XML 56 R45.htm IDEA: XBRL DOCUMENT
v3.23.3

Fair Value - Additional Information (Detail) | Sep. 30, 2023 USD ($) security | Dec. 31, 2022 USD ($) | Sep. 30, 2022 USD ($)
--- | --- | --- | ---
Fair Value Measurements [Line Items] |  |  |
Investments, fair value | $ 61,870,500,000 | $ 53,548,300,000 | $ 52,330,400,000
Fair Value, Inputs, Level 1 |  |  |
Fair Value Measurements [Line Items] |  |  |
Vendor quoted prices, percent of FV hierarchy level | 93.00% |  | 90.00%
Investments, fair value | $ 38,630,600,000 | $ 30,799,700,000 | $ 29,292,200,000
Fair Value, Inputs, Level 2 |  |  |
Fair Value Measurements [Line Items] |  |  |
Vendor quoted prices, percent of FV hierarchy level | 99.00% | 98.00% | 98.00%
Dealer quoted prices, percent of FV hierarchy level | 1.00% | 2.00% | 2.00%
Investments, fair value | $ 23,135,300,000 | $ 22,626,700,000 | $ 22,937,600,000
Fair Value, Inputs, Level 3 |  |  |
Fair Value Measurements [Line Items] |  |  |
Investments, fair value | $ 104,600,000 | 121,900,000 | 100,600,000
Fair Value, Inputs, Level 3 | Nonredeemable preferred stocks |  |  |
Fair Value Measurements [Line Items] |  |  |
Security type reclassification, level 3 securities | security | 1 |  |
Available-for-sale Securities |  |  |
Fair Value Measurements [Line Items] |  |  |
Investments, fair value | $ 58,387,100,000 | 49,513,600,000 | 48,410,700,000
Available-for-sale Securities | Total fixed maturities |  |  |
Fair Value Measurements [Line Items] |  |  |
Investments, fair value | 56,591,900,000 | 46,651,900,000 | 44,173,100,000
Available-for-sale Securities | Fair Value, Inputs, Level 1 |  |  |
Fair Value Measurements [Line Items] |  |  |
Investments, fair value | 36,057,000,000 | 27,977,300,000 | 26,634,000,000
Available-for-sale Securities | Fair Value, Inputs, Level 1 | Total fixed maturities |  |  |
Fair Value Measurements [Line Items] |  |  |
Investments, fair value | 34,293,800,000 | 25,176,600,000 | 22,414,400,000
Available-for-sale Securities | Fair Value, Inputs, Level 2 |  |  |
Fair Value Measurements [Line Items] |  |  |
Investments, fair value | 22,330,100,000 | 21,536,300,000 | 21,776,700,000
Available-for-sale Securities | Fair Value, Inputs, Level 2 | Total fixed maturities |  |  |
Fair Value Measurements [Line Items] |  |  |
Investments, fair value | 22,298,100,000 | 21,475,300,000 | 21,758,700,000
Available-for-sale Securities | Fair Value, Inputs, Level 3 |  |  |
Fair Value Measurements [Line Items] |  |  |
Investments, fair value | 0 | 0 | 0
Available-for-sale Securities | Fair Value, Inputs, Level 3 | Total fixed maturities |  |  |
Fair Value Measurements [Line Items] |  |  |
Investments, fair value | $ 0 | $ 0 | $ 0

X
- Definition The percentage of securities with prices quoted by dealers, calculated based on the total Fair Value in the hierarchy level (Level 1, Level 2, or Level 3). + References No definition available. + Details
Name: | pgr_DealerQuotedPricesPercentofFVHierarchyLevel
Namespace Prefix: | pgr_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Reclassification of existing position between security types due to conversion option or other corporate action. Value represents number of positions reclassified during the period. + References No definition available. + Details
Name: | pgr_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPreferredStockConversionNumberOfSecurities
Namespace Prefix: | pgr_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair Value Measurements [Line Items] + References No definition available. + Details
Name: | pgr_FairValueMeasurementsLineItems
Namespace Prefix: | pgr_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage of securities with prices quoted by vendors, calculated based on the total Fair Value in the hierarchy level (Level 1, Level 2, or Level 3). + References No definition available. + Details
Name: | pgr_VendorQuotedPricesPercentofFVHierarchyLevel
Namespace Prefix: | pgr_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 820 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482106/820-10-50-2 + Details
Name: | us-gaap_InvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | pgr_InvestmentPortfolioAxis=us-gaap_NonredeemablePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_AvailableforsaleSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InformationByCategoryOfDebtSecurityAxis=us-gaap_FixedMaturitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |