Investments - Schedule of Gross Unrealized Losses by Unrealized Loss Position and Credit Quality (Details) - USD ($)	Sep. 30, 2023	Dec. 31, 2022
Investment grade fixed income securities
Investments [Line Items]
Fixed income securities with unrealized loss position less than 20% of amortized cost, net	$ (2,444,000,000)
Fixed income securities with unrealized loss position greater than or equal to 20% of amortized cost, net	(387,000,000)
Total unrealized losses	2,831,000,000	$ 2,418,000,000
Below investment grade fixed income securities
Investments [Line Items]
Fixed income securities with unrealized loss position less than 20% of amortized cost, net	(312,000,000)
Fixed income securities with unrealized loss position greater than or equal to 20% of amortized cost, net	(94,000,000)
Total unrealized losses	406,000,000	559,000,000
Unrealized losses having loss of less than twenty percent	25,000,000
Unrealized losses	94,000,000
Fixed income securities
Investments [Line Items]
Fixed income securities with unrealized loss position less than 20% of amortized cost, net	(2,756,000,000)
Fixed income securities with unrealized loss position greater than or equal to 20% of amortized cost, net	(481,000,000)
Total unrealized losses	$ 3,237,000,000	$ 2,977,000,000