Investments - Schedule of Net Investment Income (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Net Investment Income:
Investment income, before expense	$ 837	$ 650
Investment expense	(73)	(75)
Net investment income	764	575
Fixed income securities
Net Investment Income:
Investment income, before expense	526	390
Equity securities
Net Investment Income:
Investment income, before expense	15	11
Mortgage loans
Net Investment Income:
Investment income, before expense	9	8
Limited partnership interests
Net Investment Income:
Investment income, before expense	199	134
Short-term investments
Net Investment Income:
Investment income, before expense	67	66
Other investments
Net Investment Income:
Investment income, before expense	$ 21	$ 41

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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