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Fair Value - Additional Information (Detail)	Sep. 30, 2025	Dec. 31, 2024	Sep. 30, 2024
Fair Value, Inputs, Level 1
Fair Value Measurements [Line Items]
Vendor quoted prices, percent of FV hierarchy level	93.00%	93.00%
Fair Value, Inputs, Level 2
Fair Value Measurements [Line Items]
Vendor quoted prices, percent of FV hierarchy level	99.00%	100.00%	100.00%

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- Definition

Fair Value Measurements [Line Items]

+ References

No definition available.

+ Details

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- 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

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Namespace Prefix:	pgr_
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- Details

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- Details

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