Significant Accounting Policies (Details) (Erie Family Life Insurance Company ("EFL"))	Dec. 31, 2011
Erie Family Life Insurance Company ("EFL")
Significant Accounting Policies
Ownership interest in EFL residing within the consolidated entity, or "Erie Insurance Group", as a result of consolidation of the Exchange with Indemnity (as a percent)	100.00%

The percentage of ownership of an affiliated entity that resides within the consolidated entity, due to the consolidation of variable interest entities.

No definition available.

Name:	erie_AffiliateOwnershipPercentageDueToConsolidationOfVariableInterestEntity
Namespace Prefix:	erie_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant