Investments, Amortized Cost Basis of Mortgage Loans for Each Credit Quality Indicator by Year of Origination (Details) - Commercial mortgage-backed $ in Millions	Dec. 31, 2021 USD ($)
Credit Quality Information [Abstract]
2021	$ 95
2020	160
2019	249
2018	79
2017	152
Prior	254
Total	989
DSCR Greater than or Equal to 1.6x, LTV Less than 55%
Credit Quality Information [Abstract]
2021	2
2020	75
2019	6
2018	38
2017	99
Prior	181
Total	401
DSCR Greater than or Equal to 1.6x, LTV 55% to 65%
Credit Quality Information [Abstract]
2021	5
2020	38
2019	15
2018	17
2017
Prior	24
Total	99
DSCR Greater than or Equal to 1.6x, LTV Greater than 65%
Credit Quality Information [Abstract]
2021	17
2020
2019	8
2018
2017
Prior
Total	25
DSCR Between 1.2 to 1.6x, LTV Less than 55%
Credit Quality Information [Abstract]
2021	14
2020	14
2019	95
2018
2017	5
Prior	42
Total	170
DSCR Between 1.2 to 1.6x, LTV 55% to 65%
Credit Quality Information [Abstract]
2021	36
2020
2019
2018	24
2017	10
Prior
Total	70
DSCR Between 1.2 to 1.6x, LTV Greater than 65%
Credit Quality Information [Abstract]
2021
2020	24
2019
2018
2017	8
Prior
Total	32
DSCR Less than or Equal to 1.2x, LTV Less than 55%
Credit Quality Information [Abstract]
2021
2020
2019	35
2018
2017	30
Prior
Total	65
DSCR Three, LTV 55 to 65%
Credit Quality Information [Abstract]
2021
2020
2019	28
2018
2017
Prior
Total	28
DSCR Less than or Equal to 1.2x, LTV Greater than 65%
Credit Quality Information [Abstract]
2021	21
2020	9
2019	62
2018
2017
Prior	7
Total	$ 99