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Claim and Claim Adjustment Expense Reserves and Future Policy Benefit Reserves (Commercial - Net Prior Year Claim and Allocated Claim Adjustment Expense Reserve Development) (Details) - Commercial - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
Liability for Claims and Claims Adjustment Expense [Line Items] |  |  |
Commercial | $ 49 | $ 53 | $ 33
General Liability | 67 | 15 | 15
Workers' Compensation | (152) | (82) | (96)
Property and Other | (7) | 8 | 41
Total pretax (favorable) unfavorable development | $ (43) | $ (6) | $ (7)

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- Definition Net prior year claim and allocated claim adjustment expense reserve development, Commercial Auto + References No definition available. + Details
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Balance Type: | debit
Period Type: | duration

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- Definition Net prior year claim and allocated claim adjustment expense reserve development, General Liability + References No definition available. + Details
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- Definition Net prior year claim and allocated claim adjustment expense reserve development, Property and Other + References No definition available. + Details
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- Definition Net prior year claim and allocated claim adjustment expense reserve development, Workers' Compensation + References No definition available. + Details
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Balance Type: | debit
Period Type: | duration

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- Definition Pretax (favorable) unfavorable net prior year claim and allocated claim adjustment expense reserve development, excluding Life & Group + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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Period Type: |