Investments - Narrative (Details)	12 Months Ended
Dec. 31, 2024 USD ($) loan	Dec. 31, 2023 USD ($) loan	Dec. 31, 2022 USD ($)
Debt Securities, Available-for-sale [Line Items]
Non-income producing investment fair value	$ 32,000,000	$ 47,000,000
Accrued interest receivable	476,000,000	450,000,000
FHLB collateral pledged	4,289,000,000	4,345,000,000
Available for sale securities, allowance for credit losses	67,000,000	$ 42,000,000
Available-for-sale, securities in unrealized loss position, allowance for credit loss	$ 0
Commercial mortgage loans, percentage of investments	4.00%	4.00%
DSC ratio, amortization period	25 years
Mortgage loans past due 90 days	$ 94,000,000	$ 57,000,000
Purchased mortgage loans with credit deterioration	0	0
Gross investment income	3,423,000,000	2,864,000,000	$ 2,088,000,000
Reinsurance agreement, recognized gains (losses)	$ (30,000,000)	(123,000,000)	381,000,000
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Prepaid expenses and other assets
Funds Withheld for Reinsurance
Debt Securities, Available-for-sale [Line Items]
Gross investment income	$ 636,000,000	$ 339,000,000	$ 109,000,000
90 days or more past due
Debt Securities, Available-for-sale [Line Items]
Mortgage loans in process of foreclosure	$ 81,000,000
United States
Debt Securities, Available-for-sale [Line Items]
Residential mortgage loans, location percentage	100.00%
Residential mortgage
Debt Securities, Available-for-sale [Line Items]
Percentage of total investments	5.00%	5.00%
Loan charge offs	$ 0
Mortgage loans past due 90 days	85,000,000	$ 57,000,000
Interest receivable	$ 28,000,000	$ 24,000,000
Commercial mortgage
Debt Securities, Available-for-sale [Line Items]
Number of loans delinquent in principal or interest payments \| loan	1	0
Mortgage loans past due 90 days	$ 9,000,000	$ 0
Interest receivable	$ 8,000,000	7,000,000
Mortgage loans \| 90 days or more past due
Debt Securities, Available-for-sale [Line Items]
Mortgage loans in process of foreclosure		41,000,000
Mortgage loans \| Residential mortgage
Debt Securities, Available-for-sale [Line Items]
Allowance for expected credit loss, probability of loss/default model, projected loss, forecast period	2 years
Allowance for credit loss, probability of loss/default, using market historical loss experience, period	3 years
Mortgage loans \| Commercial mortgage
Debt Securities, Available-for-sale [Line Items]
Allowance for expected credit loss, probability of loss/default model, projected loss, forecast period	2 years
Allowance for credit loss, probability of loss/default, using market historical loss experience, period	3 years
Fixed maturity securities, available-for-sale
Debt Securities, Available-for-sale [Line Items]
Assets held by insurance regulators	$ 997,000,000	$ 141,000,000

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Carrying amount of cash and investment securities on deposit with state regulatory authorities in connection with capital requirements.

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Amount excluding accrued interest, of allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

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Amount, before investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

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