Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Postretirement Benefits
Funding target (as a percentage of the funding target liability)	100.00%		100.00%
Defined benefit plan, plan assets, contributions by employer	$ 25,000
Cost of pension plans:
Service cost for benefits earned	12,560	$ 13,260	$ 37,681	$ 39,780
Interest cost on benefits obligation	9,941	9,206	29,823	27,618
Expected return on plan assets	(13,639)	(12,569)	(40,917)	(37,706)
Prior service cost amortization	361	357	1,082	1,071
Net actuarial loss amortization	1,830	4,027	5,490	12,080
Pension plan cost	$ 11,053	$ 14,281	$ 33,159	$ 42,843
Erie Insurance Exchange
Postretirement Benefits
Postretirement annual benefit expense reimbursed to Indemnity from the Exchange and its subsidiaries (as a percent)			57.00%