Commercial Mortgage Loans By Year of Origination and Credit Quality Indicator (Detail) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	$ 6,829	$ 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	6,829	7,032
0%—50%
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	2,368	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	2,368
51%—60%
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	1,393	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	1,393
61%—75%
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	3,018	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	3,018
76%—100%
Disclosure Of Commercial Mortgage Loans By Year Of Origination And Credit Quality Indicator [Line Items]
Commercial mortgage loans, amortized cost	50	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	50
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	265	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	263	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	1,196	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	2,611	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	2,494	$ 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	271
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	19
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	23
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	229
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	172
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	65
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	20
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	930
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	75
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	84
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	771
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	17
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	38
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	223
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	396
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	256
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	905
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	86
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	220
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	599
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	3
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	9
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	104
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	422
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	367
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	480
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	115
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	86
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	275
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	4
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	18
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	19
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	67
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	205
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	171
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	692
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	127
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	154
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	388
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	23
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	31
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	36
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	159
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	261
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	205
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	3,551
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	1,946
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	826
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	756
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	23
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	196
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	147
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	471
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	1,262
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	$ 1,475