Investment Information - Other investments (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Option, Quantitative Disclosures [Line Items]
Other investments	$ 2,488	$ 1,644
Other investments
Fair Value, Option, Quantitative Disclosures [Line Items]
Other investments	1,777	1,043
Fixed maturities
Fair Value, Option, Quantitative Disclosures [Line Items]
Other investments	683	554
Equity securities
Fair Value, Option, Quantitative Disclosures [Line Items]
Other investments	7	14
Short-term investments
Fair Value, Option, Quantitative Disclosures [Line Items]
Other investments	$ 21	$ 33