Lending Activities - Credit quality performance indicators for commercial mortgages (Details) $ in Millions	Dec. 31, 2022 USD ($) loan	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 50,321	$ 46,677
Allowance for credit losses	$ 38,351	$ 629	$ 814	$ 438
Commercial mortgage loans
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | loan	629	649
Total	$ 37,128	$ 35,665
Allowance for credit losses	$ 640	$ 545	$ 685	$ 336
Percent of Total	100.00%	100.00%
Percentage of total, allowance for credit losses	2.00%	2.00%
Commercial mortgage loans | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | loan	615	636
Total	$ 36,231	$ 35,015
Percent of Total	97.00%	98.00%
Commercial mortgage loans | Restructured
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | loan	10	8
Total	$ 682	$ 515
Percent of Total	2.00%	2.00%
Commercial mortgage loans | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | loan	0	0
Total	$ 0	$ 0
Percent of Total	0.00%	0.00%
Commercial mortgage loans | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | loan	4	5
Total	$ 215	$ 135
Percent of Total	1.00%	0.00%
Commercial mortgage loans | Apartments
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 14,597	$ 14,267
Allowance for credit losses	100	109
Commercial mortgage loans | Apartments | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	14,597	14,267
Commercial mortgage loans | Apartments | Restructured
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Apartments | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Apartments | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Offices
Financing Receivable, Credit Quality Indicator [Line Items]
Total	10,275	10,130
Allowance for credit losses	351	247
Commercial mortgage loans | Offices | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	9,652	9,695
Commercial mortgage loans | Offices | Restructured
Financing Receivable, Credit Quality Indicator [Line Items]
Total	450	354
Commercial mortgage loans | Offices | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Offices | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	173	81
Commercial mortgage loans | Retail
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3,816	4,857
Allowance for credit losses	81	103
Commercial mortgage loans | Retail | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3,634	4,778
Commercial mortgage loans | Retail | Restructured
Financing Receivable, Credit Quality Indicator [Line Items]
Total	140	25
Commercial mortgage loans | Retail | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Retail | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	42	54
Commercial mortgage loans | Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	6,006	3,858
Allowance for credit losses	71	47
Commercial mortgage loans | Industrial | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	6,006	3,858
Commercial mortgage loans | Industrial | Restructured
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Industrial | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Industrial | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Hotel
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,027	2,121
Allowance for credit losses	29	31
Commercial mortgage loans | Hotel | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,935	1,985
Commercial mortgage loans | Hotel | Restructured
Financing Receivable, Credit Quality Indicator [Line Items]
Total	92	136
Commercial mortgage loans | Hotel | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Hotel | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Others
Financing Receivable, Credit Quality Indicator [Line Items]
Total	407	432
Allowance for credit losses	8	8
Commercial mortgage loans | Others | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	407	432
Commercial mortgage loans | Others | Restructured
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Others | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage loans | Others | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 0	$ 0