Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Financing Receivable, Allowance for Credit Losses, Policy for Uncollectible Amounts	We perform analyses to evaluate our premiums receivables for expected credit losses, based on historical and current collections experience using actuarial analysis, to determine estimated rates of default. These rates are applied to the stratified subsets of our consumer receivable balances, based on the age of the receivable, to establish an allowance for credit loss. Progressive’s premiums receivables are short-term in nature and, generally, premiums are collected prior to providing risk coverage, minimizing our exposure to credit risk. Premiums receivables balances are written off once we have exhausted our collection efforts.