XML 25 R52.htm IDEA: XBRL DOCUMENT v2.4.1.9
Indemnity Capital Stock (Details 2) (Indemnity, Class A, Stock repurchase program, USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Oct. 31, 2011
Indemnity | Class A | Stock repurchase program
    
Stock repurchases    
Amount of authorized stock repurchases approved for continuation under the current program   $ 150us-gaap_StockRepurchaseProgramAuthorizedAmount1
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareRepurchaseProgramAxis
= erie_ShareRepurchaseProgram2004Member
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
Approximate amount of repurchase authority remaining under the current stock repurchase program $ 18us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
/ dei_LegalEntityAxis
= us-gaap_ParentCompanyMember
/ us-gaap_ShareRepurchaseProgramAxis
= erie_ShareRepurchaseProgram2004Member
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember