Operating Results (Parenthetical) (Detail) (Personal Lines, Personal Auto, Underwriting Operations)	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Personal Lines \| Personal Auto \| Underwriting Operations
Segment Reporting Information [Line Items]
Personal auto insurance percentage of the total personal lines segment net premiums earned	91.00%	91.00%	91.00%	91.00%

Percentage of segment revenue attributable to personal auto insurance.

No definition available.

Name:	pgr_PercentageOfSegmentRevenueAttributableToPersonalAutoInsurance
Namespace Prefix:	pgr_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration