Lending Activities - Credit Quality Performance Indicators for Commercial Mortgages (Details) $ in Millions	Mar. 31, 2026 USD ($) loan	Dec. 31, 2025 USD ($) loan
Financing Receivable, Credit Quality Indicator [Line Items]
Allowance for credit losses	$ 37,713	$ 37,747
Commercial mortgage and other loans
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | loan	137	145
Total	$ 2,409	$ 2,495
Allowance for credit losses	$ 77	$ 111
Percent of Total	100.00%	100.00%
Percentage of total, allowance for credit losses	3.00%	4.00%
Commercial mortgage and other loans | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | loan	133	140
Total	$ 2,351	$ 2,396
Percent of Total	98.00%	96.00%
Commercial mortgage and other loans | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | loan	0	1
Total	$ 0	$ 9
Percent of Total	0.00%	0.00%
Commercial mortgage and other loans | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Number of Loans | loan	4	4
Total	$ 58	$ 90
Percent of Total	2.00%	4.00%
Commercial mortgage and other loans | Apartments
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 750	$ 793
Allowance for credit losses	1	2
Commercial mortgage and other loans | Apartments | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	750	793
Commercial mortgage and other loans | Apartments | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage and other loans | Apartments | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage and other loans | Offices
Financing Receivable, Credit Quality Indicator [Line Items]
Total	967	986
Allowance for credit losses	56	62
Commercial mortgage and other loans | Offices | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	941	947
Commercial mortgage and other loans | Offices | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	9
Commercial mortgage and other loans | Offices | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	26	30
Commercial mortgage and other loans | Retail
Financing Receivable, Credit Quality Indicator [Line Items]
Total	325	357
Allowance for credit losses	10	37
Commercial mortgage and other loans | Retail | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	293	297
Commercial mortgage and other loans | Retail | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage and other loans | Retail | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	32	60
Commercial mortgage and other loans | Industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	153	158
Allowance for credit losses	0	0
Commercial mortgage and other loans | Industrial | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	153	158
Commercial mortgage and other loans | Industrial | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage and other loans | Industrial | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage and other loans | Hotel
Financing Receivable, Credit Quality Indicator [Line Items]
Total	164	191
Allowance for credit losses	10	10
Commercial mortgage and other loans | Hotel | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	164	191
Commercial mortgage and other loans | Hotel | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage and other loans | Hotel | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage and other loans | Others
Financing Receivable, Credit Quality Indicator [Line Items]
Total	50	10
Allowance for credit losses	0	0
Commercial mortgage and other loans | Others | In good standing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	50	10
Commercial mortgage and other loans | Others | 90 days or less delinquent
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial mortgage and other loans | Others | >90 days delinquent or in process of foreclosure
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 0	$ 0