Investments (Credit quality indicator) (Details) - Mortgage loans $ in Millions	Sep. 30, 2023 USD ($)
Debt Securities, Available-for-sale [Line Items]
2023	$ 75
2022	248
2021	81
2020	135
2019	182
Prior	309
Total	1,030
DSCR ≥1.6x | LTV less than 55%
Debt Securities, Available-for-sale [Line Items]
2023	0
2022	9
2021	8
2020	97
2019	61
Prior	242
Total	417
DSCR ≥1.6x | LTV 55% to 65%
Debt Securities, Available-for-sale [Line Items]
2023	0
2022	0
2021	5
2020	0
2019	8
Prior	0
Total	13
DSCR ≥1.6x | LTV greater than 65%
Debt Securities, Available-for-sale [Line Items]
2023	0
2022	31
2021	11
2020	0
2019	0
Prior	0
Total	42
DSCR 1.2x - 1.6x | LTV less than 55%
Debt Securities, Available-for-sale [Line Items]
2023	28
2022	5
2021	0
2020	14
2019	29
Prior	28
Total	104
DSCR 1.2x - 1.6x | LTV 55% to 65%
Debt Securities, Available-for-sale [Line Items]
2023	15
2022	36
2021	36
2020	24
2019	0
Prior	32
Total	143
DSCR 1.2x - 1.6x | LTV greater than 65%
Debt Securities, Available-for-sale [Line Items]
2023	0
2022	65
2021	0
2020	0
2019	0
Prior	0
Total	65
DSCR ≤1.2 | LTV less than 55%
Debt Securities, Available-for-sale [Line Items]
2023	22
2022	34
2021	0
2020	0
2019	0
Prior	0
Total	56
DSCR ≤1.2 | LTV 55% to 65%
Debt Securities, Available-for-sale [Line Items]
2023	10
2022	41
2021	0
2020	0
2019	43
Prior	0
Total	94
DSCR ≤1.2 | LTV greater than 65%
Debt Securities, Available-for-sale [Line Items]
2023	0
2022	27
2021	21
2020	0
2019	41
Prior	7
Total	$ 96