Investments - Schedule of Gross Unrealized Losses by Unrealized Loss Position and Credit Quality (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Investment grade
Investment [Line Items]
Fixed income securities with unrealized loss position less than 20% of amortized cost, net	$ (1,092)
Fixed income securities with unrealized loss position greater than or equal to 20% of amortized cost, net	(36)
Total unrealized losses	(1,128)	$ (1,234)
Below investment grade
Investment [Line Items]
Fixed income securities with unrealized loss position less than 20% of amortized cost, net	(100)
Fixed income securities with unrealized loss position greater than or equal to 20% of amortized cost, net	(2)
Total unrealized losses	(102)	(200)
Fixed income securities
Investment [Line Items]
Fixed income securities with unrealized loss position less than 20% of amortized cost, net	(1,192)
Fixed income securities with unrealized loss position greater than or equal to 20% of amortized cost, net	(38)
Total unrealized losses	$ (1,230)	$ (1,434)