Investments (Credit quality indicator) (Details) - Mortgage loans $ in Millions	Dec. 31, 2020 USD ($)
Debt Securities, Available-for-sale [Line Items]
2020	$ 161
2019	284
2018	103
2017	215
2016	85
Prior	246
Total	1,094
DSCR ≥1.6x | LTV less than 55%
Debt Securities, Available-for-sale [Line Items]
2020	75
2019	33
2018	36
2017	115
2016	33
Prior	156
Total	448
DSCR ≥1.6x | LTV 55% to 65%
Debt Securities, Available-for-sale [Line Items]
2020	14
2019	20
2018	14
2017	15
2016	11
Prior	0
Total	74
DSCR ≥1.6x | LTV greater than 65%
Debt Securities, Available-for-sale [Line Items]
2020	0
2019	5
2018	0
2017	0
2016	25
Prior	0
Total	30
DSCR 1.2x - 1.6x | LTV less than 55%
Debt Securities, Available-for-sale [Line Items]
2020	0
2019	17
2018	0
2017	5
2016	9
Prior	68
Total	99
DSCR 1.2x - 1.6x | LTV 55% to 65%
Debt Securities, Available-for-sale [Line Items]
2020	20
2019	29
2018	53
2017	27
2016	0
Prior	0
Total	129
DSCR 1.2x - 1.6x | LTV greater than 65%
Debt Securities, Available-for-sale [Line Items]
2020	52
2019	54
2018	0
2017	8
2016	0
Prior	12
Total	126
DSCR ≤1.2 | LTV less than 55%
Debt Securities, Available-for-sale [Line Items]
2020	0
2019	50
2018	0
2017	8
2016	7
Prior	3
Total	68
DSCR ≤1.2 | LTV 55% to 65%
Debt Securities, Available-for-sale [Line Items]
2020	0
2019	48
2018	0
2017	0
2016	0
Prior	0
Total	48
DSCR ≤1.2 | LTV greater than 65%
Debt Securities, Available-for-sale [Line Items]
2020	0
2019	28
2018	0
2017	37
2016	0
Prior	7
Total	$ 72