Investments - Schedule of Gross Unrealized Losses by Unrealized Loss Position and Credit Quality (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Investment grade
Investment [Line Items]
Fixed income securities with unrealized loss position less than 20% of amortized cost, net	$ (1,167)
Fixed income securities with unrealized loss position greater than or equal to 20% of amortized cost, net	(67)
Total unrealized losses	(1,234)	$ (2,418)
Below investment grade
Investment [Line Items]
Fixed income securities with unrealized loss position less than 20% of amortized cost, net	(173)
Fixed income securities with unrealized loss position greater than or equal to 20% of amortized cost, net	(27)
Total unrealized losses	(200)	(559)
Unrealized losses having loss of less than twenty percent	5
Unrealized losses having loss of greater than twenty percent	25
Fixed income securities
Investment [Line Items]
Fixed income securities with unrealized loss position less than 20% of amortized cost, net	(1,340)
Fixed income securities with unrealized loss position greater than or equal to 20% of amortized cost, net	(94)
Total unrealized losses	$ (1,434)	$ (2,977)