Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Revenues
Premiums earned/life policy revenue	$ 1,288	$ 1,175
Net investment income	109	103
Net realized investment gains	56	249
Net impairment losses recognized in earnings	0	0
Equity in earnings of limited partnerships	50	36
Service agreement and other revenue	8	8
Total revenues	1,511	1,571
Benefits and expenses
Insurance losses and loss expenses	1,034	842
Policy acquisition and underwriting expenses	321	293
Total benefits and expenses	1,355	1,135
Income (loss) from operations before income taxes and noncontrolling interest	156	436
Provision for income taxes	47	146
Net income (loss)	109	290	1,048
Indemnity
Revenues
Net investment income	4	4
Net realized investment gains	1	0
Equity in earnings of limited partnerships	6	3
Benefits and expenses
Income (loss) from operations before income taxes and noncontrolling interest	69	56
Provision for income taxes	23	19
Net income (loss)	46		163
Exchange
Revenues
Net investment income	105	99
Net realized investment gains	55	249
Equity in earnings of limited partnerships	44	33
Benefits and expenses
Net income (loss)	63		885
Management operations | Indemnity
Segment information
Indemnity's maximum management fee rate as a percent of premiums written and assumed by the Exchange (as a percent)	25.00%
Revenues
Management fee revenue	319	296
Service agreement and other revenue	7	7
Total revenues	326	303
Benefits and expenses
Cost of management operations	268	254
Income (loss) from operations before income taxes and noncontrolling interest	58	49
Investment operations | Indemnity
Revenues
Net investment income	4	4
Net realized investment gains	1	0
Net impairment losses recognized in earnings	0	0
Equity in earnings of limited partnerships	6	3
Benefits and expenses
Income (loss) from operations before income taxes and noncontrolling interest	11	7
Operating segment | Management operations
Revenues
Management fee revenue	319	296
Service agreement and other revenue	7	7
Total revenues	326	303
Benefits and expenses
Cost of management operations	268	254
Total benefits and expenses	268	254
Income (loss) from operations before income taxes and noncontrolling interest	58	49
Provision for income taxes	20	17
Net income (loss)	38	32
Operating segment | Management operations | Indemnity
Segment information
Indemnity's maximum management fee rate as a percent of premiums written and assumed by the Exchange (as a percent)	25.00%
Operating segment | Property and casualty insurance operations
Revenues
Premiums earned/life policy revenue	1,268	1,156
Total revenues	1,268	1,156
Benefits and expenses
Insurance losses and loss expenses	1,007	817
Policy acquisition and underwriting expenses	365	328
Total benefits and expenses	1,372	1,145
Income (loss) from operations before income taxes and noncontrolling interest	(104)	11
Provision for income taxes	(36)	4
Net income (loss)	(68)	7
Operating segment | Life insurance operations
Revenues
Premiums earned/life policy revenue	20	19
Service agreement and other revenue	1	1
Total revenues	21	20
Benefits and expenses
Insurance losses and loss expenses	28	26
Policy acquisition and underwriting expenses	9	9
Total benefits and expenses	37	35
Income (loss) from operations before income taxes and noncontrolling interest	(16)	(15)
Provision for income taxes	(6)	(5)
Net income (loss)	(10)	(10)
Operating segment | Life insurance operations | Erie Family Life Insurance Company (EFL)
Segment information
Total investment revenues	29	26
Benefits and expenses
Income (loss) from operations before income taxes and noncontrolling interest	13	11
Operating segment | Investment operations
Revenues
Net investment income	112	106
Net realized investment gains	56	249
Net impairment losses recognized in earnings	0	0
Equity in earnings of limited partnerships	50	36
Total revenues	218	391
Benefits and expenses
Income (loss) from operations before income taxes and noncontrolling interest	218	391
Provision for income taxes	69	130
Net income (loss)	149	261
Eliminations
Revenues
Premiums earned/life policy revenue	0	0
Net investment income	(3)	(3)
Management fee revenue	(319)	(296)
Total revenues	(322)	(299)
Benefits and expenses
Cost of management operations	(268)	(254)
Insurance losses and loss expenses	(1)	(1)
Policy acquisition and underwriting expenses	(53)	(44)
Total benefits and expenses	$ (322)	$ (299)