Investments - Amortized Cost Basis of Mortgage Loans for Each Credit Quality Indicator by Year of Origination (Details) - Commercial mortgage-backed $ in Millions	Jun. 30, 2023 USD ($)
Credit Quality Information [Abstract]
2023	$ 66
2022	249
2021	94
2020	149
2019	183
Prior	312
Total	1,053
DSCR Greater than or Equal to 1.6x, LTV Less than 55%
Credit Quality Information [Abstract]
2023
2022	9
2021	13
2020	111
2019	33
Prior	245
Total	411
DSCR Greater than or Equal to 1.6x, LTV 55% to 65%
Credit Quality Information [Abstract]
2023
2022
2021
2020
2019	8
Prior
Total	8
DSCR Greater than or Equal to 1.6x, LTV Greater than 65%
Credit Quality Information [Abstract]
2023
2022	31
2021	11
2020
2019
Prior
Total	42
DSCR Between 1.2 to 1.6x, LTV Less than 55%
Credit Quality Information [Abstract]
2023	28
2022	5
2021	49
2020	14
2019	42
Prior	51
Total	189
DSCR Between 1.2 to 1.6x, LTV 55% to 65%
Credit Quality Information [Abstract]
2023	12
2022	43
2021
2020	24
2019
Prior	9
Total	88
DSCR Between 1.2 to 1.6x, LTV Greater than 65%
Credit Quality Information [Abstract]
2023
2022	58
2021
2020
2019
Prior
Total	58
DSCR Less than or Equal to 1.2x, LTV Less than 55%
Credit Quality Information [Abstract]
2023
2022	35
2021
2020
2019	34
Prior
Total	69
DSCR Three, LTV 55 to 65%
Credit Quality Information [Abstract]
2023	13
2022	41
2021
2020
2019	43
Prior
Total	97
DSCR Less than or Equal to 1.2x, LTV Greater than 65%
Credit Quality Information [Abstract]
2023	13
2022	27
2021	21
2020
2019	23
Prior	7
Total	$ 91