes on embedded derivatives that are not hedged, net of tax effect.

+ Details

Name:	all_ValuationChangesOnEmbeddedDerivativesNotHedgedAfterTax
Namespace Prefix:	all
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total fees and commissions earned from providing services such as leasing of space or maintaining: (1) depositor accounts; (2) transfer agent; (3) fiduciary and trust; (4) brokerage and underwriting; (5) mortgage; (6) credit cards; (7) correspondent clearing; and (8) other such services and activities performed for others.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher OTS
-Name Federal Regulation (FR)
-Number Title 12
-Chapter V
-Section 563c.102
-Paragraph 13
-Subsection II

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 13
-Article 9

+ Details

Name:	us-gaap_FeesAndCommissions
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The income earned from investments in securities and property, equipment and other capital assets. It includes rent from property and equipment, dividends from shares in corporations, and interest from bonds, loans, mortgages, derivatives, commercial paper, bank accounts, certificates of deposits, treasuries, and other financial securities. It does not include realized gains and losses on investments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 16
-Article 12

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 2
-Article 7

+ Details

Name:	us-gaap_NetInvestmentIncome
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph A1, A4, A5

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 5
-Subparagraph b

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 29

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph a

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 51
-Paragraph 38
-Subparagraph c(1)

+ Details

Name:	us-gaap_ProfitLoss
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount charged against earnings in the period for incurred and estimated costs, excluding asset retirement obligations, associated with exit from or disposal of business activities or restructurings pursuant to a program that is planned and controlled by management, and materially changes either the scope of a business undertaken by an entity, or the manner in which that business is conducted.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 5
-Section P
-Subsection 3, 4

+ Details

Name:	us-gaap_RestructuringCharges
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ Details

Name:	us-gaap_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration