Investments - Schedule of Bank Loans Amortized Cost by Credit Rating and Year of Origination (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Amortized cost, net	$ 765	$ 822
Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	198	246
Allowance	(11)	(22)
Amortized cost, net	187	224
NAIC 1 / A | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	10	0
NAIC 2 / BBB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	37	9
NAIC 3 / BB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	19	38
NAIC 4 / B | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	119	153
NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	13	$ 46
2019 and prior | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	25
2019 and prior | NAIC 1 / A | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2019 and prior | NAIC 2 / BBB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2019 and prior | NAIC 3 / BB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2019 and prior | NAIC 4 / B | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	25
2019 and prior | NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2020 | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	1
2020 | NAIC 1 / A | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2020 | NAIC 2 / BBB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2020 | NAIC 3 / BB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2020 | NAIC 4 / B | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	1
2020 | NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2021 | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	6
2021 | NAIC 1 / A | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2021 | NAIC 2 / BBB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2021 | NAIC 3 / BB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	2
2021 | NAIC 4 / B | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	4
2021 | NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2022 | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	2
2022 | NAIC 1 / A | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2022 | NAIC 2 / BBB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2022 | NAIC 3 / BB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2022 | NAIC 4 / B | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	2
2022 | NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2023 | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	50
2023 | NAIC 1 / A | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2023 | NAIC 2 / BBB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	0
2023 | NAIC 3 / BB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	2
2023 | NAIC 4 / B | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	38
2023 | NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	10
2024 | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	114
2024 | NAIC 1 / A | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	10
2024 | NAIC 2 / BBB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	37
2024 | NAIC 3 / BB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	15
2024 | NAIC 4 / B | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	49
2024 | NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	$ 3