Investments - Mortgage Loans Credit Ratings Indicator (Details) - Commercial Real Estate - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	$ 1,362	$ 1,311
1
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	10	11
2 to 4
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	1,316	1,262
5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	31	32
7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	5	6
2024
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	56
2024 | 1
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0
2024 | 2 to 4
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	56
2024 | 5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0
2024 | 7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0
2023
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	302	302
2023 | 1
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2023 | 2 to 4
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	302	302
2023 | 5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2023 | 7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2022
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	349	346
2022 | 1
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2022 | 2 to 4
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	349	346
2022 | 5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2022 | 7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2021
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	242	244
2021 | 1
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2021 | 2 to 4
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	224	225
2021 | 5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	13	13
2021 | 7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	5	6
2020
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	35	35
2020 | 1
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2020 | 2 to 4
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	35	35
2020 | 5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2020 | 7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
Prior
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	378	384
Prior | 1
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	10	11
Prior | 2 to 4
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	350	354
Prior | 5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	18	19
Prior | 7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	$ 0	$ 0