Investments - Net investment income (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Net Investment Income:
Investment income, before expense	$ 650	$ 645
Investment expense	(75)	(51)
Net investment income	575	594
Fixed income securities
Net Investment Income:
Investment income, before expense	390	267
Equity securities
Net Investment Income:
Investment income, before expense	11	36
Mortgage loans
Net Investment Income:
Investment income, before expense	8	8
Limited partnership interests
Net Investment Income:
Investment income, before expense	134	292
Short-term investments
Net Investment Income:
Investment income, before expense	66	2
Other investments
Net Investment Income:
Investment income, before expense	$ 41	$ 40

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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