Reinsurance - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024	Dec. 31, 2024
Ceded Credit Risk [Line Items]
Investments	$ 123,404.0		$ 123,388.0
Other investments	6,345.0		6,272.0
Deposit assets, net of allowance for credit losses	30,752.0		30,537.0
LPINE
Ceded Credit Risk [Line Items]
Deposits assets	7,900.0		7,900.0
Investments	11,500.0		11,500.0
LPINE \| Fixed Annuities
Ceded Credit Risk [Line Items]
Reinsurance recoverables	3,500.0		3,700.0
Reinsurance recoverables on unpaid losses	9.0		14.0
LNBAR
Ceded Credit Risk [Line Items]
Reinsurance recoverables	14,000.0		14,200.0
Reinsurance recoverables on unpaid losses	4,000.0		4,100.0
Reinsurance recoverable for unpaid claims, amortization	45.0	$ 43.0
Other investments	1,500.0		1,400.0
Trust funded to support reinsurance receivable	12,200.0		12,200.0
Fortitude Re \| Fixed Annuities
Ceded Credit Risk [Line Items]
Reinsurance recoverables	10,600.0		10,600.0
Reinsurance recoverables on unpaid losses	2,600.0		2,600.0
Reinsurance recoverable for unpaid claims, amortization	23.0	$ 22.0
Deposit assets, net of allowance for credit losses	$ 2,800.0		$ 3,000.0

Reinsurance Recoverables On Unpaid Losses, Amortization

No definition available.

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- Definition

Funds held in trust by the reinsurer to support the sale of the Entity's reinsurance business through an indemnity reinsurance agreement.

+ References

No definition available.

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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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The carrying amount of the asset transferred to a third party to serve as a deposit, which typically serves as security against failure by the transferor to perform under terms of an agreement.

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Sum of the carrying amounts as of the balance sheet date of all investments.

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- Definition

Amount before valuation allowance recoverable under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, premium paid, policy benefits and policy reserves.

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Amount before valuation allowance of reinsurance recoverables for losses reported to the ceding insurer but not yet paid, and for amounts expected based upon statistical projections and other measures of incurred losses and loss settlement expenses which have not yet been reported to the ceding insurer.

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