Investments - Schedule of Bank Loans Amortized Cost by Credit Rating and Year of Origination (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Amortized cost, net	$ 815	$ 822
Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	177	246
Allowance	(13)	(22)
Amortized cost, net	164	224
NAIC 2 / BBB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	4	9
NAIC 3 / BB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	20	38
NAIC 4 / B | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	134	153
NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	19	$ 46
2019 and prior | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	32
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	24
2019 and prior | NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	8
2020 | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	3
2020 | NAIC 2 / BBB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	2
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	26
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	4
2021 | NAIC 4 / B | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	17
2021 | NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	5
2022 | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	6
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	6
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	85
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	9
2023 | NAIC 4 / B | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	71
2023 | NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	5
Current | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	25
Current | NAIC 2 / BBB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	2
Current | NAIC 3 / BB | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	7
Current | NAIC 4 / B | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	15
Current | NAIC 5-6 / CCC and below | Bank loans, net
Debt Securities, Available-for-Sale [Line Items]
Amortized cost before allowance	$ 1