Statutory Information (Details) (USD $)		12 Months Ended					12 Months Ended				12 Months Ended				12 Months Ended				12 Months Ended
	Dec. 31, 2011 Pennsylvania and New York	Dec. 31, 2011 Erie Insurance Company	Dec. 31, 2010 Erie Insurance Company	Dec. 31, 2009 Erie Insurance Company	Dec. 31, 2011 Erie Insurance Company Pennsylvania	Dec. 31, 2011 Erie Insurance Company Pennsylvania Maximum	Dec. 31, 2011 Erie Insurance Company of New York	Dec. 31, 2010 Erie Insurance Company of New York	Dec. 31, 2009 Erie Insurance Company of New York	Dec. 31, 2011 Erie Insurance Company of New York New York Maximum	Dec. 31, 2011 Erie Insurance Property and Casualty Company	Dec. 31, 2010 Erie Insurance Property and Casualty Company	Dec. 31, 2009 Erie Insurance Property and Casualty Company	Dec. 31, 2011 Erie Insurance Property and Casualty Company Pennsylvania Maximum	Dec. 31, 2011 Flagship City Insurance Company	Dec. 31, 2010 Flagship City Insurance Company	Dec. 31, 2009 Flagship City Insurance Company	Dec. 31, 2011 Flagship City Insurance Company Pennsylvania Maximum	Dec. 31, 2011 Erie Family Life Insurance Company ("EFL")	Dec. 31, 2010 Erie Family Life Insurance Company ("EFL")	Dec. 31, 2009 Erie Family Life Insurance Company ("EFL")	Dec. 31, 2011 Exchange	Dec. 31, 2010 Exchange	Dec. 31, 2009 Exchange	Dec. 31, 2011 Exchange Pennsylvania and New York Property and casualty insurance operations	Dec. 31, 2011 Exchange Pennsylvania	Dec. 31, 2012 Exchange Pennsylvania Life insurance operations Maximum	Dec. 31, 2011 Exchange Pennsylvania Life insurance operations Maximum
Statutory net income and capital and surplus determined in accordance with SAP
SAP Net income (loss)		$ 9,000,000	$ 21,000,000	$ 16,000,000			$ (1,000,000)	$ 2,000,000	$ 2,000,000		$ 0	$ 0	$ 0		$ 0	$ 0	$ 0		$ 34,000,000	$ 38,000,000	$ 3,000,000	$ 182,000,000	$ 531,000,000	$ (56,000,000)
SAP Capital and surplus		260,000,000	251,000,000				20,000,000	20,000,000			11,000,000	10,000,000			11,000,000	11,000,000			245,000,000	208,000,000		5,166,000,000	5,070,000,000		302,000,000
Minimum statutory capital and surplus requirements																									12,000,000
Cash and securities deposited by the property and casualty and life entities with regulatory authorities	14,000,000
NAIC prepared statutory surplus					256,000,000																					4,700,000,000
Dividend available for distribution without prior approval as percentage of statutory surplus						10.00%				10.00%				10.00%				10.00%										10.00%
Dividend available for distribution without prior approval as percentage of adjusted net investment income										100.00%
Maximum dividend payout that could be received																									30,000,000
Dividend payout that could be received from subsidiaries without prior approval																											$ 34,000,000