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Investment Information - Net investment income (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Net investment income:
Gross investment income		$ 433	$ 422	$ 1,269	$ 1,158
Investment expenses		(25)	(23)	(78)	(68)
Net investment income		408	399	1,191	1,090
Fixed maturities
Net investment income:
Gross investment income		379	340	1,081	926
Short-term investments
Net investment income:
Gross investment income		25	38	75	102
Equity securities
Net investment income:
Gross investment income		10	9	31	27
Other
Net investment income:
Gross investment income	[1]	$ 19	$ 35	$ 82	$ 103
[1] Amounts include dividends and other distributions on investment funds, term loan investments, funds held balances, cash balances and other items.

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