Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 31, 2019
Cover page.
Document Quarterly Report	true
Document Transition Report	false
Security Exchange Name	NYSE
Title of 12(b) Security	Common Shares, $1.00 Par Value
City Area Code	440
Entity Incorporation, State or Country Code	OH
Entity Registrant Name	PROGRESSIVE CORP/OH/
Entity Central Index Key	0000080661
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Entity File Number	001-09518
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		584,630,089
Trading Symbol	PGR
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Tax Identification Number	34-0963169
Entity Address, Address Line One	6300 Wilson Mills Road,
Entity Address, City or Town	Mayfield Village,
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	44143
Local Phone Number	461-5000
Entity Information, Former Legal or Registered Name	Not Applicable
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false