Employee Benefit Plans Assets Held in Deferral Plan Irrevocable Grantor Trust Account (Detail) - USD ($) shares in Millions, $ in Millions |
Dec. 31, 2021 |
Dec. 31, 2020 |
---|---|---|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
Assets held in Deferral Plan Irrevocable Grantor Trust account | $ 326.2 | $ 301.4 |
Other Investment Funds | ||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
Assets held in Deferral Plan Irrevocable Grantor Trust account | 189.1 | 167.2 |
Common equities | Progressive common shares | ||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | ||
Assets held in Deferral Plan Irrevocable Grantor Trust account | $ 137.1 | $ 134.2 |
Deferred Compensation Arrangement with Individual, Shares Authorized for Issuance | 2.4 | 2.8 |