Postretirement Benefits - Pension Plan (Income) Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cost of pension plans:
Service cost for benefits earned	$ 28,763	$ 50,242	$ 53,041
Interest cost on benefit obligation	50,193	39,764	36,824
Expected return on plan assets	(68,869)	(54,557)	(50,275)
Prior service cost amortization	1,446	1,443	1,428
Net actuarial (gain) loss amortization	(15,331)	7,320	16,106
Pension plan (income) cost	$ (3,798)	$ 44,212	$ 57,124
Defined benefit plan, net periodic benefit cost (credit) excluding service cost, statement of income or comprehensive income	Other income (expense)
Erie Insurance Exchange (EIE) | Employee Pension 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 (EIE) | Supplemental Employee Retirement Plan (SERP)
Postretirement benefits
Postretirement annual benefit income and expense reimbursed to and from, respectively, the Exchange and its subsidiaries (as a percent)	36.00%