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Investments (Narrative) (Details) $ in Millions	3 Months Ended	9 Months Ended
Investments (Narrative) (Details) $ in Millions	Sep. 30, 2024 USD ($) securities	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) securities
Investment Narrative [Line Items]
Securities As Percentage Of Consolidated Stockholder Equity	10.00%
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	100.00%		100.00%
Funds withheld at interest	$ 5,545		$ 5,683
Funds Held Under Reinsurance Agreements Asset Specific Client	$ 3,100
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions \| securities	5,308,000		5,788
Financing Receivable, before Allowance for Credit Loss	$ 8,493		$ 7,459
Real Estate Owned, Transfer to Real Estate Owned	23	$ 36
Accounts Receivable, Noncurrent, Nonaccrual	23	41
Real Estate Held For Sale Transferred To Held For Use	21
Impaired Financing Receivable Recorded Investment Before Allowance	$ 90	$ 68
CALIFORNIA
Investment Narrative [Line Items]
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	12.40%
TEXAS
Investment Narrative [Line Items]
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	9.70%
CANADA
Investment Narrative [Line Items]
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	7.60%
UNITED KINGDOM
Investment Narrative [Line Items]
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	2.60%
WASHINGTON
Investment Narrative [Line Items]
Mortgage Loans On Real Estate Commercial And Consumer Net Percentage Of Total	6.30%