Segment Information Operating Results (Parenthetical) (Detail) (Underwriting Operations, Personal Lines, Personal Auto)	3 Months Ended	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Underwriting Operations \| Personal Lines \| Personal Auto
Segment Reporting Information [Line Items]
Personal auto insurance percentage of the total personal lines segment net premiums earned	92.00%	91.00%	92.00%	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