Summary of Significant Accounting Policies (Details 5) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Summary of Significant Accounting Policies
Decrease in the deferred policy acquisition costs ("DAC") on adoption of new accounting guidance associated with acquiring or renewing insurance contracts	$ 571
Decrease in Shareholders' equity on adoption of new accounting guidance associated with acquiring or renewing insurance contracts	$ 375

The amount of decrease in deferred policy acquisition costs ("DAC") balance on adoption of new accounting guidance associated with acquiring or renewing insurance contracts.

No definition available.

Name:	all_DecreaseInDeferredPolicyAcquisitionCostsOnAdoptionOfNewAccountingGuidanceForAcquiringOrRenewingInsuranceContracts
Namespace Prefix:	all_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant