v3.26.1
Fair Value Hierarchy - Schedule of Level 3 Assets, and Ranges and Weighted Averages of Significant Unobservable Inputs (Detail)
$ in Millions
Jun. 30, 2026
USD ($)
yr
Mar. 31, 2026
USD ($)
Dec. 31, 2025
USD ($)
yr
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Total financial assets at fair value | $ $ 1,157,158 $ 1,139,251 $ 963,966
Level 3      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Total financial assets at fair value | $ 20,839 $ 20,836 20,324
Level 3 | Loans and securities backed by real estate      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Total financial assets at fair value | $ $ 103   $ 155
Level 3 | Loans and securities backed by real estate | Minimum | Yield      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.035   0.031
Level 3 | Loans and securities backed by real estate | Minimum | Recovery rate      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.180   0.223
Level 3 | Loans and securities backed by real estate | Minimum | Duration (years)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.2   0.3
Level 3 | Loans and securities backed by real estate | Maximum | Yield      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.446   0.451
Level 3 | Loans and securities backed by real estate | Maximum | Recovery rate      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.625   0.625
Level 3 | Loans and securities backed by real estate | Maximum | Duration (years)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 6.9   9.0
Level 3 | Loans and securities backed by real estate | Weighted Average | Yield      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.124   0.106
Level 3 | Loans and securities backed by real estate | Weighted Average | Recovery rate      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.365   0.365
Level 3 | Loans and securities backed by real estate | Weighted Average | Duration (years)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 3.4   3.4
Level 3 | Corporate debt instruments      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Total financial assets at fair value | $ $ 724   $ 484
Level 3 | Corporate debt instruments | Minimum | Yield      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.025   0.021
Level 3 | Corporate debt instruments | Minimum | Recovery rate      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.041   0.041
Level 3 | Corporate debt instruments | Minimum | Duration (years)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 1.6   2.3
Level 3 | Corporate debt instruments | Maximum | Yield      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.213   0.180
Level 3 | Corporate debt instruments | Maximum | Recovery rate      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.691   0.720
Level 3 | Corporate debt instruments | Maximum | Duration (years)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 4.7   14.7
Level 3 | Corporate debt instruments | Weighted Average | Yield      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.091   0.080
Level 3 | Corporate debt instruments | Weighted Average | Recovery rate      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.376   0.323
Level 3 | Corporate debt instruments | Weighted Average | Duration (years)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 2.9   3.9
Level 3 | Other      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Total financial assets at fair value | $ $ 306   $ 265
Level 3 | Other | Minimum | Yield      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.078   0.084
Level 3 | Other | Minimum | Duration (years)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.4   0.2
Level 3 | Other | Maximum | Yield      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.256   0.300
Level 3 | Other | Maximum | Duration (years)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 6.5   8.7
Level 3 | Other | Weighted Average | Yield      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 0.168   0.175
Level 3 | Other | Weighted Average | Duration (years)      
Fair Value Measurement Inputs and Valuation Techniques [Line Items]      
Measurement input 3.0   2.6