Investments - Mortgage Loans Credit Ratings Indicator (Details) - Commercial Real Estate - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	$ 1,273	$ 1,044
1
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	12	15
2 to 4
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	1,235	1,022
5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	26	7
7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2023
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	259
2023 | 1
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0
2023 | 2 to 4
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	259
2023 | 5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0
2023 | 7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0
2022
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	344	326
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	344	326
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	245	247
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	239	247
2021 | 5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	6	0
2021 | 7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2020
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	35	36
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	36
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
2019
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	11	11
2019 | 1
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2019 | 2 to 4
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	11	11
2019 | 5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
2019 | 7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	0	0
Prior
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	379	424
Prior | 1
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	12	15
Prior | 2 to 4
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	347	402
Prior | 5 and 6
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	20	7
Prior | 7
Mortgage Loans on Real Estate [Line Items]
Mortgage loans	$ 0	$ 0