Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Postretirement Benefits
Defined benefit plan asset	$ 65,163		$ 65,163		$ 0
Cost of pension plans:
Service cost for benefits earned	7,190	$ 12,560	21,572	$ 37,681
Interest cost on benefit obligation	12,548	9,941	37,644	29,823
Expected return on plan assets	(17,217)	(13,639)	(51,652)	(40,917)
Prior service cost amortization	362	361	1,085	1,082
Net actuarial (gain) loss amortization	(3,833)	1,830	(11,498)	5,490
Pension plan (income) cost	$ (950)	$ 11,053	$ (2,849)	$ 33,159
Defined benefit plan, net periodic benefit cost (credit) excluding service cost, statement of income or comprehensive income			Other income
Employee pension plan | Funded Plan | Qualified Plan
Postretirement Benefits
Funding target (as a percentage of the funding target liability)	100.00%		100.00%
Defined benefit plan, plan assets, contributions by employer	$ 95,000
Defined benefit plan asset	$ 65,200		$ 65,200
Erie Insurance Exchange | Employee pension plan | Funded Plan | Qualified Plan
Postretirement Benefits
Postretirement annual benefit income and expense reimbursed to and from, respectively, the Exchange and its subsidiaries (as a percent)			60.00%
Erie Insurance Exchange | Supplemental employee retirement plan (SERP) | Unfunded Plan | Nonqualified Plan
Postretirement Benefits
Postretirement annual benefit income and expense reimbursed to and from, respectively, the Exchange and its subsidiaries (as a percent)			36.00%