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Investment Information - Net investment income (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2025	Mar. 31, 2024
Net investment income:
Gross investment income		$ 407	$ 350
Investment expenses		(29)	(23)
Net investment income		378	327
Fixed maturities
Net investment income:
Gross investment income		342	280
Short-term investments
Net investment income:
Gross investment income		26	29
Equity securities
Net investment income:
Gross investment income		11	8
Other
Net investment income:
Gross investment income	[1]	$ 28	$ 33
[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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