Reinsurance (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Property and Casualty Group	Dec. 31, 2012 Property and Casualty Group	Dec. 31, 2011 Property and Casualty Group	Dec. 31, 2013 Property and Casualty Group Minimum	Dec. 31, 2013 Property and Casualty Group Maximum	Dec. 31, 2013 Property and Casualty Group First property catastrophe reinsurance treaty	Dec. 31, 2013 Property and Casualty Group Second property catastrophe reinsurance treaty	Dec. 31, 2013 Property and Casualty Group Third property catastrophe reinsurance treaty	Dec. 31, 2014 Property and Casualty Group Effective for the next fiscal year First property catastrophe reinsurance treaty	Dec. 31, 2014 Property and Casualty Group Effective for the next fiscal year Second property catastrophe reinsurance treaty	Dec. 31, 2014 Property and Casualty Group Effective for the next fiscal year Third property catastrophe reinsurance treaty	Dec. 31, 2014 Property and Casualty Group Effective for the next fiscal year Fourth property catastrophe reinsurance treaty	Dec. 31, 2013 Property and Casualty Group Exchange	Dec. 31, 2013 Property and Casualty Group Erie Insurance Company (EIC)	Dec. 31, 2013 Property and Casualty Group Erie Insurance Company of New York (ENY)
Reinsurance
Reinsurance pooling agreement, participation (as a percent)																94.50%	5.00%	0.50%
Reinsurance pooling agreement, termination notice period (in days)							365 days
Reinsurance pooling agreement, intercompany cash settlement period (in days)								30 days
Percentage of loss coverage amount in excess of the Property & Casualty Group's loss retention per occurrence (as a percent)									90.00%	70.00%	70.00%	30.00%	90.00%	85.00%	100.00%
Loss coverage amount in excess of the Property & Casualty Group's loss retention per occurrence									$ 550	$ 225	$ 25	$ 100	$ 500	$ 200	$ 25
Property & Casualty Group's retention amount per occurrence									350	900	1,125	300	400	900	1,100
Insurance losses and loss expenses	$ 3,467	$ 3,480	$ 3,444	$ 3,360	$ 3,379	$ 3,344			$ 0	$ 0	$ 0