Indemnity Supplemental Information (Details) (USD $) In Millions, unless otherwise specified												6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2014 Indemnity	Dec. 31, 2013 Indemnity	Jun. 30, 2013 Indemnity	Dec. 31, 2012 Indemnity	Jun. 30, 2014 Exchange	Dec. 31, 2013 Exchange	Dec. 31, 2012 Exchange	Jun. 30, 2014 Erie Family Life Insurance Company (EFL)	Jun. 30, 2013 Erie Family Life Insurance Company (EFL)	Dec. 31, 2013 Erie Family Life Insurance Company (EFL)	Jun. 30, 2014 Reclassifications and eliminations	Dec. 31, 2013 Reclassifications and eliminations
Available-for-sale securities, at fair value:
Fixed maturities	$ 9,198	$ 8,688			$ 497	$ 526			$ 8,701	$ 8,162
Equity securities	940	869			26	50			914	819
Trading securities, at fair value	3,377	3,202							3,377	3,202
Limited partnerships	1,072	1,086			141	146			931	940
Other invested assets	21	21			1	1			20	20
Total investments	14,608	13,866			665	723			13,943	13,143
Cash and cash equivalents	300	452	365	400	63	49	39	12	237	403
Premiums receivable from policyholders	1,287	1,167							1,287	1,167
Reinsurance recoverable	168	172							168	172
Deferred income tax asset	1	2			1	2			0	0
Deferred acquisition costs	579	566							579	566
Other assets	517	451			112	114			405	337
Receivables from the Exchange and other affiliates					339	300									(339)	(300)
Note receivable from EFL					25	25						25			(25)	(25)
Total assets	17,460	16,676			1,205	1,213			16,619	15,788					(364)	(325)
Liabilities
Losses and loss expense reserves	3,964	3,747							3,964	3,747
Life policy and deposit contract reserves	1,789	1,758							1,789	1,758
Unearned premiums	2,788	2,598							2,788	2,598
Deferred income tax liability	557	450			0	0			557	450
Other liabilities, adjusted for consolidation presentation	541	573			450	479			455	419					(364)	(325)
Total liabilities	9,639	9,126			450	479			9,553	8,972					(364)	(325)
Shareholders' equity and noncontrolling interest
Total Indemnity shareholders' equity	755	734			755	734
Noncontrolling interest in consolidated entity - Exchange	7,066	6,816							7,066	6,816
Total equity	7,821	7,550		6,791	755	734		642	7,066	6,816	6,149
Total liabilities, shareholders' equity, and noncontrolling interest	17,460	16,676			1,205	1,213			16,619	15,788					(364)	(325)
Receivables from the Exchange and EFL									335	296		4		4
Note receivable from EFL, annual interest rate (as a percent)												6.70%
Note receivable from EFL, interest income recognized by Indemnity												$ 0.8	$ 0.8