Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Unbilled Audit Premiums	$ 10	$ (27)	$ 4
Weighted average shares held in grantor trust	7,728,466
Indefinite-lived Intangible Assets [Line Items]
Basic weighted average number of shares outstanding (in shares)	184,953	186,924	190,722
Deposit contracts, liabilities	$ 35	$ 38
Depreciation	52	53	$ 54
Interest payments	141	155	160
Income taxes paid	244	103	$ 125
Other Assets
Indefinite-lived Intangible Assets [Line Items]
Intangible assets, net (excluding goodwill)	$ 85	$ 93

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Carrying amount of liabilities as of the balance sheet date pertaining to amounts received by the insurer or reinsurer from the insured (including a ceding company) under insurance or reinsurance contracts for which insurance risk is not transferred.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

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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.

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Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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Amount of cash paid for interest, excluding capitalized interest, classified as operating activity. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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Number of shares of restricted stock determined by relating the portion of time within a reporting period that restricted shares have been outstanding to the total time in that period. Restricted shares are subject to sales, contractual, regulatory or other restrictions that prevent or inhibit the holder from freely disposing of them before the restriction ends.

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Increase (Decrease) In Earned Unbilled Audit Premiums

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