Investments - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Investment [Line Items]
Mortgage loans, net	$ 822,000,000	$ 762,000,000
Fixed income securities	48,865,000,000	42,485,000,000
Short-term investments	$ 5,144,000,000	4,173,000,000
Percentage of credit concentration risk of single issuer and affiliates of shareholder's equity	10.00%
Fixed income and equity securities carrying value	$ 1,830,000,000	1,930,000,000
Interest income on collateral, net of fees	0	6,000,000	$ 1,000,000
Debt Securities below Investment Grade	4,180,000,000	4,100,000,000
Fixed income and short-term investments carrying value	201,000,000
Non-income producing fixed income securities	92,000,000
Accrued investment income	539,000,000	423,000,000
Municipal
Investment [Line Items]
Fixed income securities	6,006,000,000	6,210,000,000
Municipal bonds, tax exempt value	4,850,000,000
Fixed income securities
Investment [Line Items]
Fixed income securities	32,000,000	10,000,000
Accrued investment income	$ 495,000,000	$ 389,000,000