Document and Entity Information	9 Months Ended
	Sep. 30, 2012	Oct. 17, 2012 Class A Common Stock	Oct. 17, 2012 Class B Common Stock
Entity Registrant Name	ERIE INDEMNITY CO
Entity Central Index Key	0000922621
Document Type	10-Q
Document Period End Date	Sep. 30, 2012
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		47,071,095	2,544
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q3