Commercial Mortgage Loans By Year of Origination and Credit Quality Indicator (Detail) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	$ 6,876	$ 7,032
Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	6,876	7,032
0% - 50%
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	2,406	2,385
0% - 50% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	2,406
51% - 60%
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	1,342	1,342
51% - 60% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	1,342
61% - 75%
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	3,086	3,255
61% - 75% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	3,086
76% - 100%
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	42	50
76% - 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	42
Greater than 100%
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0	0
Greater than 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
Less than 1.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	246	270
1.00 - 1.25 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	264	272
1.26 - 1.50 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	1,099	1,118
1.51 - 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	3,067	3,085
Greater than 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	2,200	$ 2,287
2023 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	112
2023 | 0% - 50% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	2
2023 | 51% - 60% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	16
2023 | 61% - 75% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	94
2023 | 76% - 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2023 | Greater than 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2023 | Less than 1.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2023 | 1.00 - 1.25 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	14
2023 | 1.26 - 1.50 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	52
2023 | 1.51 - 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	44
2023 | Greater than 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	2
2022 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	939
2022 | 0% - 50% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	41
2022 | 51% - 60% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	57
2022 | 61% - 75% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	841
2022 | 76% - 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2022 | Greater than 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2022 | Less than 1.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	7
2022 | 1.00 - 1.25 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	17
2022 | 1.26 - 1.50 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	287
2022 | 1.51 - 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	575
2022 | Greater than 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	53
2021 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	917
2021 | 0% - 50% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	40
2021 | 51% - 60% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	131
2021 | 61% - 75% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	746
2021 | 76% - 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2021 | Greater than 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2021 | Less than 1.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	10
2021 | 1.00 - 1.25 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2021 | 1.26 - 1.50 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	69
2021 | 1.51 - 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	607
2021 | Greater than 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	231
2020 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	486
2020 | 0% - 50% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	98
2020 | 51% - 60% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	103
2020 | 61% - 75% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	285
2020 | 76% - 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2020 | Greater than 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2020 | Less than 1.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	6
2020 | 1.00 - 1.25 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	16
2020 | 1.26 - 1.50 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	64
2020 | 1.51 - 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	202
2020 | Greater than 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	198
2019 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	701
2019 | 0% - 50% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	118
2019 | 51% - 60% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	148
2019 | 61% - 75% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	427
2019 | 76% - 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	8
2019 | Greater than 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2019 | Less than 1.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	46
2019 | 1.00 - 1.25 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	19
2019 | 1.26 - 1.50 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	162
2019 | 1.51 - 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	266
2019 | Greater than 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	208
2018 and prior | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	3,721
2018 and prior | 0% - 50% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	2,107
2018 and prior | 51% - 60% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	887
2018 and prior | 61% - 75% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	693
2018 and prior | 76% - 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	34
2018 and prior | Greater than 100% | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	0
2018 and prior | Less than 1.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	177
2018 and prior | 1.00 - 1.25 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	198
2018 and prior | 1.26 - 1.50 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	465
2018 and prior | 1.51 - 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	1,373
2018 and prior | Greater than 2.00 | Fixed Rate Commercial Mortgage Loans
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	$ 1,508