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Reinsurance and Indemnification - FHCF Contract (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Reinsurance Retention Policy [Line Items] |  |  |
Property-liability insurance premiums earned | $ 1,383 | $ 1,407 | $ 1,306
Florida Hurricane Catastrophe Fund |  |  |
Reinsurance Retention Policy [Line Items] |  |  |
Limit of aggregate losses under aggregate excess agreement | 295 |  |
Retention amount for catastrophe reinsurance agreement contracts | 20 |  |
Reinsurance ceded amount | 118 |  |
Property-liability insurance premiums earned | 9 | 9 | 10
Catastrophe Reinsurance Program |  |  |
Reinsurance Retention Policy [Line Items] |  |  |
Limit of aggregate losses under aggregate excess agreement | 400 |  |
Retention amount for catastrophe reinsurance agreement contracts | 500 |  |
Property-liability insurance premiums earned | $ 425 | $ 386 | $ 343

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- Definition The limit of aggregated losses per contract year beyond which coverage provided by an aggregate excess agreement applies. + References No definition available. + Details
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- Definition Represents the retention amount of catastrophe reinsurance agreement contracts. + References No definition available. + Details
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