Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 12, 2018
Entity Registrant Name	ERIE INDEMNITY CO
Entity Central Index Key	0000922621
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Class A
Entity Common Stock, Shares Outstanding		46,189,068
Class B
Entity Common Stock, Shares Outstanding		2,542