Indemnity Supplemental Information (Details) (USD $) In Millions, unless otherwise specified												3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2014 Indemnity	Dec. 31, 2013 Indemnity	Mar. 31, 2013 Indemnity	Dec. 31, 2012 Indemnity	Mar. 31, 2014 Exchange	Dec. 31, 2013 Exchange	Dec. 31, 2012 Exchange	Mar. 31, 2014 Erie Family Life Insurance Company (EFL)	Mar. 31, 2013 Erie Family Life Insurance Company (EFL)	Dec. 31, 2013 Erie Family Life Insurance Company (EFL)	Mar. 31, 2014 Reclassifications and eliminations	Dec. 31, 2013 Reclassifications and eliminations
Available-for-sale securities, at fair value:
Fixed maturities	$ 8,881	$ 8,688			$ 502	$ 526			$ 8,379	$ 8,162
Equity securities	887	869			35	50			852	819
Trading securities, at fair value	3,253	3,202							3,253	3,202
Limited partnerships	1,098	1,086			145	146			953	940
Other invested assets	21	21			1	1			20	20
Total investments	14,140	13,866			683	723			13,457	13,143
Cash and cash equivalents	379	452	388	400	44	49	41	12	335	403
Premiums receivable from policyholders	1,194	1,167							1,194	1,167
Reinsurance recoverable	175	172							175	172
Deferred income tax asset		2			0	2				0
Deferred acquisition costs	558	566							558	566
Other assets	485	451			113	114			372	337
Receivables from the Exchange and other affiliates					301	300									(301)	(300)
Note receivable from EFL					25	25						25			(25)	(25)
Total assets	16,931	16,676			1,166	1,213			16,091	15,788					(326)	(325)
Liabilities
Losses and loss expense reserves	3,838	3,747							3,838	3,747
Life policy and deposit contract reserves	1,775	1,758							1,775	1,758
Unearned premiums	2,625	2,598							2,625	2,598
Deferred income tax liability	492.0	450.0			0.2	0			492.0	450.0
Other liabilities, adjusted for consolidation presentation	511	573			424	479			413	419					(326)	(325)
Total liabilities	9,241	9,126			424	479			9,143	8,972					(326)	(325)
Shareholders' equity and noncontrolling interest
Total Indemnity shareholders' equity	742	734			742	734
Noncontrolling interest in consolidated entity - Exchange	6,948	6,816							6,948	6,816
Total equity	7,690	7,550		6,791	742	734		642	6,948	6,816	6,149
Total liabilities, shareholders' equity, and noncontrolling interest	16,931	16,676			1,166	1,213			16,091	15,788					(326)	(325)
Receivables from the Exchange and EFL									296	296		5		4
Note receivable from EFL, annual interest rate (as a percent)												6.70%
Note receivable from EFL, interest income recognized by Indemnity												$ 0.4	$ 0.4