Investments - Schedule of Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Net Investment Income:
Investment income, before expense	$ 925	$ 837
Investment expense	(71)	(73)
Net investment income	854	764
Fixed income securities
Net Investment Income:
Investment income, before expense	608	526
Equity securities
Net Investment Income:
Investment income, before expense	20	15
Mortgage loans
Net Investment Income:
Investment income, before expense	10	9
Limited partnership interests
Net Investment Income:
Investment income, before expense	194	199
Short-term investments
Net Investment Income:
Investment income, before expense	72	67
Other investments
Net Investment Income:
Investment income, before expense	$ 21	$ 21

Represents the total of interest and dividend income, including any amortization and accretion (as applicable) of discounts and premiums, earned from (1) loans and leases whether held-for-sale or held-in-portfolio; (2) investment securities; (3) federal funds sold; (4) securities purchased under agreements to resell; (5) investments in banker's acceptances, commercial paper, or certificates of deposit; (6) dividend income; or (7) other investments not otherwise specified herein.

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