Investments - Schedule of Residential Loans Segregated by Risk Rating Exposure and Non-accrual Loans by Amortized Cost (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Amortized Cost of Non-Accrual Loans [Abstract]
Amortized cost of loans on non-accrual	$ 76	$ 71
Residential mortgages
Credit Quality Indicator Current Year [Abstract]
2023	237	771
2022	955	900
2021	886	229
2020	212	223
2019	212	24
Prior	202	33
Credit Quality Indicator Prior Year [Abstract]
2022	237	771
2021	955	900
2020	886	229
2019	212	223
2018	212	24
Prior	202	33
Total	2,704	2,180
Amortized Cost of Non-Accrual Loans [Abstract]
Amortized cost of loans on non-accrual	67	62
Commercial mortgages
Credit Quality Indicator Current Year [Abstract]
2023		350
2022		1,300
2021		488
2020		0
2019		0
Prior		278
Loans	2,513	2,407
Credit Quality Indicator Prior Year [Abstract]
2022		350
2021		1,300
2020		488
2019		0
2018		0
Prior		278
Total	2,534	2,416
Amortized Cost of Non-Accrual Loans [Abstract]
Amortized cost of loans on non-accrual	9	9
Current (less than 30 days past due) | Residential mortgages
Credit Quality Indicator Current Year [Abstract]
2023	236	766
2022	948	884
2021	846	214
2020	190	185
2019	183	23
Prior	194	33
Credit Quality Indicator Prior Year [Abstract]
2022	236	766
2021	948	884
2020	846	214
2019	190	185
2018	183	23
Prior	194	33
Total	2,597	2,105
Current (less than 30 days past due) | Commercial mortgages
Credit Quality Indicator Current Year [Abstract]
2023		350
2022		1,300
2021		488
2020		0
2019		0
Prior		269
Loans	2,504
Credit Quality Indicator Prior Year [Abstract]
2022		350
2021		1,300
2020		488
2019		0
2018		0
Prior		269
Total		2,407
30-89 days past due | Residential mortgages
Credit Quality Indicator Current Year [Abstract]
2023	1	2
2022	3	7
2021	15	0
2020	9	4
2019	6	0
Prior	6	0
Credit Quality Indicator Prior Year [Abstract]
2022	1	2
2021	3	7
2020	15	0
2019	9	4
2018	6	0
Prior	6	0
Total	40	13
30-89 days past due | Commercial mortgages
Credit Quality Indicator Current Year [Abstract]
2023		0
2022		0
2021		0
2020		0
2019		0
Prior		0
Loans	0
Credit Quality Indicator Prior Year [Abstract]
2022		0
2021		0
2020		0
2019		0
2018		0
Prior		0
Total		0
90 days or more past due | Residential mortgages
Credit Quality Indicator Current Year [Abstract]
2023	0	3
2022	4	9
2021	25	15
2020	13	34
2019	23	1
Prior	2	0
Credit Quality Indicator Prior Year [Abstract]
2022	0	3
2021	4	9
2020	25	15
2019	13	34
2018	23	1
Prior	2	0
Total	67	62
90 days or more past due | Commercial mortgages
Credit Quality Indicator Current Year [Abstract]
2023		0
2022		0
2021		0
2020		0
2019		0
Prior		9
Loans	$ 9
Credit Quality Indicator Prior Year [Abstract]
2022		0
2021		0
2020		0
2019		0
2018		0
Prior		9
Total		$ 9