XML 106 R84.htm IDEA: XBRL DOCUMENT v3.22.0.1
Concentrations of Credit Risk (Details) - USD ($)
$ in Millions
Dec. 31, 2021
Dec. 31, 2020
Jan. 01, 2020
Concentration Risk [Line Items]      
Receivables from Erie Insurance Exchange and its affiliates $ 479.1 $ 494.6  
Receivables from Erie Insurance Exchange, allowance for credit loss $ 0.5 $ 0.6  
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 | Erie Insurance Exchange (EIE)      
Concentration Risk [Line Items]      
Receivables from Erie Insurance Exchange, allowance for credit loss     $ 0.6